Space debris

"Space Junk" redirects here. For other uses, see Space Junk (disambiguation).

"Cosmic debris" redirects here. For the Frank Zappa song, see Cosmik Debris.

Space debris (also known as space junk, space pollution,^[1] space waste, space trash, space garbage, or cosmic debris^[2]) are defunct human-made objects in space—principally in Earth orbit—which no longer serve a useful function. These include derelict spacecraft—nonfunctional spacecraft and abandoned launch vehicle stages—mission-related debris, and particularly numerous in Earth orbit, fragmentation debris from the breakup of derelict rocket bodies and spacecraft. In addition to derelict human-made objects left in orbit, other examples of space debris include fragments from their disintegration, erosion and collisions or even paint flecks, solidified liquids expelled from spacecraft, and unburned particles from solid rocket motors. Space debris represents a risk to spacecraft.^[3]

A computer-generated image representing the locations, but not relative sizes, of space debris as could be seen from high Earth orbit. The two main debris fields are the ring of objects in geosynchronous Earth orbit (GEO) and the cloud of objects in low Earth orbit (LEO).

Space debris is typically a negative externality—it creates an external cost on others from the initial action to launch or use a spacecraft in near-Earth orbit—a cost that is typically not taken into account nor fully accounted for in the cost^[4][5] by the launcher or payload owner.^[6][1][7]

Several spacecraft, both crewed and uncrewed, have been damaged or destroyed by space debris. The measurement, mitigation, and potential removal of debris are conducted by some participants in the space industry.^[8]

As of November 2022^[update], the US Space Surveillance Network reported 25,857 artificial objects in orbit above the Earth,^[9] including 5,465 operational satellites.^[10] However, these are just the objects large enough to be tracked and in an orbit that makes tracking possible. Satellite debris that is in a Molnya orbit, such as the Kosmos Ono series, might be too high above the northern hemisphere to be tracked.^[11] As of January 2019^[update], more than 128 million pieces of debris smaller than 1 cm (0.4 in), about 900,000 pieces of debris 1–10 cm, and around 34,000 of pieces larger than 10 cm (3.9 in) were estimated to be in orbit around the Earth.^[8] When the smallest objects of artificial space debris (paint flecks, solid rocket exhaust particles, etc.) are grouped with micrometeoroids, they are together sometimes referred to by space agencies as MMOD (Micrometeoroid and Orbital Debris). Collisions with debris have become a hazard to spacecraft; the smallest objects cause damage akin to sandblasting, especially to solar panels and optics like telescopes or star trackers that cannot easily be protected by a ballistic shield.^[12]

Below 2,000 km (1,200 mi) Earth-altitude, pieces of debris are denser than meteoroids; most are dust from solid rocket motors, surface erosion debris like paint flakes, and frozen coolant from Soviet nuclear-powered satellites.^[13][14][15] For comparison, the International Space Station orbits in the 300–400 kilometres (190–250 mi) range, while the two most recent large debris events—the 2007 Chinese antisat weapon test and the 2009 satellite collision—occurred at 800 to 900 kilometres (500 to 560 mi) altitude.^[16] The ISS has Whipple shielding to resist damage from small MMOD; however, known debris with a collision chance over 1/10,000 are avoided by maneuvering the station.

History

Space debris began to accumulate in Earth orbit immediately with the first launch of an artificial satellite Sputnik 1 into orbit in October 1957. But even before that humans might have produced ejecta that became space debris, as in the August 1957 Pascal B test.^[17][18] Going back even earlier, there was natural ejecta from Earth in orbit.

After the launch of Sputnik, the North American Aerospace Defense Command (NORAD) began compiling a database (the Space Object Catalog) of all known rocket launches and objects reaching orbit: satellites, protective shields and upper-stages of launch vehicles. NASA later published modified versions of the database in two-line element set,^[19] and beginning in the early 1980s the CelesTrak bulletin board system re-published them.^[20]

 

Gabbard diagram of almost 300 pieces of debris from the disintegration of the five-month-old third stage of the Chinese Long March 4 booster on 11 March 2000

The trackers (NORAD) who fed the database were aware of other objects in orbit, many of which were the result of in-orbit explosions.^[21] Some were deliberately caused during the 1960s anti-satellite weapon (ASAT) testing, and others were the result of rocket stages blowing up in orbit as leftover propellant expanded and ruptured their tanks. To improve tracking, NORAD employee John Gabbard kept a more detailed database of as many objects as he could identify.^[22]

Studying the explosions, In March 1971, Gabbard developed a technique for predicting the orbital paths of their products, and Gabbard diagrams (or plots) are now widely used. These studies were used to improve the modeling of orbital evolution and decay.^[23]

When the NORAD database became publicly available during the 1970s,^{[clarification needed]} techniques developed for the asteroid-belt were applied to the study^{[by whom?]} to the database of known artificial satellite Earth objects.^{[citation needed]}

 

Baker-Nunn cameras were widely used to study space debris.

In addition to approaches to debris reduction where time and natural gravitational/atmospheric effects help to clear space debris, or a variety of technological approaches that have been proposed (with most not implemented) to reduce space debris, a number of scholars have observed that institutional factors—political, legal, economic and cultural "rules of the game"—are the greatest impediment to the cleanup of near-Earth space. By 2014, there was little commercial incentive to reduce space debris, since the cost of dealing with it is not assigned to the entity producing it, but rather falls on all users of the space environment, and rely on human society as a whole that benefits from space technologies and knowledge. A number of suggestions for improving institutions so as to increase the incentives to reduce space debris have been made. These include government mandates to create incentives, as well as companies coming to see economic benefit to reducing debris more aggressively than existing government standard practices.^[24] In 1979 NASA founded the Orbital Debris Program to research mitigation measures for space debris in Earth orbit.^[25][26]

Debris growth

During the 1980s, NASA and other U.S. groups attempted to limit the growth of debris. One trial solution was implemented by McDonnell Douglas in 1981 for the Delta launch vehicle, by having the booster move away from its payload and vent any propellant remaining in its tanks.^[27] This eliminated one source for pressure buildup in the tanks which had previously caused them to explode and create additional orbital debris.^[28] Other countries were slower to adopt this measure and, due especially to a number of launches by the Soviet Union, the problem grew throughout the decade.^[29]

A new battery of studies followed as NASA, NORAD and others attempted to better understand the orbital environment, with each adjusting the number of pieces of debris in the critical-mass zone upward. Although in 1981 (when Schefter's article was published) the number of objects was estimated at 5,000,^[21] new detectors in the Ground-based Electro-Optical Deep Space Surveillance system found new objects. By the late 1990s, it was thought that most of the 28,000 launched objects had already decayed and about 8,500 remained in orbit.^[30] By 2005 this was adjusted upward to 13,000 objects,^[31] and a 2006 study increased the number to 19,000 as a result of an ASAT and a satellite collision.^[32] In 2011, NASA said that 22,000 objects were being tracked.^[33]

A 2006 NASA model suggested that if no new launches took place the environment would retain the then-known population until about 2055, when it would increase on its own.^[34][35] Richard Crowther of Britain's Defence Evaluation and Research Agency said in 2002 that he believed the cascade would begin about 2015.^[36] The National Academy of Sciences, summarizing the professional view, noted widespread agreement that two bands of LEO space—900 to 1,000 km (620 mi) and 1,500 km (930 mi)—were already past critical density.^[37]

In the 2009 European Air and Space Conference, University of Southampton researcher Hugh Lewis predicted that the threat from space debris would rise 50 percent in the next decade and quadruple in the next 50 years. As of 2009^[update], more than 13,000 close calls were tracked weekly.^[38]

A 2011 report by the U.S. National Research Council warned NASA that the amount of orbiting space debris was at a critical level. According to some computer models, the amount of space debris "has reached a tipping point, with enough currently in orbit to continually collide and create even more debris, raising the risk of spacecraft failures". The report called for international regulations limiting debris and research of disposal methods.^[39]

 

Objects in Earth orbit including fragmentation debris. November 2020 NASA:ODPO

Debris history in particular years

• By mid-1994 there had been 68 breakups or debris "anomalous events" involving satellites launched by the former Soviet Union/Russia and 18 similar events had been discovered involving rocket bodies and other propulsion-related operational debris.^[40]
• As of 2009^[update], 19,000 debris over 5 cm (2 in) were tracked by United States Space Surveillance Network.^[16]
• As of July 2013^[update], estimates of more than 170 million debris smaller than 1 cm (0.4 in), about 670,000 debris 1–10 cm, and approximately 29,000 larger pieces of debris are in orbit.^[41]
• As of July 2016^[update], nearly 18,000 artificial objects are orbiting above Earth,^[42] including 1,419 operational satellites.^[43]
• As of October 2019^[update], nearly 20,000 artificial objects in orbit above the Earth,^[9] including 2,218 operational satellites.^[10]

Characterization

Size

There are estimated to be over 128 million pieces of debris smaller than 1 cm (0.39 in) as of January 2019. There are approximately 900,000 pieces from 1 to 10 cm. The current count of large debris (defined as 10 cm across or larger^[44]) is 34,000.^[8] The technical measurement cutoff^{[clarification needed]} is c. 3 mm (0.12 in).^[45] As of 2020, there are 8,000 metric tons of debris in orbit, a figure that is expected to increase.^[46]

Low Earth orbit

 

Satellite hit by a space debris, animation by ESA

In the orbits nearest to Earth—less than 2,000 km (1,200 mi) orbital altitude, referred to as low-Earth orbit (LEO)—there have traditionally been few "universal orbits" that keep a number of spacecraft in particular rings (in contrast to GEO, a single orbit that is widely used by over 500 satellites). This is beginning to change in 2019, and several companies have begun to deploy the early phases of satellite internet constellations, which will have many universal orbits in LEO with 30 to 50 satellites per orbital plane and altitude. Traditionally, the most populated LEO orbits have been a number of sun-synchronous satellites that keep a constant angle between the Sun and the orbital plane, making Earth observation easier with consistent sun angle and lighting. Sun-synchronous orbits are polar, meaning they cross over the polar regions. LEO satellites orbit in many planes, typically up to 15 times a day, causing frequent approaches between objects. The density of satellites—both active and derelict—is much higher in LEO.^[47]

Orbits are affected by gravitational perturbations (which in LEO include unevenness of the Earth's gravitational field due to variations in the density of the planet), and collisions can occur from any direction. The average impact speed of collisions in Low Earth Orbit is 10 km/s with maximums reaching above 14 km/s due to orbital eccentricity.^[48] The 2009 satellite collision occurred at a closing speed of 11.7 km/s (26,000 mph),^[49] creating over 2,000 large debris fragments.^[50] These debris cross many other orbits and increase debris collision risk.

It is theorized that a sufficiently large collision of spacecraft could potentially lead to a cascade effect, or even make some particular low Earth orbits effectively unusable for long term use by orbiting satellites, a phenomenon known as the Kessler syndrome.^[51] The theoretical effect is projected to be a theoretical runaway chain reaction of collisions that could occur, exponentially increasing the number and density of space debris in low-Earth orbit, and has been hypothesized to ensue beyond some critical density.^[52]

Crewed space missions are mostly at 400 km (250 mi) altitude and below, where air drag helps clear zones of fragments. The upper atmosphere is not a fixed density at any particular orbital altitude; it varies as a result of atmospheric tides and expands or contracts over longer time periods as a result of space weather.^[53] These longer-term effects can increase drag at lower altitudes; the 1990s expansion was a factor in reduced debris density.^[54] Another factor was fewer launches by Russia; the Soviet Union made most of their launches in the 1970s and 1980s.^[55]: 7

Higher altitudes

At higher altitudes, where air drag is less significant, orbital decay takes longer. Slight atmospheric drag, lunar perturbations, Earth's gravity perturbations, solar wind and solar radiation pressure can gradually bring debris down to lower altitudes (where it decays), but at very high altitudes this may take centuries.^[56] Although high-altitude orbits are less commonly used than LEO and the onset of the problem is slower, the numbers progress toward the critical threshold more quickly.^{[contradictory][page needed][57]}

Many communications satellites are in geostationary orbits (GEO), clustering over specific targets and sharing the same orbital path. Although velocities are low between GEO objects, when a satellite becomes derelict (such as Telstar 401) it assumes a geosynchronous orbit; its orbital inclination increases about .8° and its speed increases about 160 km/h (99 mph) per year. Impact velocity peaks at about 1.5 km/s (0.93 mi/s). Orbital perturbations cause longitude drift of the inoperable spacecraft and precession of the orbital plane. Close approaches (within 50 meters) are estimated at one per year.^[58] The collision debris pose less short-term risk than from an LEO collision, but the satellite would likely become inoperable. Large objects, such as solar-power satellites, are especially vulnerable to collisions.^[59]

Although the ITU now requires proof a satellite can be moved out of its orbital slot at the end of its lifespan, studies suggest this is insufficient.^[60] Since GEO orbit is too distant to accurately measure objects under 1 m (3 ft 3 in), the nature of the problem is not well known.^[61] Satellites could be moved to empty spots in GEO, requiring less maneuvering and making it easier to predict future motion.^[62] Satellites or boosters in other orbits, especially stranded in geostationary transfer orbit, are an additional concern due to their typically high crossing velocity.

Despite efforts to reduce risk, spacecraft collisions have occurred. The European Space Agency telecom satellite Olympus-1 was struck by a meteoroid on 11 August 1993 and eventually moved to a graveyard orbit.^[63] On 29 March 2006, the Russian Express-AM11 communications satellite was struck by an unknown object and rendered inoperable;^[64] its engineers had enough contact time with the satellite to send it into a graveyard orbit.

Sources

Dead spacecraft

Main category: Derelict satellites orbiting Earth

Main category: Spacecraft that broke apart in space

 

Vanguard 1 is expected to remain in orbit for 240 years.^[65][66]

In 1958, the United States launched Vanguard I into a medium Earth orbit (MEO). As of October 2009^[update], it, the upper stage of its launch rocket and associated piece of debris, are the oldest surviving artificial space objects still in orbit and are expected to be until after the year 2250.^[67][68] As of May 2022^[update], the Union of Concerned Scientists listed 5,465 operational satellites from a known population of 27,000 pieces of orbital debris tracked by NORAD.^[69][70]

While sometimes satellites are simply left in orbit when they're no longer useful, many countries require that satellites go through passivation at the end of their life. They are then either boosted into a higher, "graveyard" orbit or a lower, short-term orbit. But even satellites that have been properly moved to a higher orbit have an eight-percent probability of puncture and coolant release over a 50-year period. The coolant freezes into droplets of solid sodium-potassium alloy, creating more debris.^[13][71]

Despite the use of passivization, or prior to its standardization, many satellites and rocket bodies have exploded or broken apart on orbit. In February 2015, for example, the USAF Defense Meteorological Satellite Program Flight 13 (DMSP-F13) exploded on orbit, creating at least 149 debris objects, which were expected to remain in orbit for decades.^[72] Later that same year, NOAA-16 which had been decommissioned after an anomaly in June 2014, broke apart on orbit into at least 275 pieces.^[73] For older programs, such as the Soviet-era Meteor 2 and Kosmos satellites, design flaws resulted in numerous break-ups - at least 68 by 1994 - following decommissioning, resulting in more debris.^[40]

In addition to the accidental creation of debris, some has been made intentionally through the deliberate destruction of satellites. This has been done as a test of anti-satellite or anti-ballistic missile technology, or to prevent a sensitive satellite from being examined by a foreign power.^[40] The United States has conducted over 30 anti-satellite weapons tests (ASATs), the Soviet Union/Russia has performed at least 27, China has performed 10 and India has performed at least one.^[74][75] The most recent ASATs were the Chinese interception of FY-1C, Russian trials of its PL-19 Nudol, the American interception of USA-193 and India's interception of an unstated live satellite.^[75]

Lost equipment

 

A drifting thermal blanket photographed in 1998 during STS-88.

Space debris includes a glove lost by astronaut Ed White on the first American space-walk (EVA), a camera lost by Michael Collins near Gemini 10, a thermal blanket lost during STS-88, garbage bags jettisoned by Soviet cosmonauts during Mir's 15-year life,^[76] a wrench, and a toothbrush.^[77] Sunita Williams of STS-116 lost a camera during an EVA. During an STS-120 EVA to reinforce a torn solar panel, a pair of pliers was lost, and in an STS-126 EVA, Heidemarie Stefanyshyn-Piper lost a briefcase-sized tool bag.^[78]

Boosters

Main category: Spacecraft that broke apart in space

 

Spent upper stage of a Delta II rocket, photographed by the XSS 10 satellite

Rocket upper stages which end up in orbit are a significant source of space debris. In characterizing the problem of space debris, it was learned that much debris was due to rocket upper stages (e.g. the Inertial Upper Stage) which end up in orbit, and break up due to decomposition of unvented unburned fuel.^[79] The first such instance involved the launch of the Transit-4a satellite in 1961. Two hours after insertion the Ablestar upper stage exploded. But even boosters that don't break apart can be a problem as a major known impact event involved an (intact) Ariane booster.^[55]: 2

Although NASA and the United States Air Force now require upper-stage passivation, other launchers - such as the Chinese and Russian space agencies - do not. Lower stages, like the Space Shuttle's solid rocket boosters or Apollo program's Saturn IB launch vehicles, do not reach orbit.^[80]

 

Orbit of 2020 SO

Examples:

• Two Japanese H-2A rockets rockets broke up in 2006.^[81]
• A Russian Briz-M booster stage exploded in orbit over South Australia on 19 February 2007. Launched on 28 February 2006 carrying an Arabsat-4A communications satellite, it malfunctioned before it could use up its propellant. Although the explosion was captured on film by astronomers, due to the orbit path the debris cloud has been difficult to measure with radar. By 21 February 2007, over 1,000 fragments were identified.^[82][83] A 14 February 2007 breakup was recorded by Celestrak.^[84]
• Another Briz-M broke up on 16 October 2012 after a failed 6 August Proton-M launch. The amount and size of the debris was unknown.^[85]
• The second stage of the Zenit-2, called the SL-16 by western governments, along with the second stages of the Vostok and Kosmos launch vehicles, make up about 20% of the total mass of launch debris in Low Earth Orbit (LEO).^[86] An analysis that determined the 50 “statistically most concerning” debris objects in low Earth orbit determined that the top 20 were all Zenit-2 upper stages.^[87]
• a Delta II rocket used to launch NASA’s 1989 COBE spacecraft exploded on December 3, 2006. This occurred even though its residual fuel had already been vented to space.^[81]
• In 2018–2019, three different Atlas V Centaur second stages broke up.^[88][89][90]
• In December 2020, scientists confirmed that a previously detected near-Earth object, 2020 SO, was rocket booster space junk launched in 1966 orbiting Earth and the Sun.^[91]
• At least eight Delta rockets have contributed orbital debris in the sun-synchronous low earth orbit environment. The variant of the Delta upper stage that was used in the 1970's was found to be prone to in-orbit explosions. Starting in 1981, depletion burns - to get rid of excess propellant - became standard and no Delta Rocket Bodies launched after 1981 experience severe fragmentations afterward, but some of those launched prior to 1981 continued to explode. In 1991, the Delta 1975-052B fragmented, 16 years after launch, demonstrating the resilience of the propellent.^[92]

Weapons

Main category: Intentionally destroyed artificial satellites

A past debris source was the testing of anti-satellite weapons (ASATs) by the U.S. and Soviet Union during the 1960s and 1970s. North American Aerospace Defense Command (NORAD) files only contained data for Soviet tests, and debris from U.S. tests were only identified later.^[93] By the time the debris problem was understood, widespread ASAT testing had ended; the U.S. Program 437 was shut down in 1975.^[94]

The U.S. restarted their ASAT programs in the 1980s with the Vought ASM-135 ASAT. A 1985 test destroyed a 1-tonne (2,200 lb) satellite orbiting at 525 km (326 mi), creating thousands of debris larger than 1 cm (0.39 in). Due to the altitude, atmospheric drag decayed the orbit of most debris within a decade. A de facto moratorium followed the test.^[95]

 

Known orbit planes of Fengyun-1C debris one month after the weather satellite's disintegration by the Chinese ASAT

China's government was condemned for the military implications and the amount of debris from the 2007 anti-satellite missile test,^[96] the largest single space debris incident in history (creating over 2,300 pieces golf-ball size or larger, over 35,000 1 cm (0.4 in) or larger, and one million pieces 1 mm (0.04 in) or larger). The target satellite orbited between 850 km (530 mi) and 882 km (548 mi), the portion of near-Earth space most densely populated with satellites.^[97] Since atmospheric drag is low at that altitude, the debris is slow to return to Earth, and in June 2007 NASA's Terra environmental spacecraft maneuvered to avoid impact from the debris.^[98] Dr. Brian Weeden, U.S. Air Force officer and Secure World Foundation staff member, noted that the 2007 Chinese satellite explosion created an orbital debris of more than 3,000 separate objects that then required tracking.^[99] On 20 February 2008, the U.S. launched an SM-3 missile from the USS Lake Erie to destroy a defective U.S. spy satellite thought to be carrying 450 kg (1,000 lb) of toxic hydrazine propellant. The event occurred at about 250 km (155 mi), and the resulting debris has a perigee of 250 km (155 mi) or lower.^[100] The missile was aimed to minimize the amount of debris, which (according to Pentagon Strategic Command chief Kevin Chilton) had decayed by early 2009.^[101]

On 27 March 2019, Indian Prime Minister Narendra Modi announced that India shot down one of its own LEO satellites with a ground-based missile. He stated that the operation, part of Mission Shakti, would defend the country's interests in space. Afterwards, US Air Force Space Command announced they were tracking 270 new pieces of debris but expected the number to grow as data collection continues.^[102]

On 15 November 2021, the Russian Defense Ministry destroyed Kosmos 1408^[103] orbiting at around 450 km, creating "more than 1,500 pieces of trackable debris and hundreds of thousands of pieces of un-trackable debris" according to the US State Department.^[104]

The vulnerability of satellites to debris and the possibility of attacking LEO satellites to create debris clouds has triggered speculation that it is possible for countries unable to make a precision attack.^{[clarification needed]} An attack on a satellite of 10 t (22,000 lb) or more would heavily damage the LEO environment.^[95]

Hazards

 

A micrometeoroid left this crater on the surface of Space Shuttle Challenger's front window on STS-7.

To spacecraft

Space junk can be a hazard to active satellites and spacecraft. It has been theorized that Earth orbit could even become impassable if the risk of collision grows too high.^{[105][failed verification]}

However, since the risk to spacecraft increases with exposure to high debris densities, it is more accurate to say that LEO would be rendered unusable by orbiting craft. The threat to craft passing through LEO to reach a higher orbit would be much lower owing to the very short time span of the crossing.

Uncrewed spacecraft

Although spacecraft are typically protected by Whipple shields, solar panels, which are exposed to the Sun, wear from low-mass impacts. Even small impacts can produce a cloud of plasma which is an electrical risk to the panels.^[106]

Satellites are believed to have been destroyed by micrometeorites and (small) orbital debris (MMOD). The earliest suspected loss was of Kosmos 1275, which disappeared on 24 July 1981 (a month after launch). Kosmos contained no volatile fuel, therefore, there appeared to be nothing internal to the satellite which could have caused the destructive explosion which took place. However, the case has not been proven and another hypothesis forwarded is that the battery exploded. Tracking showed it broke up, into 300 new objects.^[107]

Many impacts have been confirmed since. For example, on 24 July 1996, the French microsatellite Cerise was hit by fragments of an Ariane-1 H-10 upper-stage booster which exploded in November 1986.^[55]: 2 On 29 March 2006, the Russian Ekspress AM11 communications satellite was struck by an unknown object and rendered inoperable.^[64] On 13 October 2009, Terra suffered a single battery cell failure anomaly and a battery heater control anomaly which were subsequently considered likely the result of an MMOD strike.^[108] On 12 March 2010, Aura lost power from one-half of one of its 11 solar panels and this was also attributed to an MMOD strike.^[109] On 22 May 2013, GOES 13 was hit by an MMOD which caused it to lose track of the stars that it used to maintain an operational attitude. It took nearly a month for the spacecraft to return to operation.^[110]

The first major satellite collision occurred on 10 February 2009. The 950 kg (2,090 lb) derelict satellite Kosmos 2251 and the operational 560 kg (1,230 lb) Iridium 33 collided, 500 mi (800 km)^[111] over northern Siberia. The relative speed of impact was about 11.7 km/s (7.3 mi/s), or about 42,120 km/h (26,170 mph).^[112] Both satellites were destroyed, creating thousands of pieces of new smaller debris, with legal and political liability issues unresolved even years later.^{[113][114][115]} On 22 January 2013, BLITS (a Russian laser-ranging satellite) was struck by debris suspected to be from the 2007 Chinese anti-satellite missile test, changing both its orbit and rotation rate.^[116]

Satellites sometimes^{[clarification needed]} perform Collision Avoidance Maneuvers and satellite operators may monitor space debris as part of maneuver planning. For example, in January 2017, the European Space Agency made the decision to alter orbit of one of its three^[117] Swarm mission spacecraft, based on data from the US Joint Space Operations Center, to lower the risk of collision from Cosmos-375, a derelict Russian satellite.^[118]

Crewed spacecraft

Crewed flights are naturally particularly sensitive to the hazards that could be presented by space debris conjunctions in the orbital path of the spacecraft. Examples of occasional avoidance maneuvers, or longer-term space debris wear, have occurred in Space Shuttle missions, the MIR space station, and the International Space Station.

Space Shuttle missions

 

Space Shuttle Discovery's lower starboard wing and Thermal Protection System tiles, photographed on STS-114 during an R-Bar Pitch Manoeuvre where astronauts examine the TPS for any damage during ascent

From the early Space Shuttle missions, NASA used NORAD space monitoring capabilities to assess the Shuttle's orbital path for debris. In the 1980s, this used a large proportion of NORAD capacity.^[28] The first collision-avoidance maneuver occurred during STS-48 in September 1991,^[119] a seven-second thruster burn to avoid debris from the derelict satellite Kosmos 955.^[120] Similar maneuvers were initiated on missions 53, 72 and 82.^[119]

One of the earliest events to publicize the debris problem occurred on Space Shuttle Challenger's second flight, STS-7. A fleck of paint struck its front window, creating a pit over 1 mm (0.04 in) wide. On STS-59 in 1994, Endeavour's front window was pitted about half its depth. Minor debris impacts increased from 1998.^[121]

Window chipping and minor damage to thermal protection system tiles (TPS) were already common by the 1990s. The Shuttle was later flown tail-first to take a greater proportion of the debris load on the engines and rear cargo bay, which are not used in orbit or during descent, and thus are less critical for post-launch operation. When flying attached to the ISS, the two connected spacecraft were flipped around so the better-armoured station shielded the orbiter.^[122]

 

Space Shuttle Endeavour had a major impact on its radiator during STS-118. The entry hole is about 5.5 mm (0.22 in), and the exit hole is twice as large.

A NASA 2005 study concluded that debris accounted for approximately half of the overall risk to the Shuttle.^[122][123] Executive-level decision to proceed was required if the catastrophic impact was likelier than 1 in 200. On a normal (low-orbit) mission to the ISS, the risk was approximately 1 in 300, but the Hubble telescope repair mission was flown at the higher orbital altitude of 560 km (350 mi) where the risk was initially calculated at a 1-in-185 (due in part to the 2009 satellite collision). A re-analysis with better debris numbers reduced the estimated risk to 1 in 221, and the mission went ahead.^[124]

Debris incidents continued on later Shuttle missions. During STS-115 in 2006 a fragment of circuit board bored a small hole through the radiator panels in Atlantis's cargo bay.^[125] On STS-118 in 2007 debris blew a bullet-like hole through Endeavour's radiator panel.^[126]

Mir

Impact wear was notable on Mir, the Soviet space station since it remained in space for long periods with its original solar module panels.^[127][128]

 

Debris impacts on Mir's solar panels degraded their performance. The damage is most noticeable on the panel on the right, which is facing the camera with a high degree of contrast. Extensive damage to the smaller panel below is due to impact with a Progress spacecraft.

International Space Station

The ISS also uses Whipple shielding to protect its interior from minor debris.^[129] However, exterior portions (notably its solar panels) cannot be protected easily. In 1989, the ISS panels were predicted to degrade approximately 0.23% in four years due to the "sandblasting" effect of impacts with small orbital debris.^[130] An avoidance maneuver is typically performed for the ISS if "there is a greater than one-in-10,000 chance of a debris strike".^[131] As of January 2014^[update], there have been sixteen maneuvers in the fifteen years the ISS had been in orbit.^[131] By 2019, over 1,400 meteoroid and orbital debris (MMOD) impacts had been recorded on the ISS.^[132]

As another method to reduce the risk to humans on board, ISS operational management asked the crew to shelter in the Soyuz on three occasions due to late debris-proximity warnings. In addition to the sixteen thruster firings and three Soyuz-capsule shelter orders, one attempted maneuver was not completed due to not having the several days' warning necessary to upload the maneuver timeline to the station's computer.^{[131][133][134]} A March 2009 event involved debris believed to be a 10 cm (3.9 in) piece of the Kosmos 1275 satellite.^[135] In 2013, the ISS operations management did not make a maneuver to avoid any debris, after making a record four debris maneuvers the previous year.^[131]

Kessler syndrome

Main article: Kessler syndrome

 

Growth of tracked objects in orbit and related events;^[136] efforts to manage outer space global commons have so far not reduced the debris or the growth of objects in orbit

The Kessler syndrome,^[137][138] proposed by NASA scientist Donald J. Kessler in 1978, is a theoretical scenario in which the density of objects in low Earth orbit (LEO) is high enough that collisions between objects could cause a cascade effect where each collision generates space debris that increases the likelihood of further collisions.^[139] He further theorized that one implication, if this were to occur, is that the distribution of debris in orbit could render space activities and the use of satellites in specific orbital ranges economically impractical for many generations.^[139]

The growth in the number of objects as a result of the late-1990s studies sparked debate in the space community on the nature of the problem and the earlier dire warnings. According to Kessler's 1991 derivation and 2001 updates,^[140] the LEO environment in the 1,000 km (620 mi) altitude range should be cascading. However, only one major satellite collision incident occurred: the 2009 satellite collision between Iridium 33 and Cosmos 2251. The lack of obvious short-term cascading has led to speculation that the original estimates overstated the problem.^[141] According to Kessler in 2010 however, a cascade may not be obvious until it is well advanced, which might take years.^[142]

On Earth

Main article: List of space debris fall incidents

 

Saudi officials inspect a crashed PAM-D module in January 2001.

Although most debris burns up in the atmosphere, larger debris objects can reach the ground intact. According to NASA, an average of one cataloged piece of debris has fallen back to Earth each day for the past 50 years. Despite their size, there has been no significant property damage from the debris.^[143] Burning up in the atmosphere may also contribute to atmospheric pollution.^[144] Numerous small cylindrical tanks from space objects have been found, designed to hold fuel or gasses.^[145]

Tracking and measurement

See also: Satellite tracking

Tracking from the ground

Radar and optical detectors such as lidar are the main tools for tracking space debris. Although objects under 10 cm (4 in) have reduced orbital stability, debris as small as 1 cm can be tracked,^[146][147] however determining orbits to allow re-acquisition is difficult. Most debris remain unobserved. The NASA Orbital Debris Observatory tracked space debris with a 3 m (10 ft) liquid mirror transit telescope.^[148] FM Radio waves can detect debris, after reflecting off them onto a receiver.^[149] Optical tracking may be a useful early-warning system on spacecraft.^[150]

The U.S. Strategic Command keeps a catalog of known orbital objects, using ground-based radar and telescopes, and a space-based telescope (originally to distinguish from hostile missiles). The 2009 edition listed about 19,000 objects.^[151] Other data come from the ESA Space Debris Telescope, TIRA,^[152] the Goldstone, Haystack,^[153] and EISCAT radars and the Cobra Dane phased array radar,^[154] to be used in debris-environment models like the ESA Meteoroid and Space Debris Terrestrial Environment Reference (MASTER).

Measurement in space

 

The Long Duration Exposure Facility (LDEF) is an important source of information on small-particle space debris.

Returned space hardware is a valuable source of information on the directional distribution and composition of the (sub-millimetre) debris flux. The LDEF satellite deployed by mission STS-41-C Challenger and retrieved by STS-32 Columbia spent 68 months in orbit to gather debris data. The EURECA satellite, deployed by STS-46 Atlantis in 1992 and retrieved by STS-57 Endeavour in 1993, was also used for debris study.^[155]

The solar arrays of Hubble were returned by missions STS-61 Endeavour and STS-109 Columbia, and the impact craters studied by the ESA to validate its models. Materials returned from Mir were also studied, notably the Mir Environmental Effects Payload (which also tested materials intended for the ISS^[156]).^[157][158]

Gabbard diagrams

A debris cloud resulting from a single event is studied with scatter plots known as Gabbard diagrams, where the perigee and apogee of fragments are plotted with respect to their orbital period. Gabbard diagrams of the early debris cloud prior to the effects of perturbations, if the data were available, are reconstructed. They often include data on newly observed, as yet uncatalogued fragments. Gabbard diagrams can provide important insights into the features of the fragmentation, the direction and point of impact.^[23][159]

Dealing with debris

An average of about one tracked object per day has been dropping out of orbit for the past 50 years,^[160] averaging almost three objects per day at solar maximum (due to the heating and expansion of the Earth's atmosphere), but one about every three days at solar minimum, usually five and a half years later.^[160] In addition to natural atmospheric effects, corporations, academics and government agencies have proposed plans and technology to deal with space debris, but as of November 2014^[update], most of these are theoretical, and there is no extant business plan for debris reduction.^[24]

A number of scholars have also observed that institutional factors—political, legal, economic, and cultural "rules of the game"—are the greatest impediment to the cleanup of near-Earth space. There is little commercial incentive to act, since costs are not assigned to polluters, though a number of technological solutions have been suggested.^[24] However, effects to date are limited. In the US, governmental bodies have been accused of backsliding on previous commitments to limit debris growth, "let alone tackling the more complex issues of removing orbital debris."^[161] The different methods for removal of space debris have been evaluated by the Space Generation Advisory Council, including French astrophysicist Fatoumata Kébé.^[162]

Growth mitigation

See also: Space traffic management

 

Spatial density of LEO space debris by altitude, according to 2011 a NASA report to the United Nations Office for Outer Space Affairs^[163]

 

Spatial density of space debris by altitude according to ESA MASTER-2001, without debris from the Chinese ASAT and 2009 collision events

As of the 2010s, several technical approaches to the mitigation of the growth of space debris are typically undertaken, yet no comprehensive legal regime or cost assignment structure is in place to reduce space debris in the way that terrestrial pollution has reduced since the mid-20th century.

To avoid excessive creation of artificial space debris, many—but not all—satellites launched to above-low-Earth-orbit are launched initially into elliptical orbits with perigees inside Earth's atmosphere so the orbit will quickly decay and the satellites then will destroy themselves upon reentry into the atmosphere. Other methods are used for spacecraft in higher orbits. These include passivation of the spacecraft at the end of its useful life; as well as the use of upper stages that can reignite to decelerate the stage to intentionally deorbit it, often on the first or second orbit following payload release; satellites that can, if they remain healthy for years, deorbit themselves from the lower orbits around Earth. Other satellites (such as many CubeSats) in low orbits below approximately 400 km (250 mi) orbital altitude depend on the energy-absorbing effects of the upper atmosphere to reliably deorbit a spacecraft within weeks or months.

Increasingly, spent upper stages in higher orbits—orbits for which low-delta-v deorbit is not possible, or not planned for—and architectures that support satellite passivation, at end of life are passivated at end of life. This removes any internal energy contained in the vehicle at the end of its mission or useful life. While this does not remove the debris of the now derelict rocket stage or satellite itself, it does substantially reduce the likelihood of the spacecraft destructing and creating many smaller pieces of space debris, a phenomenon that was common in many of the early generations of US and Soviet^[71] spacecraft.

Upper stage passivation (e.g. of Delta boosters^[28]) by releasing residual propellants reduces debris from orbital explosions; however even as late as 2011, not all upper stages implement this practice.^[164] SpaceX used the term "propulsive passivation" for the final maneuver of their six-hour demonstration mission (STP-2) of the Falcon 9 second stage for the US Air Force in 2019, but did not define what all that term encompassed.^[165]

With a "one-up, one-down" launch-license policy for Earth orbits, launchers would rendezvous with, capture and de-orbit a derelict satellite from approximately the same orbital plane.^[166] Another possibility is the robotic refueling of satellites. Experiments have been flown by NASA,^[167] and SpaceX is developing large-scale on-orbit propellant transfer technology.^[168]

Another approach to debris mitigation is to explicitly design the mission architecture to always leave the rocket second-stage in an elliptical geocentric orbit with a low-perigee, thus ensuring rapid orbital decay and avoiding long-term orbital debris from spent rocket bodies. Such missions will often complete the payload placement in a final orbit by the use of low-thrust electric propulsion or with the use of a small kick stage to circularize the orbit. The kick stage itself may be designed with the excess-propellant capability to be able to self-deorbit.^[169]

Self-removal

Although the ITU requires geostationary satellites to move to a graveyard orbit at the end of their lives, the selected orbital areas do not sufficiently protect GEO lanes from debris.^[60] Rocket stages (or satellites) with enough propellant may make a direct, controlled de-orbit, or if this would require too much propellant, a satellite may be brought to an orbit where atmospheric drag would cause it to eventually de-orbit. This was done with the French Spot-1 satellite, reducing its atmospheric re-entry time from a projected 200 years to about 15 by lowering its altitude from 830 km (516 mi) to about 550 km (342 mi).^[170][171]

The Iridium constellation – 95 communication satellites launched during the five-year period between 1997 and 2002 – provides a set of data points on the limits of self-removal. The satellite operator – Iridium Communications – remained operational over the two-decade life of the satellites (albeit with a company name change through a corporate bankruptcy during the period) and, by December 2019, had "completed disposal of the last of its 65 working legacy satellites."^[172] However, this process left 30 satellites with a combined mass of (20,400 kg (45,000 lb), or nearly a third of the mass of this constellation) in LEO orbits at approximately 700 km (430 mi) altitude, where self-decay is quite slow. Of these satellites, 29 simply failed during their time in orbit and were thus unable to self-deorbit, while one – Iridium 33 – was involved in the 2009 satellite collision with the derelict Russian military satellite Kosmos-2251.^[172] No contingency plan was laid for the removal of satellites that were unable to remove themselves. In 2019, the Iridium CEO, Matt Desch, said that Iridium would be willing to pay an active-debris-removal company to deorbit its remaining first-generation satellites if it were possible for an unrealistically low cost, say "US$10,000 per deorbit, but [he] acknowledged that price would likely be far below what a debris-removal company could realistically offer. 'You know at what point [it’s] a no-brainer, but [I] expect the cost is really in the millions or tens of millions, at which price I know it doesn’t make sense.'"^[172]

Passive methods of increasing the orbital decay rate of spacecraft debris have been proposed. Instead of rockets, an electrodynamic tether could be attached to a spacecraft at launch; at the end of its lifetime, the tether would be rolled out to slow the spacecraft.^[173] Other proposals include a booster stage with a sail-like attachment^[174] and a large, thin, inflatable balloon envelope.^[175]

In late December 2022, ESA successfully carried out a demonstration of a breaking sail-based satellite deorbiter, ADEO, which could be used by mitigation measures and is part of ESA's Zero Debris Initiative. Around one year earlier, China also tested a drag sail.^[176][177]

External removal

A variety of approaches have been proposed, studied, or had ground subsystems built to use other spacecraft to remove existing space debris. A consensus of speakers at a meeting in Brussels in October 2012, organized by the Secure World Foundation (a U.S. think tank) and the French International Relations Institute,^[178] reported that removal of the largest debris would be required to prevent the risk to spacecraft becoming unacceptable in the foreseeable future (without any addition to the inventory of dead spacecraft in LEO). To date in 2019, removal costs and legal questions about ownership and the authority to remove defunct satellites have stymied national or international action. Current space law retains ownership of all satellites with their original operators, even debris or spacecraft which are defunct or threaten active missions.

Multiple companies made plans in the late 2010s to conduct external removal on their satellites in mid-LEO orbits. For example, OneWeb planned to utilize onboard self-removal as "plan A" for satellite deorbiting at the end of life, but if a satellite were unable to remove itself within one year of end of life, OneWeb would implement "plan B" and dispatch a reusable (multi-transport mission) space tug to attach to the satellite at an already built-in capture target via a grappling fixture, to be towed to a lower orbit and released for re-entry.^[179][180]

Remotely controlled vehicles

A well-studied solution uses a remotely controlled vehicle to rendezvous with, capture, and return debris to a central station.^[181] One such system is Space Infrastructure Servicing, a commercially developed refueling depot and service spacecraft for communications satellites in geosynchronous orbit originally scheduled for a 2015 launch.^[182] The SIS would be able to "push dead satellites into graveyard orbits."^[183] The Advanced Common Evolved Stage family of upper stages is being designed with a high leftover-propellant margin (for derelict capture and de-orbit) and in-space refueling capability for the high delta-v required to de-orbit heavy objects from geosynchronous orbit.^[166] A tug-like satellite to drag debris to a safe altitude for it to burn up in the atmosphere has been researched.^[184] When debris is identified the satellite creates a difference in potential between the debris and itself, then using its thrusters to move itself and the debris to a safer orbit.

A variation of this approach is for the remotely controlled vehicle to rendezvous with debris, capture it temporarily to attach a smaller de-orbit satellite and drag the debris with a tether to the desired location. The "mothership" would then tow the debris-smallsat combination for atmospheric entry or move it to a graveyard orbit. One such system is the proposed Busek ORbital DEbris Remover (ORDER), which would carry over 40 SUL (satellite on umbilical line) de-orbit satellites and propellant sufficient for their removal.^[24]

On 7 January 2010 Star, Inc. reported that it received a contract from the Space and Naval Warfare Systems Command for a feasibility study of the ElectroDynamic Debris Eliminator (EDDE) propellantless spacecraft for space-debris removal.^[185] In February 2012 the Swiss Space Center at École Polytechnique Fédérale de Lausanne announced the Clean Space One project, a nanosatellite demonstration project for matching orbit with a defunct Swiss nanosatellite, capturing it and de-orbiting together.^[186] The mission has seen several evolutions to reach a pac-man inspired capture model.^[187] In 2013, Space Sweeper with Sling-Sat (4S), a grappling satellite which captures and ejects debris was studied.^{[188][needs update]} In 2022, a Chinese satellite, SJ-21, grabbed an unused satellite and "threw" it into an orbit with a lower risk for it to collide.^[189][190]

In December 2019, the European Space Agency awarded the first contract to clean up space debris. The €120 million mission dubbed ClearSpace-1 (a spinoff from the EPFL project) is slated to launch in 2025. It aims to remove a 100 kg VEga Secondary Payload Adapter (Vespa)^[191] left by Vega flight VV02 in an 800 km (500 mi) orbit in 2013. A "chaser" will grab the junk with four robotic arms and drag it down to Earth's atmosphere where both will burn up.^[192]

Laser methods

The laser broom uses a ground-based laser to ablate the front of the debris, producing a rocket-like thrust that slows the object. With continued application, the debris would fall enough to be influenced by atmospheric drag.^[193][194] During the late 1990s, the U.S. Air Force's Project Orion was a laser-broom design.^[195] Although a test-bed device was scheduled to launch on a Space Shuttle in 2003, international agreements banning powerful laser testing in orbit limited its use to measurements.^[196] The 2003 Space Shuttle Columbia disaster postponed the project and according to Nicholas Johnson, chief scientist and program manager for NASA's Orbital Debris Program Office, "There are lots of little gotchas in the Orion final report. There's a reason why it's been sitting on the shelf for more than a decade."^[197]

The momentum of the laser-beam photons could directly impart a thrust on the debris sufficient to move small debris into new orbits out of the way of working satellites. NASA research in 2011 indicates that firing a laser beam at a piece of space junk could impart an impulse of 1 mm (0.039 in) per second, and keeping the laser on the debris for a few hours per day could alter its course by 200 m (660 ft) per day.^[198] One drawback is the potential for material degradation; the energy may break up the debris, adding to the problem.^[199] A similar proposal places the laser on a satellite in Sun-synchronous orbit, using a pulsed beam to push satellites into lower orbits to accelerate their reentry.^[24] A proposal to replace the laser with an Ion Beam Shepherd has been made,^[200] and other proposals use a foamy ball of aerogel or a spray of water,^[201] inflatable balloons,^[202] electrodynamic tethers,^[203] electroadhesion,^[204] and dedicated anti-satellite weapons.^[205]

Nets

On 28 February 2014, Japan's Japan Aerospace Exploration Agency (JAXA) launched a test "space net" satellite. The launch was an operational test only.^[206] In December 2016 the country sent a space junk collector via Kounotori 6 to the ISS by which JAXA scientists experiment to pull junk out of orbit using a tether.^[207][208] The system failed to extend a 700-meter tether from a space station resupply vehicle that was returning to Earth.^[209][210] On 6 February the mission was declared a failure and leading researcher Koichi Inoue told reporters that they "believe the tether did not get released".^[211]

Since 2012, the European Space Agency has been working on the design of a mission to remove large space debris from orbit. The mission, e.Deorbit, is scheduled for launch during 2023 with an objective to remove debris heavier than 4,000 kilograms (8,800 lb) from LEO.^[212] Several capture techniques are being studied, including a net, a harpoon and a combination robot arm and clamping mechanism.^[213]

Harpoon

The RemoveDEBRIS mission plan is to test the efficacy of several ADR technologies on mock targets in low Earth orbit. In order to complete its planned experiments the platform is equipped with a net, a harpoon, a laser ranging instrument, a dragsail, and two CubeSats (miniature research satellites).^[214] The mission was launched on 2 April 2018.

National and international regulation

There is no international treaty minimizing space debris. However, the United Nations Committee on the Peaceful Uses of Outer Space (COPUOS) published voluntary guidelines in 2007,^[215] using a variety of earlier national regulatory attempts at developing standards for debris mitigation. As of 2008, the committee was discussing international "rules of the road" to prevent collisions between satellites.^[216] By 2013, a number of national legal regimes existed,^{[217][218][219]} typically instantiated in the launch licenses that are required for a launch in all spacefaring nations.^[220]

The U.S. issued a set of standard practices for civilian (NASA) and military (DoD and USAF) orbital-debris mitigation in 2001.^{[221][222][218]} The standard envisioned disposal for final mission orbits in one of three ways: 1) atmospheric reentry where even with "conservative projections for solar activity, atmospheric drag will limit the lifetime to no longer than 25 years after completion of mission;" 2) maneuver to a "storage orbit:" move the spacecraft to one of four very broad parking orbit ranges (2,000–19,700 km (1,200–12,200 mi), 20,700–35,300 km (12,900–21,900 mi), above 36,100 km (22,400 mi), or out of Earth orbit completely and into any heliocentric orbit; 3) "Direct retrieval: Retrieve the structure and remove it from orbit as soon as practicable after completion of mission."^[217] The standard articulated in option 1, which is the standard applicable to most satellites and derelict upper stages launched, has come to be known as the "25-year rule."^[223] The US updated the Orbital Debris Mitigation Standard Practices (ODMSP) in December 2019, but made no change to the 25-year rule even though "[m]any in the space community believe that the timeframe should be less than 25 years."^[224] There is no consensus however on what any new timeframe might be.^[224]

In 2002, the European Space Agency (ESA) worked with an international group to promulgate a similar set of standards, also with a "25-year rule" applying to most Earth-orbit satellites and upper stages. Space agencies in Europe began to develop technical guidelines in the mid-1990s, and ASI, UKSA, CNES, DLR and ESA signed a "European Code of Conduct" in 2006,^[219] which was a predecessor standard to the ISO international standard work that would begin the following year. In 2008, ESA further developed "its own "Requirements on Space Debris Mitigation for Agency Projects" which "came into force on 1 April 2008."^[219]

Germany and France have posted bonds to safeguard the property from debris damage.^{[clarification needed][225]} The "direct retrieval" option (option no. 3 in the US "standard practices" above) has rarely been done by any spacefaring nation (exception, USAF X-37) or commercial actor since the earliest days of spaceflight due to the cost and complexity of achieving direct retrieval, but the ESA has scheduled a 2025 demonstration mission (Clearspace-1) to do this with a single small 100 kg (220 lb) derelict upper stage at a projected cost of €120 million not including the launch costs.^[192]

By 2006, the Indian Space Research Organization (ISRO) had developed a number of technical means of debris mitigation (upper stage passivation, propellant reserves for movement to graveyard orbits, etc.) for ISRO launch vehicles and satellites, and was actively contributing to inter-agency debris coordination and the efforts of the UN COPUOS committee.^[226]

In 2007, the ISO began preparing an international standard for space-debris mitigation.^[227] By 2010, ISO had published "a comprehensive set of space system engineering standards aimed at mitigating space debris. [with primary requirements] defined in the top-level standard, ISO 24113." By 2017, the standards were nearly complete. However, these standards are not binding on any party by ISO or any international jurisdiction. They are simply available for use in any of a variety of voluntary ways. They "can be adopted voluntarily by a spacecraft manufacturer or operator, or brought into effect through a commercial contract between a customer and supplier, or used as the basis for establishing a set of national regulations on space debris mitigation."^[223]

The voluntary ISO standard also adopted the "25-year rule" for the "LEO protected region" below 2,000 km (1,200 mi) altitude that has been previously (and still is, as of 2019^[update]) used by the US, ESA, and UN mitigation standards, and identifies it as "an upper limit for the amount of time that a space system shall remain in orbit after its mission is completed. Ideally, the time to deorbit should be as short as possible (i.e., much shorter than 25 years)".^[223]

Holger Krag of the European Space Agency states that as of 2017 there is no binding international regulatory framework with no progress occurring at the respective UN body in Vienna.^[105]

Barriers

With the rapid development of the computer and digitalization industries, more countries and companies have engaged in space activities since the turn of the 20th century. The tragedy of the commons is an economic theory referring to a situation where maximizing self-interest through using a shared resource can finally lead to the resource degradation shared by all.^[228] Based on the theory, individuals’ rational action in space will finally lead to an irrational collective result: orbits are crowded with debris. As a common-pool resource, the Earth's orbits, especially LEO and GEO that accommodate most satellites, are nonexcludable and rivalry.^[229] To address the tragedy and ensure space sustainability, many technical approaches have been developed. And in terms of governance mechanisms, the top-down centralized one is less suitable to tackle the complex debris problem due to the increasing number of space actors.^[230] Instead, much evidence has proved that polycentric form of governance developed by Elinor Ostrom can work in space.^[231]

In the process of promoting the polycentric network, there are some existing barriers needed to be dealt with.

Incomplete data of space debris

As orbital debris is a global problem affecting both spacefaring and non-spacefaring nations, it is necessary to be handled in a worldwide context.^[228] Because of the complexity and dynamics of object movements like spacecrafts, debris, meteorites, etc., many countries and regions including the United States, Europe, Russia and China have developed their space situational awareness (SSA) to avoid potential threats in space or plan actions in advance.^[232] To a certain extent, SSA plays a role in tracking space debris. In order to build a powerful SSA system, there are two prerequisites: international cooperation and exchange of information and data.^[232] However, limitations still exist in spite of the substantially improving data quality over the past decades. Some space powers are not willing to share the information that they have collected, and those, such as the U.S., that have shared the data keep parts of it secret.^[233] Instead of joining in a coordinated way, a great deal of SSA programs and national databases run parallel to each other with some overlaps, hindering the formation of a collaborative monitoring system.^[233]

Some private actors are also trying to establish SSA systems. For example, the Space Data Association (SDA) formed in 2009 is a non-governmental entity. It currently consists of 21 global satellite operators and 4 executive members: Eutelsat, Inmarsat, Intelsat and SES. SDA is a non-profit platform, aiming to avoid radio interference and space collisions through pooling data from operators independently.^[232] Researchers suggest that it is essential to establish an international center for exchanging information on space debris because SSA networks do not completely equal debris tracking systems — the former ones focus more on active and threatening objects in space.^[234] And in terms of debris populations and defunct satellites, not very much operators have provided data.^[234]

In a polycentric governance network, a resource that cannot be holistically monitored is less possible to be well managed.^[233] Both insufficient transnational cooperation and information sharing bring resistance to addressing the debris problem. There is still a long way to go before building a global network that covers complete data and has strong interconnection and interoperability.

Insufficient participation of private actors

With the commercialization of satellites and space, the private sector is getting more interested in space activities. For example, SpaceX is planning to create a network of around 12,000 small satellites that can transmit high-speed internet to any place in the world.^[235] The proportion of commercial spacecrafts has increased from 4.6% in the 1980s to 55.6% in the 2010s.^[236] Despite the high participation rate of commercial entities, UN COPUOS once deliberately excluded them from having a voice in discussions unless being formally invited by a member state.^[230] Ostrom said that the involvement of all relevant stakeholders in the rule-design and implementation process is one of the critical elements of successful governance.^[237] The exclusion of private actors largely reduces the effectiveness of the committee's role in making collective-choice arrangements that reflect the interests of all space users.^[230]

The limited engagement of private actors slows down the process of addressing space debris to some degree.^[238] Ties existing between dissimilar stakeholders in the governance network offer access to diverse resources.^[239] Different competence among stakeholders can help allocate the tasks more reasonably. In that case, the expertise and experience of private operators are critical to help the world achieve space sustainability.^[238] The complementary strengths of different stakeholders enable the governance network to be more adaptable to changes and reach common goals more effectively.^[239] In recent years, many private actors have seen commercial opportunities of eliminating space debris. It is estimated that by 2022 the global market for debris monitoring and removal will generate a revenue of around $2.9 billion.^[240] For example, Astroscale has contracted with European and Japanese space agencies to develop the capacity of removing orbital debris.^[241] Despite that, they are still in small quantity compared to the number of those who have placed satellites in space. Privateer Space, a Hawaiian-based startup company started by American engineer Alex Fielding, space environmentalist Dr. Moriba Jah, and Apple co-founder Steve Wozniak, announced plans in September 2021 to launch hundreds of satellites into orbit in order to study space debris.^[242] However, the company stated it is in "stealth mode" and no such satellites have been launched.^[242]

Fortunately, the current space exploration is not completely driven by competition, and there still exists a chance for dialogues and cooperation among all stakeholders in both developed and developing countries, to reach an agreement on tackling space debris and assure an equitable and orderly exploration.^[243] Besides private actors, network governance does not necessarily exclude the states from playing a role. Instead, the different functions of states might promote the governance process.^[244] To improve the polycentric governance network of space debris, researchers suggest: encourage data-sharing among different national and organizational databases at the political level; develop shared standards for data collection systems to improve interoperability; enhance the participation of private actors through involving them in national and international discussions.^[233]

Environmental concerns

The continued practice of disposing of space debris on Earth in areas such as the spacecraft cemetery has raised environmental concerns.^[245] Klinger states that "the environmental geopolitics of Earth and outer space are inextricably linked by the spatial politics of privilege and sacrifice – among people, places, and institutions".^[245][246] Since 1971, 273 spacecraft and satellites have been directed to Point Nemo; this number includes the Mir Space Station (142 tonnes) and will include the International Space Station in 2024 (240 tonnes). In 2018, it was found that the water had 26 microplastic particles per cubic metre, meaning it is highly polluted.^[247] The prevalence of orbital debris has been likened to the terrestrial environmental phenomenon of "sacrifice zones," which are designated geographic regions with high levels of environmental degradation.

Since the 1960s, over three hundred rocket launch sites have been built globally.^[245] Among these launch sites, 17 hosted 90 launches in 2017 alone.^[245] Rocket launches affect local and global environments through the construction of necessary infrastructure, exposure of local environments to toxic residue and the dispersal of pollutants.^[245] Rockets are the only source of direct anthropogenic emissions into the stratosphere and emit ozone depleting substances such as nitrous oxide, hydrogen chloride and aluminium oxide; these substances can destroy 105 ozone molecules before depleting.^[245] Each launch showers an area concentrated within a kilometre with toxins, heavy metals, and acids.^[245] This results in localised regional acid rain, plant death, fish kills, and failed seed germination.^[245] Furthermore, studies on trace elements concentration in alligators, near NASA launch activities in Florida (USA), showed that over 50% of alligators had "greater than toxic levels" of trace elements in their liver.^[245] Similarly, research in Kazakhstan, Russia and China has found that unsymmetrical dimethylhydrazine (UDMH) has carcinogenic, mutagenic, convulsant, teratogenic, embryotoxic and DNA damaging effects on rodents living near the Baikonur Cosmodrome, Kazakhstan.^[248] It is unknown, however, at what trace concentrations these toxic effects manifest in humans or how it may bioaccumulate up the food chain.^[248] A lack of adequate resourcing to maintain safe, non-toxic environments makes these areas sacrifice zones and spaces of waste. The relative remoteness of these spaces makes them attractive launch sites, yet this "periphery" remain central to both their human and non-human inhabitants, who become "sacrificial".^{[249][250][245]}

Orbital debris as a question of environmental justice

An increase in anthropogenic activity in outer space has resulted in large amounts of physical pollution known as orbital debris.^[251] This has resulted in space becoming more and more congested due to this rapid increase.^[252] This increase in congestion threatens the orbital operations of nations and corporations alike.^[251] However, orbital debris also has an impact on the wider population through various means, such as potentially lethal debris falling from the sky,^[253] or orbital debris ruining night skies through light pollution.^[254] Environmental justice as described by the United States Environmental Protection Agency is the fair and meaningful involvement of all demographics in the development and implementation of environmental regulations and policies.^[255] Outer space can be seen as an environment like any other environment on Earth,^[256] making orbital debris a potential issue of environmental justice.

The idea of environmental injustice is also that the rights of those who have suffered environmental harm or have been disrupted and encroached upon by more powerful actors are protected.^[256] In the context of the space industry large space organisations and nations are the powerful actors and those who have suffered are public. Recent research shows that space exploration opens many questions about environmental justice.^[257] Environmental geopolitics of the earth and that of outer space are linked, particularly by the geopolitics of privilege from one party and sacrifice from another.^[256] They are also linked in the premise of environmental justice, this injustice can unfold on multiple scales such as emission from space launches, placement of outer space-related infrastructure and of course orbital debris in this case.^[256]

There is an argument that as well as viewing space as an environment space should also be viewed as a commons.^[258] If space is viewed as a commons then its resources need to be managed for the common good of all people. If not, then this poses a risk of injustice. By managing space as a resource that all nations have access to, and none can claim sovereignity over, outer space can be also understood as an example of a global commons. However, legally defining space as a common is challenging, as the idea of global commons is a social construct.^[252] Many space treaties include various phrases describing and defining the usage of outer space, including phrases such as "for the benefit of all people" and "shall be the providence of all mankind".^[259] However, none of these treaties provides an adequate framework for handling resources or resolving issues.^[259]

Governance frameworks for outer space have a very narrow and utilitarian view of outer space that looks at what they can gain from exploration.^[260]

At other celestial bodies

 

A piece of a thermal blanket that may have come from the descent stage of the Perseverance

 

Perseverance's backshell sitting upright on the surface of Jezero Crater

The issue of space debris has been raised as a mitigation challenge for missions around the Moon with the danger of increasing space debris around it.^[261][262]

In 2022, several elements of space debris were found on Mars, Perseverance's backshell was found on the surface of Jezero Crater,^[263] and a piece of a thermal blanket that may have come from the descent stage of the rover.^[264][265]

It is thought that on 4 March 2022, for the first time, human space debris – most likely a spent rocket body, Long March 3C third stage from the 2014 Chang'e 5 T1 mission – unintentionally hit the lunar surface, creating an unexpected double crater.^[266][267]

In popular culture

Until the End of the World (1991) is a French sci-fi drama set under the backdrop of an out-of-control Indian nuclear satellite, predicted to re-enter the atmosphere, threatening vast populated areas of the Earth.^[268]

Gravity, a 2013 survival film directed by Alfonso Cuaron, is about a disaster on a space mission caused by Kessler syndrome.^[269]

In season 1 of Love, Death & Robots (2019), episode 11, "Helping Hand", revolves around an astronaut being struck by a screw from space debris which knocks her off a satellite in orbit.^[270]

Manga and anime Planetes tells a story about a crew of Space Debris station that collects and disposes space debris.^[271]

See also

•  Space portal

• Category:Derelict satellites
• Interplanetary contamination
• Liability Convention
• List of large reentering space debris
• List of space debris producing events
• Long Duration Exposure Facility
• Near-Earth object
• Orbital Debris Co-ordination Working Group
• Project West Ford
• Satellite warfare
• Solar Maximum Mission
• Spacecraft cemetery
• Space domain awareness
• Space sustainability

References

Citations

1. "'We've left junk everywhere': why space pollution could be humanity's next big problem". The Guardian. 26 March 2016. from the original on 8 November 2019. Retrieved 28 December 2019.
2. Powell, Jonathan (2017). Cosmic Debris. Astronomers' Universe. Bibcode:2017cdwi.book.....P. doi:10.1007/978-3-319-51016-3. ISBN 978-3-319-51015-6.
3. "Guide to Space Debris". spaceacademy.net.au. from the original on 26 August 2018. Retrieved 13 August 2018.
4. Coase, Ronald (October 1960). "The Problem of Social Cost" (PDF). Journal of Law and Economics (PDF). The University of Chicago Press. 3: 1–44. doi:10.1086/466560. JSTOR 724810. S2CID 222331226. (PDF) from the original on 17 June 2012. Retrieved 13 December 2019.
5. Heyne, Paul; Boettke, Peter J.; Prychitko, David L. (2014). The Economic Way of Thinking (13th ed.). Pearson. pp. 227–28. ISBN 978-0-13-299129-2.
6. Muñoz-Patchen, Chelsea (2019). "Regulating the Space Commons: Treating Space Debris as Abandoned Property in Violation of the Outer Space Treaty". Chicago Journal of International Law. University of Chicago Law School. from the original on 13 December 2019. Retrieved 13 December 2019.
7. Werner, Debra (30 March 2018). "Preventing space pollution". Aerospace America. Retrieved 21 January 2023.
8. "Space debris by the numbers" 6 March 2019 at the Wayback Machine ESA, January 2019. Retrieved 5 March 2019
9. "Satellite Box Score" (PDF). Orbital Debris Quarterly News. Vol. 26, no. 4. NASA. November 2022. p. 14. (PDF) from the original on 24 December 2019. Retrieved 24 December 2019.
10. "UCS Satellite Database". Nuclear Weapons & Global Security. Union of Concerned Scientists. 1 May 2022. from the original on 20 December 2019. Retrieved 24 December 2019.
11. Clark, David (2006). The Elgar Companion to Development Studies. Edward Elgar Publishing. p. 668. ISBN 978-1-84376-475-5.
12. "The Threat of Orbital Debris and Protecting NASA Space Assets from Satellite Collisions" (PDF). Space Reference. 2009. Archived (PDF) from the original on 23 December 2015. Retrieved 18 December 2012.
13. Wiedemann, C. (2 April 2009). "Size distribution of NaK droplets for MASTER-2009". Proceedings of the 5th European Conference on Space Debris. 672: 17. Bibcode:2009ESASP.672E..17W.
14. A. Rossi et al, "Effects of the RORSAT NaK Drops on the Long Term Evolution of the Space Debris Population", University of Pisa, 1997.
15. Wiedemann, C.; Oswald, M.; Stabroth, S.; Klinkrad, H.; Vörsmann, P. (2005). "Size distribution of NaK droplets released during RORSAT reactor core ejection". Advances in Space Research. 35 (7): 1290–1295. Bibcode:2005AdSpR..35.1290W. doi:10.1016/j.asr.2005.05.056.
16. The Threat of Orbital Debris and Protecting NASA Space Assets from Satellite Collisions (PDF), Space Reference, 2009, archived (PDF) from the original on 23 December 2015, retrieved 18 December 2012
17. Harrington, Rebecca (5 February 2016). "The fastest object ever launched was a manhole cover – here's the story from the guy who shot it into space". Tech Insider - www.businessinsider.com Business Insider. Retrieved 11 June 2021.
18. Thomson, Iain (16 July 2015). "SCIENCEDid speeding American manhole cover beat Sputnik into space? Top boffin speaks to El Reg – How a nuke blast lid may have beaten Soviets by months". www.theregister.com. Retrieved 11 June 2021.
19. Hoots, Schumacher & Glover 2004, pp. 174–185.
20. T.S. Kelso, CelesTrak BBS: Historical Archives Archived 17 July 2012 at archive.today, 2-line elements dating to 1980
21. Schefter, p. 48.
22. Kaushal, Sourabh; Arora, Nishant (August 2010). "Space Debris and Its Mitigation". ISEC Space Elevator Conference. Retrieved 11 November 2022.
23. David Portree and Joseph Loftus. "Orbital Debris: A Chronology" 1 September 2000 at the Wayback Machine, NASA, 1999, p. 13.
24. Foust, Jeff (15 November 2014). "Companies Have Technologies, but Not Business Plans, for Orbital Debris Cleanup". Space News. Archived from the original on 6 December 2014. Retrieved 28 December 2019.
25. "NASA Orbital Debris Program". from the original on 3 November 2016. Retrieved 10 October 2016.
26. "Space Debris". NASA. 1 July 2019. Retrieved 4 December 2022.
27. Jessica (21 July 2017). "SMA Valves to Prevent In-Orbit Explosions" (Blog posting). European Space Agency. Retrieved 21 January 2023. Delta upper stage: There were several events for Delta second stages due to residual propellants until depletion burns were introduced in 1981.
28. Schefter 1982, p. 50.
29. See charts, Hoffman p. 7.
30. See chart, Hoffman p. 4.
31. In the time between the writing of Klinkrad (2006) Chapter 1 (earlier) and the Prolog (later) of Space Debris, Klinkrad changed the number from 8,500 to 13,000 – compare pp. 6 and ix.
32. Michael Hoffman, "It's getting crowded up there." Space News, 3 April 2009.
33. "Space Junk Threat Will Grow for Astronauts and Satellites" 9 April 2011 at the Wayback Machine, Fox News, 6 April 2011.
34. Stefan Lovgren, "Space Junk Cleanup Needed, NASA Experts Warn." 7 September 2009 at the Wayback Machine National Geographic News, 19 January 2006.
35. J.-C Liou and N. L. Johnson, "Risks in Space from Orbiting Debris" 1 June 2008 at the Wayback Machine, Science, Volume 311 Number 5759 (20 January 2006), pp. 340–341
36. Antony Milne, Sky Static: The Space Debris Crisis, Greenwood Publishing Group, 2002, ISBN 0-275-97749-8, p. 86.
37. Gleghorn 1995, p. 7.
38. Paul Marks, "Space debris threat to future launches" 26 April 2015 at the Wayback Machine, 27 October 2009.
39. Space junk at tipping point, says report 21 December 2017 at the Wayback Machine, BBC News, 2 September 2011
40. Clark, Phillip. . Archived from the original on 25 October 2021. Retrieved 7 February 2023.
41. "How many space debris objects are currently in orbit?" 18 May 2016 at the Wayback Machine ESA, July 2013. Retrieved 6 February 2016
42. "Satellite Box ScoreS" (PDF). Orbital Debris Quarterly News. Vol. 20, no. 3. NASA. July 2016. p. 8. (PDF) from the original on 11 October 2016. Retrieved 10 October 2016.
43. "UCS Satellite Database". Nuclear Weapons & Global Security. Union of Concerned Scientists. 11 August 2016. from the original on 3 June 2010. Retrieved 10 October 2016.
44. (PDF). nasa.gov. United Nations. 2009. ISBN 978-92-1-100813-5. Archived from the original (PDF) on 24 July 2009.
45. "Orbital Debris FAQ: How much orbital debris is currently in Earth orbit?" 25 August 2009 at the Wayback Machine NASA, March 2012. Retrieved 31 January 2016
46. Liou 2020.
47. Matt Ford, "Orbiting space junk heightens risk of satellite catastrophes." 5 April 2012 at the Wayback Machine Ars Technica, 27 February 2009.
48. Wertz, James; Everett, David; Puschell, Jeffrey (2011). Space mission engineering : the new SMAD. Hawthorne, CA: Microcosm Press. p. 139. ISBN 978-1881883159.
49. "What are hypervelocity impacts?" 9 August 2011 at the Wayback Machine ESA, 19 February 2009.
50. (PDF). NASA Orbital Debris Program Office. Archived from the original (PDF) on 20 October 2011. Retrieved 1 January 2012.
51. Donald J. Kessler (8 March 2009). . Archived from the original on 27 May 2010. Retrieved 22 September 2009.
52. Lisa Grossman, "NASA Considers Shooting Space Junk with Lasers" 22 February 2014 at the Wayback Machine, wired, 15 March 2011.
53. Nwankwo, Victor U. J; Denig, William; Chakrabarti, Sandip K.; Ajakaiye, Muyiwa P.; Fatokun1, Johnson; Akanni, Adeniyi W.; Raulin, Jean-Pierre; Correia, Emilia; Enoh, John E. (15 September 2020). "Atmospheric drag effects on modelled LEO satellites during the July 2000 Bastille Day event in contrast to an interval of geomagnetically quiet conditions". Annales Geophysicae. doi:10.5194/angeo-2020-33-rc2.
54. Kessler 1991, p. 65.
55. Heiner Klinkrad (2006). Space Debris: Models and Risk Analysis"]. Springer-Praxis. ISBN 3-540-25448-X. from the original on 12 May 2011. Retrieved 20 December 2009.
56. Brown, Gary; Harris, William (19 May 2000). "How Satellites Work". HowStuffWorks.com. Retrieved 21 January 2023.
57. Schildknecht, T.; Musci, R.; Flury, W.; Kuusela, J.; De Leon, J.; Dominguez Palmero, L. De Fatima (2005). "Optical observation of space debris in high-altitude orbits". Proceedings of the 4th European Conference on Space Debris (ESA SP-587). 18–20 April 2005. 587: 113. Bibcode:2005ESASP.587..113S.
58. CNES Symposium on Space Dynamics, 6–10 November 1989.
59. van der Ha, J. C.; Hechler, M. (1981). "The Collision Probability of Geostationary Satellites". 32nd International Astronautical Congress. 1981: 23. Bibcode:1981rome.iafcR....V.
60. Anselmo, L.; Pardini, C. (2000). "Collision Risk Mitigation in Geostationary Orbit". Space Debris. 2 (2): 67–82. Bibcode:2000SpDeb...2...67A. doi:10.1023/A:1021255523174. S2CID 118902351.
61. Gleghorn 1995, p. 86.
62. Gleghorn 1995, p. 152.
63. "The Olympus failure" ESA press release, 26 August 1993. 11 September 2007 at the Wayback Machine
64. "Notification for Express-AM11 satellite users in connection with the spacecraft failure" Russian Satellite Communications Company, 19 April 2006.
65. "Vanguard 1". from the original on 15 August 2019. Retrieved 4 October 2019.
66. "Vanguard I celebrates 50 years in space". Eurekalert.org. from the original on 5 June 2013. Retrieved 4 October 2013.
67. Johnson 1998, p. 62.
68. "Vanguard 50 years". from the original on 5 June 2013. Retrieved 4 October 2013.
69. "UCS Satellite Database". Retrieved 17 January 2023.
70. nasa,gov (13 April 2015). "Space Debris and Human Spacecraft". Retrieved 17 January 2023.
71. A. Rossi et al, "Effects of the RORSAT NaK Drops on the Long Term Evolution of the Space Debris Population", University of Pisa, 1997.
72. Gruss, Mike (6 May 2015). "DMSP-F13 Debris To Stay on Orbit for Decades". Space News. Retrieved 7 May 2015.
73. T.S. Kelso, CelesTrak [@TSKelso] (26 March 2016). "That brings the total so far for the NOAA 16 debris event to 275 pieces, with none having decayed from orbit" (Tweet). Retrieved 28 March 2016 – via Twitter.
74. George, Justin Paul (27 March 2019). "History of anti-satellite weapons: US tested 1st ASAT missile 60 years ago". This Week. Retrieved 21 January 2023. Russia: 20 co-orbital tests, 7 ground/air launched tests
75. Tellis, Ashley J. (15 April 2019), India's ASAT Test: An Incomplete Success, Carnegie Endowment for International Space, retrieved 21 January 2023
76. Johnson 1998, p. 63.
77. Tufte, Edward R (2013) [1990], Envisioning Information, Cheshire, CT: Graphics Press, p. 48, ISBN 978-0-9613921-1-6
78. Photo of tool bag floating near ISS Image on Wikipedia
79. Loftus, Joseph P. (1989). Orbital Debris from Upper-stage Breakup. AIAA. p. 227. ISBN 978-1-60086-376-9.
80. Some return to Earth intact, see this list 28 October 2009 at the Wayback Machine for examples.
81. "Spate of rocket breakups creates new space junk" 14 August 2014 at the Wayback Machine, NewScientist, 17 January 2007. Retrieved 16 March 2007.
82. "Rocket Explosion" 30 January 2008 at the Wayback Machine, Spaceweather.com, 22 February 2007. Retrieved 21 February 2007.
83. Ker Than, "Rocket Explodes Over Australia, Showers Space with Debris" 24 July 2008 at the Wayback Machine Space.com, 21 February 2007. Retrieved 21 February 2007.
84. "Recent Debris Events" 20 March 2007 at the Wayback Machine celestrak.com, 16 March 2007. Retrieved 14 July 2001.
85. . Zarya. 21 October 2012. Archived from the original on 10 October 2012. Retrieved 21 October 2012.
86. Liou, J-C (April 2011). "An Update on LEO Environment Remediation with Active Debris Removal" (PDF). Orbital Debris Quarterly News. 15 (2): 5. Retrieved 12 December 2022.
87. Foust, Jeff (13 October 2020). "Upper stages top list of most dangerous space debris". Space News. Retrieved 12 December 2022.
88. (PDF). Archived from the original (PDF) on 19 August 2019. Retrieved 22 May 2019.
89. "Rocket break up provides rare chance to test debris formation". from the original on 16 May 2019. Retrieved 22 May 2019.
90. "Confirmed breakup of Atlas 5 Centaur R/B (2018-079B, #43652) on April 6, 2019". from the original on 2 May 2019. Retrieved 22 May 2019.
91. Talbert, Tricia (2 December 2020). "New Data Confirm 2020 SO to be 1960s Upper Centaur Rocket Booster". NASA. Retrieved 16 January 2021.
92. "50-Year Old Rocket Stage Involved in Orbital Debris Event". Retrieved 13 December 2022.
93. Note that the list Schefter was presented only identified USSR ASAT tests.
94. Clayton Chun, "Shooting Down a Star: America's Thor Program 437, Nuclear ASAT, and Copycat Killers", Maxwell AFB Base, AL: Air University Press, 1999. ISBN 1-58566-071-X.
95. David Wright, "Debris in Brief: Space Debris from Anti-Satellite Weapons" 9 September 2009 at the Wayback Machine Union of Concerned Scientists, December 2007.
96. Leonard David, "China's Anti-Satellite Test: Worrisome Debris Cloud Circles Earth" 6 January 2011 at the Wayback Machine space.com, 2 February 2007.
97. "Fengyun 1C – Orbit Data" 18 March 2012 at the Wayback Machine Heavens Above.
98. Brian Burger, "NASA's Terra Satellite Moved to Avoid Chinese ASAT Debris" 13 May 2008 at the Wayback Machine, space.com. Retrieved 6 July 2007.
99. "Space Week: Is Space Junk Cluttering Up The Final Frontier". NPR.org. Retrieved 2 December 2020.
100. "Pentagon: Missile Scored Direct Hit on Satellite." 6 January 2018 at the Wayback Machine, npr.org, 21 February 2008.
101. Jim Wolf, "US satellite shootdown debris said gone from space" 14 July 2009 at the Wayback Machine, Reuters, 27 February 2009.
102. Chavez, Nicole; Pokharel, Sugam (28 March 2019). "India conducts successful anti-satellite missile operation, Prime Minister says". CNN. from the original on 28 March 2019. Retrieved 28 March 2019.
103. Berger, Eric (16 November 2021). "Russia acknowledges anti-satellite test, but says it's no big deal". Ars Technica. Retrieved 16 November 2021.
104. Berger, Eric (15 November 2021). "Russia may have just shot down its own satellite, creating a huge debris cloud [Updated]". Ars Technica. Retrieved 16 November 2021.
105. Seidler, Christoph (22 April 2017). "Problem Weltraumschrott: Die kosmische Müllkippe - SPIEGEL ONLINE - Wissenschaft". Der Spiegel. SPIEGEL ONLINE. from the original on 23 April 2017. Retrieved 22 April 2017.
106. Akahoshi, Y.; et al. (2008). "Influence of space debris impact on solar array under power generation". International Journal of Impact Engineering. 35 (12): 1678–1682. doi:10.1016/j.ijimpeng.2008.07.048.
107. "The Space Review: Regulating the void: In-orbit collisions and space debris". www.thespacereview.com. Retrieved 23 November 2020.
108. Kelley, Angelita (17 August 2014). Butler, James J; Xiong, Xiaoxiong (Jack); Gu, Xingfa (eds.). "Terra mission operations: Launch to the present (and beyond)" (PDF). Earth Observing Systems XIX. 9218: 92180M. Bibcode:2014SPIE.9218E..0MK. doi:10.1117/12.2061253. hdl:2060/20160008917. S2CID 32269938. (PDF) from the original on 2 December 2017. Retrieved 5 April 2018.
109. Fisher, Dominic (13 June 2017). Mission Status at Aura Science Team MOWG Meeting (PDF) (Report). Retrieved 13 December 2017.
110. . www.ssd.noaa.gov. Archived from the original on 7 June 2013. Retrieved 12 January 2022.
111. Becky Iannotta and Tariq Malik, "U.S. Satellite Destroyed in Space Collision" 17 May 2012 at the Wayback Machine, space.com, 11 February 2009
112. Paul Marks, "Satellite collision 'more powerful than China's ASAT test" 15 February 2009 at the Wayback Machine, New Scientist, 13 February 2009.
113. Listner, Michael (10 February 2012). . Space Safety Magazine. Archived from the original on 17 May 2019. Retrieved 14 December 2019.
114. yahoo.com, 11 February 2009. Retrieved 11 February 2009.
115. Becky Iannotta, "U.S. Satellite Destroyed in Space Collision" 17 May 2012 at the Wayback Machine, space.com, 11 February 2009. Retrieved 11 February 2009.
116. Leonard David (8 March 2013). "Russian Satellite Hit by Debris from Chinese Anti-Satellite Test". space.com. from the original on 11 March 2013. Retrieved 10 March 2013.
117. de Selding, Peter B. (22 November 2013). "Swarm Satellite Trio Launched To Study Earth's Magnetic Field - SpaceNews.com". Space News. Retrieved 21 January 2023.
118. "Space junk could take out a European satellite this week". CNET. from the original on 25 January 2017. Retrieved 25 January 2017.
119. Rob Matson, "Satellite Encounters" 6 October 2010 at the Wayback Machine Visual Satellite Observer's Home Page.
120. "STS-48 Space Shuttle Mission Report" 5 January 2016 at the Wayback Machine, NASA, NASA-CR-193060, October 1991.
121. Christiansen, E. L.; Hyden, J. L.; Bernhard, R. P. (2004). "Space Shuttle debris and meteoroid impacts". Advances in Space Research. 34 (5): 1097–1103. Bibcode:2004AdSpR..34.1097C. doi:10.1016/j.asr.2003.12.008.
122. Kelly, John. "Debris is Shuttle's Biggest Threat" 23 May 2009 at the Wayback Machine, space.com, 5 March 2005.
123. "Debris Danger". Aviation Week & Space Technology, Volume 169 Number 10 (15 September 2008), p. 18.
124. William Harwood, "Improved odds ease NASA's concerns about space debris" 19 June 2009 at the Wayback Machine, CBS News, 16 April 2009.
125. D. Lear et al, "Investigation of Shuttle Radiator Micro-Meteoroid & Orbital Debris Damage" 9 March 2012 at the Wayback Machine, Proceedings of the 50th Structures, Structural Dynamics, and Materials Conference, 4–7 May 2009, AIAA 2009–2361.
126. D. Lear, et al, "STS-118 Radiator Impact Damage" 13 August 2011 at the Wayback Machine, NASA
127. Smirnov, V.M.; et al. (2000). "Study of Micrometeoroid and Orbital Debris Effects on the Solar Panelson 'MIR'". Space Debris. 2 (1): 1–7. doi:10.1023/A:1015607813420. S2CID 118628073.
128. "Orbital Debris FAQ: How did the Mir space station fare during its 15-year stay in Earth orbit?" 25 August 2009 at the Wayback Machine, NASA, July 2009.
129. K Thoma et al, "New Protection Concepts for Meteoroid / Debris Shields" 9 April 2008 at the Wayback Machine, Proceedings of the 4th European Conference on Space Debris (ESA SP-587), 18–20 April 2005, p. 445.
130. Henry Nahra, "Effect of Micrometeoroid and Space Debris Impacts on the Space Station Freedom Solar Array Surfaces" 6 June 2011 at the Wayback Machine. Presented at the 1989 Spring Meeting of the Materials Research Society, 24–29 April 1989, NASA TR-102287.
131. de Selding, Peter B. (16 January 2014). "Space Station Required No Evasive Maneuvers in 2013 Despite Growing Debris Threat". Space News. Retrieved 17 January 2014.
132. Hyde, James L.; Christiansen, Eric L.; Lear, Dana M. (9–12 December 2019). Observations of MMOD Impact Damage to the ISS (PDF). First International Orbital Debris Conference. USRA. Retrieved 8 October 2021.
133. "Junk alert for space station crew" 18 March 2009 at the Wayback Machine, BBC News, 12 March 2009.
134. "International Space Station in debris scare" 31 October 2018 at the Wayback Machine, BBC News, 28 June 2011.
135. Haines, Lester. "ISS spared space junk avoidance manoeuvre" 10 August 2017 at the Wayback Machine, The Register, 17 March 2009.
136. Lawrence, A.; Rawls, M. L.; Jah, M.; Boley, A.; Di Vruno, F.; Garrington, S.; Kramer, M.; Lawler, S.; Lowenthal, J.; McDowell, J.; McCaughrean, M. (22 April 2022). "The Case for Space Environmentalism". Nature Astronomy. 6 (4): 428–435. arXiv:2204.10025. Bibcode:2022NatAs...6..428L. doi:10.1038/s41550-022-01655-6. S2CID 248300127.
137. . Articles.CNN.com. 3 May 2002. Archived from the original on 30 September 2012. Retrieved 17 March 2011.
138. Olsen, Steve (July 1998). "The Danger of Space Junk – 98.07". TheAtlantic.com. Retrieved 17 March 2011.
139. Kessler & Cour-Palais 1978.
140. Kessler & Anz-Meador 2001.
141. Gleghorn 1995.
142. Jan Stupl et al, "Debris-debris collision avoidance using medium power ground-based lasers", 2010 Beijing Orbital Debris Mitigation Workshop, 18–19 October 2010, see graph p. 4 9 March 2012 at the Wayback Machine
143. Brown, M. (2012). Orbital Debris Frequently Asked Questions. Retrieved from https://orbitaldebris.jsc.nasa.gov/faq.html 28 March 2019 at the Wayback Machine.
144. Brown, Mike (27 May 2021). "SpaceX Starlink: how it could kickstart an 'uncontrolled experiment'". Inverse. Retrieved 28 May 2021.
145. "History of Space and Launch Debris Recoveries". Paul D. Maley. 2 July 2022. Retrieved 31 July 2022.
146. D. Mehrholz et al;"Detecting, Tracking and Imaging Space Debris" 10 July 2009 at the Wayback Machine, ESA bulletin 109, February 2002.
147. Ben Greene, "Laser Tracking of Space Debris" 18 March 2009 at the Wayback Machine, Electro Optic Systems Pty
148. "Orbital debris: Optical Measurements" 15 February 2012 at the Wayback Machine, NASA Orbital Debris Program Office
149. Pantaleo, Rick. "Australian Scientists Track Space Junk by Listening to FM Radio". web. from the original on 4 December 2013. Retrieved 3 December 2013.
150. Englert, Christoph R.; Bays, J. Timothy; Marr, Kenneth D.; Brown, Charles M.; Nicholas, Andrew C.; Finne, Theodore T. (2014). "Optical orbital debris spotter". Acta Astronautica. 104 (1): 99–105. Bibcode:2014AcAau.104...99E. doi:10.1016/j.actaastro.2014.07.031.
151. Grant Stokes et al, , MIT Lincoln Laboratory. Retrieved 8 March 2006.
152. H. Klinkrad. (PDF). fas.org. Archived from the original (PDF) on 4 March 2016. Retrieved 8 March 2006., fas.org. |date-accessed=8 March 2006.
153. "MIT Haystack Observatory" 29 November 2004 at the Wayback Machine haystack.mit.edu. Retrieved 8 March 2006.
154. "AN/FPS-108 COBRA DANE." 5 February 2016 at the Wayback Machine fas.org. Retrieved 8 March 2006.
155. Darius Nikanpour, "Space Debris Mitigation Technologies" 19 October 2012 at the Wayback Machine, Proceedings of the Space Debris Congress, 7–9 May 2009.
156. "STS-76 Mir Environmental Effects Payload (MEEP)". NASA. March 1996. from the original on 18 April 2011. Retrieved 8 March 2011.
157. MEEP 5 June 2011 at the Wayback Machine, NASA, 4 April 2002. Retrieved 8 July 2011
158. "STS-76 Mir Environmental Effects Payload (MEEP)" 29 June 2011 at the Wayback Machine, NASA, March 1996. Retrieved 8 March 2011.
159. David Whitlock, "History of On-Orbit Satellite Fragmentations" 3 January 2006 at the Wayback Machine, NASA JSC, 2004
160. Johnson, Nicholas (5 December 2011). . audio file, @0:05:50-0:07:40. The Space Show. Archived from the original on 27 January 2012. Retrieved 8 December 2011.
161. Foust, Jeff (24 November 2014). "Industry Worries Government 'Backsliding' on Orbital Debris". Space News. Archived from the original on 8 December 2014. Retrieved 8 December 2014. Despite growing concern about the threat posed by orbital debris, and language in U.S. national space policy directing government agencies to study debris cleanup technologies, many in the space community worry that the government is not doing enough to implement that policy.
162. Northfield, Rebecca (20 June 2018). "Women of Nasa: past, present and future". eandt.theiet.org. from the original on 21 January 2019. Retrieved 20 January 2019.
163. "USA Space Debris Environment, Operations, and Policy Updates" (PDF). NASA. UNOOSA. Retrieved 3 March 2021.
164. Johnson, Nicholas (5 December 2011). . audio file, @1:03:05-1:06:20. The Space Show. Archived from the original on 27 January 2012. Retrieved 8 December 2011.
165. Eric Ralph (19 April 2019). "SpaceX's Falcon Heavy flies a complex mission for the Air Force in launch video". Teslarati. from the original on 25 August 2019. Retrieved 14 December 2019.
166. Frank Zegler and Bernard Kutter, "Evolving to a Depot-Based Space Transportation Architecture", AIAA SPACE 2010 Conference & Exposition, 30 August-2 September 2010, AIAA 2010–8638. 10 May 2013 at the Wayback Machine
167. . Archived from the original on 10 August 2011. Retrieved 30 July 2012.
168. Bergin, Chris (27 September 2016). "SpaceX reveals ITS Mars game changer via colonization plan". NASASpaceFlight.com. from the original on 28 September 2016. Retrieved 21 October 2016.
169. "Rocket Lab to capitalize on test flight success with first operational mission". 7 March 2018. from the original on 7 March 2018. Retrieved 14 March 2020.
170. Luc Moliner, "Spot-1 Earth Observation Satellite Deorbitation" 16 January 2011 at the Wayback Machine, AIAA, 2002.
171. "Spacecraft: Spot 3" 30 September 2011 at the Wayback Machine, agi, 2003
172. Caleb Henry (30 December 2019). "Iridium would pay to deorbit its 30 defunct satellites – for the right price". SpaceNews. Retrieved 2 January 2020.
173. Bill Christensen, "The Terminator Tether Aims to Clean Up Low Earth Orbit" 26 November 2009 at the Wayback Machine, space.com. Retrieved 8 March 2006.
174. Jonathan Amos, "How satellites could 'sail' home" 1 July 2009 at the Wayback Machine, BBC News, 3 May 2009.
175. "Safe And Efficient De-Orbit of Space Junk Without Making The Problem Worse". Space Daily. 3 August 2010. from the original on 14 October 2013. Retrieved 16 September 2013.
176. Young, Chris (9 February 2023). "ESA successfully deploys braking sail for deorbiting small satellites". interestingengineering.com. from the original on 9 February 2023. Retrieved 15 February 2023.
177. "Show Me Your Wings: Successful In-flight Demonstration of the ADEO Braking Sail". www.esa.int. from the original on 13 February 2023. Retrieved 15 February 2023.
178. de Selding, Peter B. (31 October 2012). "Experts: Active Removal Key To Countering Space Junk Threat". Space News. Retrieved 21 January 2023.
179. Kramer, Miriam (19 December 2019). "The big business of being a space janitor - Axios".
180. "OneWeb adopts 100% grappling". 12 December 2019. from the original on 13 December 2019. Retrieved 22 December 2019.
181. Erika Carlson et al, "Final design of a space debris removal system", NASA/CR-189976, 1990.
182. "Intelsat Picks MacDonald, Dettwiler and Associates Ltd. for Satellite Servicing" 12 May 2011 at the Wayback Machine, CNW Newswire, 15 March 2011. Retrieved 15 July 2011.
183. de Selding, Peter (3 March 2010). "MDA Designing In-orbit Servicing Spacecraft". Space News. Archived from the original on 5 January 2013. Retrieved 15 July 2011.
184. Schaub, H.; Sternovsky, Z. (2013). "Active Space Debris Charging for Contactless Electrostatic Disposal". Advances in Space Research. 53 (1): 110–118. Bibcode:2014AdSpR..53..110S. doi:10.1016/j.asr.2013.10.003.
185. "News" 27 March 2010 at the Wayback Machine, Star Inc. Retrieved 18 July 2011.
186. Cleaning up Earth's orbit: A Swiss satellite tackles space junk (Report). EPFL. 15 February 2012. from the original on 28 May 2013. Retrieved 3 April 2013.
187. "Space Debris Removal | Cleanspace One". Space Debris Removal | Cleanspace One. from the original on 2 December 2017. Retrieved 1 December 2017.
188. Jan, McHarg (10 August 2012). "Project aims to remove space debris". Phys.org. from the original on 5 October 2013. Retrieved 3 April 2013.
189. "Chinese 'space cleaner' spotted grabbing and throwing away old satellite | DW | 09.02.2022". Deutsche Welle (www.dw.com).
190. Gough, Evan. "A Chinese space tug just grappled a dead satellite". Universe Today / phys.org. Retrieved 12 February 2022.
191. "VV02 – Vega uses Vespa". www.esa.int. from the original on 17 October 2019. Retrieved 13 December 2019.
192. "European Space Agency to launch space debris collector in 2025". The Guardian. 9 December 2019. from the original on 9 December 2019. Retrieved 13 December 2019.
193. Jonathan Campbell, "Using Lasers in Space: Laser Orbital Debris Removal and Asteroid Deflection" 7 December 2010 at the Wayback Machine, Occasional Paper No. 20, Air University, Maxwell Air Force Base, December 2000.
194. Mann, Adam (26 October 2011). "Space Junk Crisis: Time to Bring in the Lasers". Wired Science. from the original on 29 October 2011. Retrieved 1 November 2011.
195. Ivan Bekey, "Project Orion: Orbital Debris Removal Using Ground-Based Sensors and Lasers.", Second European Conference on Space Debris, 1997, ESA-SP 393, p. 699.
196. Justin Mullins "A clean sweep: NASA plans to carry out a spot of housework.", New Scientist, 16 August 2000.
197. Tony Reichhardt, "Satellite Smashers" Archived 29 July 2012 at archive.today, Air & Space Magazine, 1 March 2008.
198. James Mason et al, "Orbital Debris-Debris Collision Avoidance" 9 November 2018 at the Wayback Machine, arXiv:1103.1690v2, 9 March 2011.
199. David K. Monroe. Space debris removalusing a high-power ground-basedlaser (Report). Sandia National Laboratories. Retrieved 30 March 2023.
200. C. Bombardelli and J. Peláez, "Ion Beam Shepherd for Contactless Space Debris Removal". Journal of Guidance, Control, and Dynamics, Vol. 34, No. 3, May–June 2011, pp 916–920. http://sdg.aero.upm.es/PUBLICATIONS/PDF/2011/AIAA-51832-628.pdf 9 March 2012 at the Wayback Machine
201. Daniel Michaels, "A Cosmic Question: How to Get Rid Of All That Orbiting Space Junk?" 23 October 2017 at the Wayback Machine, Wall Street Journal, 11 March 2009.
202. "Company floats giant balloon concept as solution to space mess" 27 September 2011 at the Wayback Machine, Global Aerospace Corp press release, 4 August 2010.
203. "Space Debris Removal" 16 August 2010 at the Wayback Machine, Star-tech-inc.com. Retrieved 18 July 2011.
204. Foust, Jeff (5 October 2011). "A Sticky Solution for Grabbing Objects in Space". MIT Technology Review. Archived from the original on 4 February 2013. Retrieved 7 October 2011.
205. Jason Palmer, "Space junk could be tackled by housekeeping spacecraft " 30 May 2018 at the Wayback Machine, BBC News, 8 August 2011
206. Roppolo, Michael. "Japan Launches Net Into Space to Help With Orbital Debris". CBS News. 28 February 2014
207. "Japan launching 'space junk' collector (Update)". from the original on 2 February 2017. Retrieved 24 January 2017.
208. "Japan launches 'space junk' collector". The Times of India. from the original on 8 February 2017. Retrieved 24 January 2017.
209. "Space cargo ship experiment to clean up debris hits snag". The Japan Times Online. 31 January 2017. from the original on 31 January 2017. Retrieved 2 February 2017.
210. "A Japanese Space Junk Removal Experiment Has Failed in Orbit". Space.com. February 2017. from the original on 1 February 2017. Retrieved 2 February 2017.
211. "Japan's troubled 'space junk' mission fails". from the original on 12 February 2017. Retrieved 12 February 2017.
212. "Definition of an Automated Vehicle with Autonomous Fail-Safe Reaction Behavior to Capture and De-orbit Envisat" (PDF). 7th European Conference on Space Debris. ESA. 21 April 2017. Retrieved 16 January 2023.
213. Biesbroek, 2012 "Introduction to e.Deorbit" 17 September 2014 at the Wayback Machine. e.deorbit symposium. 6 May 2014
214. Clark, Stephen (1 April 2018). "Eliminating space junk could take step toward reality with station cargo launch". Spaceflight Now. from the original on 8 April 2018. Retrieved 6 April 2018.
215. "UN Space Debris Mitigation Guidelines" 6 October 2011 at the Wayback Machine, UN Office for Outer Space Affairs, 2010.
216. Theresa Hitchens, "COPUOS Wades into the Next Great Space Debate" 26 December 2008 at the Wayback Machine, The Bulletin of the Atomic Scientists, 26 June 2008.
217. "U.S. Government Orbital Debris Mitigation Standard Practices" (PDF). United States Federal Government. (PDF) from the original on 16 February 2013. Retrieved 28 November 2013.
218. "Orbital Debris – Important Reference Documents." 20 March 2009 at the Wayback Machine, NASA Orbital Debris Program Office.
219. "Mitigating space debris generation". European Space Agency. 19 April 2013. from the original on 26 April 2013. Retrieved 13 December 2019.
220. "Compliance of Rocket Upper Stages in GTO with Space Debris Mitigation Guidelines". Space Safety Magazine. 18 July 2013. Retrieved 16 February 2016.
221. Foust, Jeff (9 December 2019). "U.S. government updates orbital debris mitigation guidelines". SpaceNews. Retrieved 14 December 2019. the first update of the guidelines since their publication in 2001, and reflect a better understanding of satellite operations and other technical issues that contribute to the growing population of orbital debris. ...[The new 2019 guidelines] did not address one of the biggest issues regarding debris mitigation: whether to reduce the 25-year timeframe for deorbiting satellites after the end of their mission. Many in the space community believe that timeframe should be less than 25 years
222. "U.S. Government Orbital Debris Mitigation Standard Practices" (PDF). United States Federal Government. (PDF) from the original on 5 April 2004. Retrieved 13 December 2019.
223. Stokes; et al. Flohrer, T.; Schmitz, F. (eds.). STATUS OF THE ISO SPACE DEBRIS MITIGATION STANDARDS (2017) (PDF). 7th European Conference on Space Debris, Darmstadt, Germany, 18–21 April 2017. ESA Space Debris Office. (PDF) from the original on 13 December 2019. Retrieved 13 December 2019.
224. Foust, Jeff (10 December 2019). "U.S. government updates orbital debris mitigation guidelines". SpaceNews. Retrieved 11 August 2022.
225. Howell, Elizabeth (28 April 2013). . Universe Today. Archived from the original on 5 March 2014.
226. Adimurthya, V.; Ganeshanb, A.S. (February 2006). . Acta Astronautica. 58 (3): 168–174. Bibcode:2006AcAau..58..168A. doi:10.1016/j.actaastro.2005.09.002. Archived from the original on 13 December 2019.
227. E A Taylor and J R Davey, "Implementation of debris mitigation using International Organization for Standardization (ISO) standards" 9 March 2012 at the Wayback Machine, Proceedings of the Institution of Mechanical Engineers: G, Volume 221 Number 8 (1 June 2007), pp. 987 – 996.
228. Taylor, Jared B. (2011). "Tragedy of the space commons: a market mechanism solution to the space debris problem". The Columbia Journal of Transnational Law. 50: 253–279.
229. Chaddha, Shane (2010). A Tragedy of the Space Commons? (Report). Rochester, NY. doi:10.2139/ssrn.1586643. SSRN 1586643.
230. Johnson-Freese, Joan; Weeden, Brian (27 January 2012). "Application of Ostrom's Principles for Sustainable Governance of Common-Pool Resources to Near-Earth Orbit". Global Policy. 3 (1): 72–81. doi:10.1111/j.1758-5899.2011.00109.x. ISSN 1758-5880.
231. Morin, Jean‐Frédéric; Richard, Benjamin (5 June 2021). "Astro‐Environmentalism: Towards a Polycentric Governance of Space Debris". Global Policy. 12 (4): 568–573. doi:10.1111/1758-5899.12950. ISSN 1758-5880. S2CID 236171500.
232. Kaiser, Stefan A. (2015). "Legal and policy aspects of space situational awareness". Space Policy. 31: 5–12. Bibcode:2015SpPol..31....5K. doi:10.1016/j.spacepol.2014.11.002. ISSN 0265-9646.
233. Lambach, Daniel; Wesel, Luca (2021). "Tackling the Space Debris Problem: A Global Commons Perspective". Proc. 8th European Conference on Space Debris.
234. Skinner, Mark A. (2017). "Orbital debris: What are the best near-term actions to take? A view from the field". Journal of Space Safety Engineering. 4 (2): 105–111. doi:10.1016/j.jsse.2017.02.002. ISSN 2468-8967.
235. Sheetz, Michael (10 August 2020). "SpaceX is manufacturing 120 Starlink internet satellites per month". CNBC. Retrieved 14 March 2022.
236. The Space Economy in Figures: How Space Contributes to the Global Economy. www.oecd-ilibrary.org. 2019. doi:10.1787/c5996201-en. ISBN 9789264696549. S2CID 242966859. Retrieved 14 March 2022.
237. Chow, Tiffany; Weeden, Brian C. (2013). "Engaging All Stakeholders in Space Sustainability Governance Initiatives" (PDF). swfound.org.
238. Williamson, Ray A. (2012). "Assuring the sustainability of space activities". Space Policy. 28 (3): 154–160. Bibcode:2012SpPol..28..154W. doi:10.1016/j.spacepol.2012.06.010. ISSN 0265-9646.
239. Evans, J.P. (2011). Environmental Governance. Hoboken: Taylor & Francis.
240. Research and Markets (2018). "Global Space Debris Monitoring and Removal Market 2018-2022 with Airbus, ASTROSCALE, Boeing, Lockheed Martin, Northrop Grumman & RSC Energia Dominating". www.prnewswire.com. Retrieved 14 March 2022.
241. Moore, Adrian; van Burken, Rebecca (2021). "As Commercial Space Travel Becomes Reality, Debris and Space Traffic Management Becomes More Important". Reason Foundation. Retrieved 14 March 2022.
242. Mike Wall (18 November 2021). "Steve Wozniak's startup Privateer plans to launch hundreds of satellites to study space debris". Space.com. Retrieved 28 April 2022.
243. Newman, Christopher J.; Williamson, Mark (2018). "Space Sustainability: Reframing the Debate". Space Policy. 46: 30–37. Bibcode:2018SpPol..46...30N. doi:10.1016/j.spacepol.2018.03.001. ISSN 0265-9646. S2CID 158678917.
244. Carlsson, Lars Gunnar; Sandström, Annica Charlotte (2007). "Network Governance of the Commons". International Journal of the Commons. 2 (1): 33－54. doi:10.18352/ijc.20. ISSN 1875-0281. S2CID 155049248.
245. Klinger, Julie Michelle (2021). "Environmental geopolitics and outer space". Geopolitics. 26 (3): 666–703. doi:10.1080/14650045.2019.1590340. S2CID 150443847.
246. Dunnett, Oliver; Klinger, Julie; Maclaren, Andrew; Lane, Maria; Sage, Daniel (2019). "Geographies of Outer Space: Progress and New Opportunities". Progress in Human Geography. 43 (2): 314–366. doi:10.1177/0309132517747727. S2CID 149382358.
247. "Point Nemo is the most remote oceanic spot – yet it's still awash with plastic". The Guardian. Retrieved 14 March 2022.
248. Kolumbayeva, S.; Begimbetova, D.; Shalakhmetova, T.; Saliev, T.; Lovinskaya, A. (2014). "Chromosonal Instability in rodents caused by pollution from Baikonur Cosmodrome". Ecotoxicology. 22 (7): 1283–1291. doi:10.1007/s10646-014-1271-1. PMID 24990120. S2CID 23785137.
249. Gorman, A. (2007). "La terre et l'espace: Rockets, prisons, protests and heritage in Australia and French Guiana". Archaeologies. 3 (2): 153–68. doi:10.1007/s11759-007-9017-9. S2CID 129180386.
250. Mitchell, S. T. (2017). "Constellations of inequality: Space, race, and utopia in Brazil". University of Chicago Press.
251. Hunter, Hannah; Nelson, Elizabeth (1 September 2021). "Out of Place in Outer Space?: Exploring Orbital Debris through Geographical Imaginations". Environment and Society. 12 (1): 227–245. doi:10.3167/ares.2021.120113. ISSN 2150-6779.
252. Schrogl, Kai-Uwe; Giannopapa, Christina; Antoni, Ntorina, eds. (2 December 2021), "Outer space as a global commons and the role of space law", A Research Agenda for Space Policy, Edward Elgar Publishing, doi:10.4337/9781800374744.00009, ISBN 978-1-80037-474-4, retrieved 13 March 2023
253. "Space Objects a Real Hazard to People, Property | Environmental Law Institute". www.eli.org. Retrieved 13 March 2023.
254. Robin George Andrews. "Satellites and junk are littering space and ruining our night skies". New Scientist. Retrieved 13 March 2023.
255. US EPA, OEJECR (3 November 2014). "Environmental Justice". www.epa.gov. Retrieved 13 March 2023.
256. Klinger, Julie Michelle (3 May 2021). "Environmental Geopolitics and Outer Space". Geopolitics. 26 (3): 666–703. doi:10.1080/14650045.2019.1590340. ISSN 1465-0045.
257. Timko, Peter; Korpershoek, Karlijn; Ojani, Chakad; Szolucha, Anna (June 2022). "Exploring the extraplanetary: Social studies of outer space". Anthropology Today. 38 (3): 9–12. doi:10.1111/1467-8322.12726. ISSN 0268-540X.
258. Sutch, Peter; Roberts, Peri (4 November 2019). "Outer space and neo-colonial injustice: Distributive justice and the continuous scramble for dominium". International Journal of Social Economics. 46 (11): 1291–1304. doi:10.1108/IJSE-03-2019-0152. ISSN 0306-8293.
259. 66th International Astronautical Congress, 2015. Paris, France: International Astronautical Federation, American Institute of Aeronautics and Astronautics. 2015. ISBN 978-1-5108-1893-4. OCLC 987913512.
260. Marino, Alessandra; Cheney, Thomas (February 2023). "Centring Environmentalism in Space Governance: Interrogating Dominance and Authority Through a Critical Legal Geography of Outer Space". Space Policy. 63: 101521. doi:10.1016/j.spacepol.2022.101521.
261. Carter, Jamie (27 February 2022). "As Chinese Rocket Strikes Moon This Week We Need To Act Now To Prevent New Space Junk Around The Moon Say Scientists". Forbes. Retrieved 9 April 2022.
262. Mann, Adam (15 July 2013). "Space: The Final Frontier of Environmental Disasters?". Wired. Wired. Retrieved 21 January 2023.
263. Lenberg, Tatum (29 April 2022). "New Photos of Martian Space Wreckage". Discovery. Discovery.com. Retrieved 21 January 2023.
264. Kooser, Amanda. "'Unexpected': NASA Mars Rover Finds Piece of Its Landing System Stuck on a Rock". CNET. Retrieved 3 August 2022.
265. Devlin, Hannah (16 June 2022). "Nasa rover sighting reignites fears about human space debris". the Guardian. Retrieved 21 January 2023.
266. Strickland, Ashley; Hunt, Katie. "New double crater seen on the moon after mystery rocket impact". CNN. Retrieved 13 July 2022.
267. Garner, Rob (23 June 2022). "Rocket Impact Site on Moon Seen by NASA's Lunar Reconnaissance Orbiter". NASA. Retrieved 13 July 2022.
268. Adams, Eric (21 April 2020). "This 30-Year-Old Sci-Fi Epic Is a Saga for Our Times". Culture. Wired. ISSN 1059-1028. Retrieved 19 June 2020.
269. Sinha-Roy, Piya (21 July 2013). "'Gravity' gets lift at Comic-Con as director Cuaron leaps into space". Reuters. Retrieved 9 June 2020.
270. Brady, Matt (3 July 2019). "Conservation of Momentum in Netflix's Love, Death & Robots". The Science Of. Retrieved 21 April 2021.
271. Foxe, Steve; Edgar, Sean; The Paste Comics Crew (6 January 2017). "Required Reading: 50 of the Best Sci-Fi Comics". Paste. from the original on 25 January 2022. Retrieved 25 January 2022.

Bibliography

• Gleghorn, George; et al. (1995). Orbital Debris: A Technical Assessment (PDF) (Report). National Academy of Sciences. ISBN 0-309-05125-8..
• Hoots, Felix; Schumacher, Paul Jr.; Glover, Robert A. (2004). "History of Analytical Orbit Modeling in the U.S. Space Surveillance System". Journal of Guidance, Control, and Dynamics. 27 (2): 174–185. Bibcode:2004JGCD...27..174H. doi:10.2514/1.9161.
• Johnson, Nicholas L. (1998). "Monitoring and Controlling Debris in Space". Scientific American. 279 (2): 62–67. Bibcode:1998SciAm.279b..62J. doi:10.1038/scientificamerican0898-62. JSTOR 26070599. Retrieved 21 January 2023..
• Kessler, Donald (1971). "Estimate of Particle Densities and Collision Danger for Spacecraft Moving Through the Asteroid Belt". Physical Studies of Minor Planets. NASA SP-267. 267: 595–605. Bibcode:1971NASSP.267..595K..
• Kessler, Donald; Cour-Palais, Burton (June 1978). (PDF). Journal of Geophysical Research. 81 (A6): 2637–46. Bibcode:1978JGR....83.2637K. doi:10.1029/JA083iA06p02637. Archived from the original (PDF) on 15 May 2011..
• Kessler, Donald (1981). (PDF). Journal of Spacecraft. 16 (4): 357–60. Bibcode:1981JSpRo..18..357K. doi:10.2514/3.57828. Archived from the original (PDF) on 14 July 2010..
• Kessler, Donald (December 1991). (PDF). Advances in Space Research. 11 (12): 63–66. Bibcode:1991AdSpR..11l..63K. doi:10.1016/0273-1177(91)90543-S. Archived from the original (PDF) on 14 July 2010..
• Kessler, Donald; Anz-Meador, Phillip (March 2001). "Critical Number of Spacecraft in Low Earth Orbit: Using Fragmentation Data to Evaluate the Stability of the Orbital Debris Environment" (PDF). Proceedings of the Third European Conference on Space Debris. Darmstadt Germany. Retrieved 21 January 2023..
• Kessler, Donald (8 March 2009). The Kessler Syndrome. Western University Canada. Retrieved 21 January 2023..
• Liou, J.-C. (14 January 2020). "Risks from Orbital Debris and Space Situational Awareness" (PDF). IAA Conference on Space Situational Awareness. Washington, D.C. Retrieved 21 January 2023..
• Schefter, Jim (July 1982). "The Growing Peril of Space Debris". Popular Science. Vol. 221, no. 1. pp. 48–51 – via Google Books..

Further reading

• , Center for Orbital and Reentry Debris Studies, Aerospace Corporation
• Committee for the Assessment of NASA's Orbital Debris Programs (2011). Limiting Future Collision Risk to Spacecraft: An Assessment of NASA's Meteoroid and Orbital Debris Programs. Washington, D.C.: National Research Council. ISBN 978-0-309-21974-7.
  • Klotz, Irene (1 September 2011). "Space junk reaching 'tipping point,' report warns". Reuters. Retrieved 2 September 2011. News item summarizing the above report
• Steven A. Hildreth and Allison Arnold. Threats to U.S. National Security Interests in Space: Orbital Debris Mitigation and Removal. Washington, D.C.: Congressional Research Service, 8 January 2014.
• David Leonard, "The Clutter Above", Bulletin of the Atomic Scientists, July/August 2005.
• Patrick McDaniel, "A Methodology for Estimating the Uncertainty in the Predicted Annual Risk to Orbiting Spacecraft from Current or Predicted Space Debris Population". National Defense University, 1997.
• "Interagency Report on Orbital Debris, 1995", National Science and Technology Council, November 1995.
• Nickolay Smirnov, Space Debris: Hazard Evaluation and Mitigation. Boca Raton, FL: CRC Press, 2002, ISBN 0-415-27907-0.
• Richard Talcott, "How We Junked Up Outer Space", Astronomy, Volume 36, Issue 6 (June 2008), pp. 40–43.
• "Technical report on space debris, 1999", United Nations, 2006. ISBN 92-1-100813-1.
• Robin Biesbroek (2015). Active Debris Removal in Space: How to Clean the Earth's Environment from Space Debris. CreateSpace. ISBN 978-1-5085-2918-7.
• Khatchadourian, Raffi, "The Trash Nebula: Millions of man-made artifacts are circling Earth. Will one of them cause a disaster?", 28 September 2020, pp. 44–52, 54–55. "By one estimate, there are a hundred million bits of debris that are a millimetre in size, a hundred million as small as a micron. We live in a corona of trash. [T]he problem, if ignored, could destroy all the satellites that orbit near the Earth – a loss that would be more acutely felt as humanity increasingly relied on space." (p. 47.)

External links

 

Wikimedia Commons has media related to Space debris.

• Sativew – Tracking Space Junk in real time
• NASA Orbital Debris Program Office
• ESA Space Debris Office 5 September 2012 at the Wayback Machine
• , documentary film
• EISCAT Space Debris during the international polar year
• Intro to mathematical modeling of space debris flux 28 February 2019 at the Wayback Machine
• SOCRATES: A free daily service predicting close encounters on orbit between satellites and debris orbiting Earth
• A summary of current space debris by type and orbit
• Space Junk Astronomy Cast episode No. 82, includes full transcript
• Space Debris Illustrated: The Problem in Pictures
• PACA: Space Debris
• The Threat of Orbital Debris and Protecting NASA Space Assets from Satellite Collisions
• Space Age Wasteland: Debris in Orbit Is Here to Stay; Scientific American; 2012
• United States Space Surveillance Network
• PATENDER: GMV’S Trailblazing low-gravity space-debris capture system
• Space Junk Infographic
• Stuff In Space
• Astria Graph