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Galileo (spacecraft)

Galileo was an American robotic space probe that studied the planet Jupiter and its moons, as well as the asteroids Gaspra and Ida. Named after the Italian astronomer Galileo Galilei, it consisted of an orbiter and an entry probe. It was delivered into Earth orbit on October 18, 1989, by Space Shuttle Atlantis, during STS-34. Galileo arrived at Jupiter on December 7, 1995, after gravitational assist flybys of Venus and Earth, and became the first spacecraft to orbit an outer planet.[4]

Galileo
Artist's concept of Galileo at Io with Jupiter in the background. In reality, the high-gain foldable antenna failed to deploy in flight.
NamesJupiter Orbiter Probe
Mission typeJupiter orbiter
OperatorNASA
COSPAR ID1989-084B
SATCAT no.20298
Websitesolarsystem.nasa.gov/galileo/
Mission duration
  • Planned: 8 years, 1 month, 19 days
  • Jupiter orbit: 7 years, 9 months, 13 days
  • Final: 13 years, 11 months, 3 days
Distance travelled4,631,778,000 km (2.88 billion mi)[1]
Spacecraft properties
Manufacturer
Launch mass
  • Total: 2,560 kg (5,640 lb)[2]
  • Orbiter: 2,220 kg (4,890 lb)[2]
  • Probe: 340 kg (750 lb)[2]
Dry mass
  • Orbiter: 1,880 kg (4,140 lb)[2]
  • Probe: 340 kg (750 lb)[2]
Payload mass
  • Orbiter: 118 kg (260 lb)[2]
  • Probe: 30 kg (66 lb)[2]
Power
  • Orbiter: 570 watts at launch,[2] 493 watts on arrival,[3] 410 watts at end-of-life
  • Probe: 730 watt-hours[2]
Start of mission
Launch dateOctober 18, 1989, 16:53:40 (1989-10-18UTC16:53:40) UTC
RocketSpace Shuttle Atlantis
STS-34/IUS
Launch siteKennedy LC-39B
Entered serviceDecember 8, 1995, 01:16 UTC SCET
End of mission
DisposalControlled entry into Jupiter
Decay dateSeptember 21, 2003, 18:57:18 (2003-09-21UTC18:57:19) UTC
Instruments
SSISolid-State Imager
NIMSNear-Infrared Mapping Spectrometer
UVSUltraviolet Spectrometer
PPRPhotopolarimeter-Radiometer
DDSDust Detector Subsystem
EPDEnergetic Particles Detector
HICHeavy Ion Counter
MAGMagnetometer
PLSPlasma Subsystem
PWSPlasma Wave Subsystem
 

The Jet Propulsion Laboratory built the Galileo spacecraft and managed the Galileo program for NASA. West Germany's Messerschmitt-Bölkow-Blohm supplied the propulsion module. NASA's Ames Research Center managed the atmospheric probe, which was built by Hughes Aircraft Company. At launch, the orbiter and probe together had a mass of 2,562 kg (5,648 lb) and stood 6.15 m (20.2 ft) tall.

Spacecraft are normally stabilized either by spinning around a fixed axis or by maintaining a fixed orientation with reference to the Sun and a star. Galileo did both. One section of the spacecraft rotated at 3 revolutions per minute, keeping Galileo stable and holding six instruments that gathered data from many different directions, including the fields and particles instruments.

Galileo was intentionally destroyed in Jupiter's atmosphere on September 21, 2003. The next orbiter to be sent to Jupiter was Juno, which arrived on July 5, 2016.

Development edit

Jupiter is the largest planet in the Solar System, with more than twice the mass of all the other planets combined.[5] Consideration of sending a probe to Jupiter began as early as 1959.[6] NASA's Scientific Advisory Group (SAG) for Outer Solar System Missions considered the requirements for Jupiter orbiters and atmospheric probes. It noted that the technology to build a heat shield for an atmospheric probe did not yet exist, and facilities to test one under the conditions found on Jupiter would not be available until 1980.[7] NASA management designated the Jet Propulsion Laboratory (JPL) as the lead center for the Jupiter Orbiter Probe (JOP) project.[8] The JOP would be the fifth spacecraft to visit Jupiter, but the first to orbit it, and the probe would be the first to enter its atmosphere.[9]

 
In the Vertical Processing Facility (VPF), Galileo is prepared for mating with the Inertial Upper Stage booster.

An important decision made at this time was to use a Mariner program spacecraft like that used for Voyager for the Jupiter orbiter, rather than a Pioneer. Pioneer was stabilized by spinning the spacecraft at 60 rpm, which gave a 360-degree view of the surroundings, and did not require an attitude control system. By contrast, Mariner had an attitude control system with three gyroscopes and two sets of six nitrogen jet thrusters. Attitude was determined with reference to the Sun and Canopus, which were monitored with two primary and four secondary sensors. There was also an inertial reference unit and an accelerometer. This allowed it to take high-resolution images, but the functionality came at a cost of increased weight. A Mariner weighed 722 kilograms (1,592 lb) compared to just 146 kilograms (322 lb) for a Pioneer.[10]

John R. Casani, who had headed the Mariner and Voyager projects, became the first project manager.[11] He solicited suggestions for a more inspirational name for the project, and the most votes went to "Galileo" after Galileo Galilei, the first person to view Jupiter through a telescope. His 1610 discovery of what is now known as the Galilean moons orbiting Jupiter was important evidence of the Copernican model of the solar system. It was also noted that the name was that of a spacecraft in the Star Trek television show. The new name was adopted in February 1978.[12]

The Jet Propulsion Laboratory built the Galileo spacecraft and managed the Galileo mission for NASA. West Germany's Messerschmitt-Bölkow-Blohm supplied the propulsion module. NASA's Ames Research Center managed the atmospheric probe, which was built by Hughes Aircraft Company.[2] At launch, the orbiter and probe together had a mass of 2,562 kg (5,648 lb) and stood 6.15 m (20.2 ft) tall.[2] Spacecraft are normally stabilized either by spinning around a fixed axis or by maintaining a fixed orientation with reference the Sun and a star; Galileo did both. One section of the spacecraft rotated at 3 revolutions per minute, keeping Galileo stable and holding six instruments that gathered data from many different directions, including the fields and particles instruments.[13] Back on the ground, the mission operations team used software containing 650,000 lines of code in the orbit sequence design process; 1,615,000 lines in the telemetry interpretation; and 550,000 lines of code in navigation.[2] All of the spacecraft components and spare parts received a minimum of 2,000 hours of testing. The spacecraft was expected to last for at least five years—long enough to reach Jupiter and perform its mission.[14]

 
Launch of Space Shuttle Atlantis on STS-34, carrying Galileo into Earth orbit

On December 19, 1985, it departed the JPL in Pasadena, California, on the first leg of its journey, a road trip to the Kennedy Space Center in Florida.[14][15] Due to the Space Shuttle Challenger disaster, the May launch date could not be met.[16] The mission was rescheduled to October 12, 1989. The Galileo spacecraft would be launched by the STS-34 mission in the Space Shuttle Atlantis.[17] As the launch date of Galileo neared, anti-nuclear groups, concerned over what they perceived as an unacceptable risk to the public's safety from the plutonium in the Galileo's radioisotope thermoelectric generators (RTGs) and General Purpose Heat Source (GPHS) modules, sought a court injunction prohibiting Galileo's launch.[18] RTGs were necessary for deep space probes because they had to fly distances from the Sun that made the use of solar energy impractical.[19]

The launch was delayed twice more: by a faulty main engine controller that forced a postponement to October 17, and then by inclement weather, which necessitated a postponement to the following day,[20] but this was not a concern since the launch window extended until November 21.[21] Atlantis finally lifted off at 16:53:40 UTC on October 18, and went into a 343-kilometer (213 mi) orbit.[20] Galileo was successfully deployed at 00:15 UTC on October 19.[16] Following the IUS burn, the Galileo spacecraft adopted its configuration for solo flight, and separated from the IUS at 01:06:53 UTC on October 19.[22] The launch was perfect, and Galileo was soon headed towards Venus at over 14,000 km/h (9,000 mph).[23] Atlantis returned to Earth safely on October 23.[20]

 
Galileo's main components

Command and Data Handling (CDH) edit

The CDH subsystem was actively redundant, with two parallel data system buses running at all times.[24] Each data system bus (a.k.a. string) was composed of the same functional elements, consisting of multiplexers (MUX), high-level modules (HLM), low-level modules (LLM), power converters (PC), bulk memory (BUM), data management subsystem bulk memory (DBUM), timing chains (TC), phase locked loops (PLL), Golay coders (GC), hardware command decoders (HCD) and critical controllers (CRC).[25]

The CDH subsystem was responsible for maintaining the following functions:

  1. decoding of uplink commands
  2. execution of commands and sequences
  3. execution of system-level fault-protection responses
  4. collection, processing, and formatting of telemetry data for downlink transmission
  5. movement of data between subsystems via a data system bus.[26]

The spacecraft was controlled by six RCA 1802 COSMAC microprocessor CPUs: four on the spun side and two on the despun side. Each CPU was clocked at about 1.6 MHz, and fabricated on sapphire (silicon on sapphire), which is a radiation-and static-hardened material ideal for spacecraft operation. This 8-bit microprocessor was the first low-power CMOS processor chip, similar to the 6502 that was being built into the Apple II desktop computer at that time.[27]

The Galileo Attitude and Articulation Control System (AACSE) was controlled by two Itek Advanced Technology Airborne Computers (ATAC), built using radiation-hardened 2901s. The AACSE could be reprogrammed in flight by sending the new program through the Command and Data Subsystem.[28] The attitude control system software was written in the HAL/S programming language,[29] which was also used in the Space Shuttle program.[30]

Memory capacity provided by each BUM was 16K of RAM, while the DBUMs each provided 8K of RAM. There were two BUMs and two DBUMs in the CDH subsystem and they all resided on the spun side of the spacecraft. The BUMs and DBUMs provided storage for sequences and contain various buffers for telemetry data and interbus communication. Every HLM and LLM was built up around a single 1802 microprocessor and 32K of RAM (for HLMs) or 16K of RAM (for LLMs). Two HLMs and two LLMs resided on the spun side while two LLMs were on the despun side. Thus, total memory capacity available to the CDH subsystem was 176K of RAM: 144K allocated to the spun side and 32K to the despun side.[31] Each HLM was responsible for the following functions:

  1. uplink command processing
  2. maintenance of the spacecraft clock
  3. movement of data over the data system bus
  4. execution of stored sequences (time-event tables)
  5. telemetry control
  6. error recovery including system fault-protection monitoring and response.[31]

Each LLM was responsible for the following functions:

  1. collect and format engineering data from the subsystems
  2. provide the capability to issue coded and discrete commands to spacecraft users
  3. recognize out-of-tolerance conditions on status inputs
  4. perform some system fault-protection functions.[31]

Propulsion edit

 
Propulsion module

The propulsion subsystem consisted of a 400 N (90 lbf) main engine and twelve 10 N (2.2 lbf) thrusters, together with propellant, storage and pressurizing tanks and associated plumbing. The 10 N thrusters were mounted in groups of six on two 2-meter (6.6 ft) booms. The fuel for the system was 925 kg (2,039 lb) of monomethylhydrazine and nitrogen tetroxide. Two separate tanks held another 7 kg (15 lb) of helium pressurant. The propulsion subsystem was developed and built by Messerschmitt-Bölkow-Blohm and provided by West Germany, the major international partner in Project Galileo.[27]

Electrical power edit

At the time, solar panels were not practical at Jupiter's distance from the Sun; the spacecraft would have needed a minimum of 65 square meters (700 sq ft) of panels. Chemical batteries would likewise be prohibitively large due to technological limitations. The solution was two radioisotope thermoelectric generators (RTGs) which powered the spacecraft through the radioactive decay of plutonium-238. The heat emitted by this decay was converted into electricity through the solid-state Seebeck effect. This provided a reliable and long-lasting source of electricity unaffected by the cold environment and high-radiation fields in the Jovian system.[27][32]

Each GPHS-RTG, mounted on a 5-meter long (16 ft) boom, carried 7.8 kilograms (17 lb) of 238Pu. Each RTG contained 18 separate heat source modules, and each module encased four pellets of plutonium(IV) oxide, a ceramic material resistant to fracturing.[32] The plutonium was enriched to about 83.5 percent plutonium-238.[33] The modules were designed to survive a range of potential accidents: launch vehicle explosion or fire, re-entry into the atmosphere followed by land or water impact, and post-impact situations. An outer covering of graphite provided protection against the structural, thermal, and eroding environments of a potential re-entry into Earth's atmosphere. Additional graphite components provided impact protection, while iridium cladding of the RTGs provided post-impact containment.[32] The RTGs produced about 570 watts at launch. The power output initially decreased at the rate of 0.6 watts per month and was 493 watts when Galileo arrived at Jupiter.[3]

Telecommunications edit

The spacecraft had a large high-gain antenna which failed to deploy while in space, so the low-gain antenna was used instead, although at slower data transfer speeds.[34]

Instruments edit

Scientific instruments to measure fields and particles were mounted on the spinning section of the spacecraft, together with the main antenna, power supply, the propulsion module and most of Galileo's computers and control electronics. The sixteen instruments, weighing 118 kg (260 lb) altogether, included magnetometer sensors mounted on an 11 m (36 ft) boom to minimize interference from the spacecraft; a plasma instrument for detecting low-energy charged particles and a plasma-wave detector to study waves generated by the particles; a high-energy particle detector; and a detector of cosmic and Jovian dust. It also carried the Heavy Ion Counter, an engineering experiment to assess the potentially hazardous charged particle environments the spacecraft flew through, and an extreme ultraviolet detector associated with the UV spectrometer on the scan platform.[2]

The despun section's instruments included the camera system; the near infrared mapping spectrometer to make multi-spectral images for atmospheric and moon surface chemical analysis; the ultraviolet spectrometer to study gases; and the photopolarimeter-radiometer to measure radiant and reflected energy. The camera system was designed to obtain images of Jupiter's satellites at resolutions 20 to 1,000 times better than Voyager's best, because Galileo flew closer to the planet and its inner moons, and because the more modern CCD sensor in Galileo's camera was more sensitive and had a broader color detection band than the vidicons of Voyager.[2]

Despun section edit

Solid-state imager (SSI) edit

 
Solid-state imager

The SSI was an 800-by-800-pixel charge-coupled device (CCD) camera. The optical portion of the camera was a modified flight spare of the Voyager narrow-angle camera; a Cassegrain telescope.[35] The CCD had radiation shielding a 10 mm (0.4 in) thick layer of tantalum surrounding the CCD except where the light enters the system. An eight-position filter wheel was used to obtain images at specific wavelengths. The images were then combined electronically on Earth to produce color images. The spectral response of the SSI ranged from about 400 to 1100 nm. The SSI weighed 29.7 kg (65 lb) and consumed, on average, 15 watts of power.[36][37]

Near-infrared mapping spectrometer (NIMS) edit

 
Near-infrared mapping spectrometer

The NIMS instrument was sensitive to 0.7-to-5.2-micrometer wavelength infrared light, overlapping the wavelength range of the SSI. NIMS used a 229 mm (9 in) aperture reflecting telescope. The spectrometer used a grating to disperse the light collected by the telescope. The dispersed spectrum of light was focused on detectors of indium, antimonide and silicon. NIMS weighed 18 kg (40 lb) and used 12 watts of power on average.[38][39]

Ultraviolet spectrometer / extreme ultraviolet spectrometer (UVS/EUV) edit

 
Ultraviolet spectrometer

The Cassegrain telescope of the UVS had a 250 mm (9.8 in) aperture. Both the UVS and EUV instruments used a ruled grating to disperse light for spectral analysis. Light then passed through an exit slit into photomultiplier tubes that produced pulses of electrons, which were counted and the results sent to Earth. The UVS was mounted on Galileo's scan platform. The EUV was mounted on the spun section. As Galileo rotated, EUV observed a narrow ribbon of space perpendicular to the spin axis. The two instruments combined weighed about 9.7 kg (21 lb) and used 5.9 watts of power.[40][41]

Photopolarimeter–radiometer (PPR) edit

The PPR had seven radiometry bands. One of these used no filters and observed all incoming radiation, both solar and thermal. Another band allowed only solar radiation through. The difference between the solar-plus-thermal and the solar-only channels gave the total thermal radiation emitted. The PPR also measured in five broadband channels that spanned the spectral range from 17 to 110 micrometers. The radiometer provided data on the temperatures of Jupiter's atmosphere and satellites. The design of the instrument was based on that of an instrument flown on the Pioneer Venus spacecraft. A 100 mm (4 in) aperture reflecting telescope collected light and directed it to a series of filters, and, from there, measurements were performed by the detectors of the PPR. The PPR weighed 5.0 kg (11.0 lb) and consumed about 5 watts of power.[42][43]

Spun section edit

Dust-detector subsystem (DDS) edit

 
Dust-detector subsystem

The dust-detector subsystem (DDS) was used to measure the mass, electric charge, and velocity of incoming particles. The masses of dust particles that the DDS could detect go from 10−16 to 10−7 grams. The speed of these small particles could be measured over the range of 1 to 70 kilometers per second (0.6 to 43.5 mi/s). The instrument could measure impact rates from 1 particle per 115 days (10 megaseconds) to 100 particles per second. Such data was used to help determine dust origin and dynamics within the magnetosphere. The DDS weighed 4.2 kg (9.3 lb) and used an average of 5.4 watts of power.[44][45]

Energetic-particles detector (EPD) edit

The energetic-particles detector (EPD) was designed to measure the numbers and energies of ions and electrons whose energies exceeded about 20 keV (3.2 fJ). The EPD could also measure the direction of travel of such particles and, in the case of ions, could determine their composition (whether the ion is oxygen or sulfur, for example). The EPD used silicon solid-state detectors and a time-of-flight detector system to measure changes in the energetic particle population at Jupiter as a function of position and time. These measurements helped determine how the particles got their energy and how they were transported through Jupiter's magnetosphere. The EPD weighed 10.5 kg (23 lb) and used 10.1 watts of power on average.[46][47]

Heavy-ion counter (HIC) edit

 
Heavy-ion counter

The HIC was, in effect, a repackaged and updated version of some parts of the flight spare of the Voyager cosmic-ray system. The HIC detected heavy ions using stacks of single crystal silicon wafers. The HIC could measure heavy ions with energies as low as 6 MeV (1 pJ) and as high as 200 MeV (32 pJ) per nucleon. This range included all atomic substances between carbon and nickel. The HIC and the EUV shared a communications link and, therefore, had to share observing time. The HIC weighed 8.0 kg (17.6 lb) and used an average of 2.8 watts of power.[48][49]

Magnetometer (MAG) edit

 
Magnetometer (stowed)

The magnetometer (MAG) used two sets of three sensors. The three sensors allowed the three orthogonal components of the magnetic field section to be measured. One set was located at the end of the magnetometer boom and, in that position, was about 11 m (36 ft) from the spin axis of the spacecraft. The second set, designed to detect stronger fields, was 6.7 m (22 ft) from the spin axis. The boom was used to remove the MAG from the immediate vicinity of Galileo to minimize magnetic effects from the spacecraft. However, not all these effects could be eliminated by distancing the instrument. The rotation of the spacecraft was used to separate natural magnetic fields from engineering-induced fields. Another source of potential error in measurement came from the bending and twisting of the long magnetometer boom. To account for these motions, a calibration coil was mounted rigidly on the spacecraft to generate a reference magnetic field during calibrations. The magnetic field at the surface of the Earth has a strength of about 50,000 nT. At Jupiter, the outboard (11 m) set of sensors could measure magnetic field strengths in the range from ±32 to ±512 nT, while the inboard (6.7 m) set was active in the range from ±512 to ±16,384 nT. The MAG experiment weighed 7.0 kg (15.4 lb) and used 3.9 watts of power.[50][51]

Plasma subsystem (PLS) edit

The PLS used seven fields of view to collect charged particles for energy and mass analysis. These fields of view covered most angles from 0 to 180 degrees, fanning out from the spin axis. The rotation of the spacecraft carried each field of view through a full circle. The PLS measured particles in the energy range from 0.9 to 52,000 eV (0.14 to 8,300 aJ). The PLS weighed 13.2 kg (29 lb) and used an average of 10.7 watts of power.[52][53]

Plasma-wave subsystem (PWS) edit

 
Plasma-wave subsystem

An electric dipole antenna was used to study the electric fields of plasmas, while two search coil magnetic antennas studied the magnetic fields. The electric dipole antenna was mounted at the tip of the magnetometer boom. The search coil magnetic antennas were mounted on the high-gain antenna feed. Nearly simultaneous measurements of the electric and magnetic field spectrum allowed electrostatic waves to be distinguished from electromagnetic waves. The PWS weighed 7.1 kg (16 lb) and used an average of 9.8 watts.[54][55]

Galileo entry probe edit

Galileo entry probe
 
Diagram of the atmospheric entry probe's instruments and subsystems
Mission typeLander / Atmospheric probe
OperatorNASA
COSPAR ID1989-084E
SATCAT no.20298 
Mission duration61.4 minutes
Spacecraft properties
ManufacturerHughes Aircraft Company
BOL mass340 kg (750 lb)
Start of mission
Launch dateOctober 18, 1989 (1989-10-18)
RocketSTS-34 piggybacking with Galileo orbiter
Launch siteKennedy Space Center, Launch Complex 39B
 
 
Inner Descent Module of the Galileo Entry Probe

The atmospheric probe was built by Hughes Aircraft Company's Space and Communications Group at its El Segundo, California plant.[56][57] It weighed 339 kilograms (747 lb) and was 86 centimeters (34 in) high.[2] Inside the probe's heat shield, the scientific instruments were protected from extreme heat and pressure during its high-speed journey into the Jovian atmosphere, entering at 48 kilometers per second (110,000 mph).[58] Temperatures reached around 16,000 °C (29,000 °F).[59] NASA built a special laboratory, the Giant Planet Facility, to simulate the heat load, which was similar to the convective and radiative heating experienced by an ICBM warhead reentering the atmosphere.[60][61]

Batteries edit

The probe's electronics were powered by 13 lithium sulfur dioxide batteries manufactured by Honeywell's Power Sources Center in Horsham, Pennsylvania. Each cell was the size of a D battery so existing manufacturing tools could be used.[62][63] They provided a nominal power output of about 7.2-ampere hours capacity at a minimal voltage of 28.05 volts.[64]

Scientific instruments edit

The probe included seven instruments for taking data on its plunge into Jupiter:[65][66]

Scientific instruments
Instrument Function Mass Power consumption Principal investigator Organizations
Atmospheric structure instrument Measuring temperature, pressure and deceleration 4.1 kg (9.0 lb) 6.3 W Alvin Seiff Ames Research Center and San Jose State University Foundation
Neutral mass spectrometer Analyze the gas composition of the atmosphere 13 kg (29 lb) 29 W Hasso Niemann Goddard Space Flight Center
Helium Abundance Detector An interferometer supporting atmospheric composition studies 1.4 kg (3.1 lb) 1.1 W Ulf von Zahn University of Bonn, University of Rostock
Nephelometer Cloud location and cloud-particle observations 4.8 kg (11 lb) 14 W Boris Ragent Ames Research Center and San Jose State University Foundation
Net-flux radiometer Measuring the difference between upward and downward radiant flux at each altitude 3.0 kg (6.6 lb) 7.0 W L. Sromovsky University of Wisconsin
Lightning and radio emission detector and energetic particles instrument Measuring light and radio emissions associated with lightning, and fluxes of protons, electrons, alpha particles and heavy ions 2.7 kg (6.0 lb) 2.3 W Louis Lanzerotti Bell Laboratories, University of Florida and Federal Republic of Germany
Radio equipment Measuring wind speeds and atmospheric absorption David Atkinson University of Idaho

In addition, the probe's heat shield contained instrumentation to measure ablation during descent.[67]

Termination edit

Lacking the fuel to escape Jupiter's gravity well, at the end of Galileo's life, the probe was deliberately crashed into Jupiter on September 21, 2003, to prevent forward contamination of possible life of Jupiter's moon Europa.[68]

Names edit

The Galileo Probe had COSPAR ID 1989-084E while the orbiter had id 1989-084B.[69] Names for the spacecraft include Galileo Probe or Jupiter Entry Probe abbreviated JEP.[70] The related COSPAR IDs of the Galileo mission were:[71]

  • 1989-084A STS 34
  • 1989-084B Galileo
  • 1989-084C IUS (Orbus 21)
  • 1989-084D IUS (Orbus 6E)
  • 1989-084E Galileo Probe

See also edit

Notes edit

  1. ^ "The Final Day on Galileo" (Press release). Jet Propulsion Laboratory. September 21, 2003. from the original on September 30, 2023.
  2. ^ a b c d e f g h i j k l m n o p q r s "Galileo Jupiter Arrival" (PDF) (Press Kit). NASA / Jet Propulsion Laboratory. December 1995.
  3. ^ a b Taylor, Cheung & Seo 2002, p. 86.
  4. ^ "Galileo – Overview". NASA Solar System Exploration. Retrieved December 7, 2021.
  5. ^ "In Depth | Jupiter". NASA Solar System Exploration. Retrieved October 27, 2020.
  6. ^ Meltzer 2007, pp. 9–10.
  7. ^ Meltzer 2007, pp. 29–30.
  8. ^ Meltzer 2007, pp. 32–33.
  9. ^ Dawson & Bowles 2004, pp. 190–191.
  10. ^ Meltzer 2007, pp. 30–32.
  11. ^ . NASA. Archived from the original on March 19, 2010. Retrieved October 28, 2020.
  12. ^ Meltzer 2007, p. 38.
  13. ^ "Galileo In Depth". NASA. Retrieved December 6, 2020.
  14. ^ a b Meltzer 2007, pp. 68–69.
  15. ^ Beyer, O'Connor & Mudgway 1992.
  16. ^ a b Meltzer 2007, p. 78.
  17. ^ Carr, Jeffrey (November 10, 1988). (PDF) (Press release). NASA. 88-049. Archived from the original (PDF) on February 25, 2017. Retrieved November 5, 2020.
  18. ^ Broad, William J. (October 10, 1989). "Groups Protest Use of Plutonium on Galileo". The New York Times. Retrieved November 4, 2020.
  19. ^ Sagan, Carl (October 9, 1989). . Archived from the original on January 26, 2021. Retrieved November 4, 2020.
  20. ^ a b c "Mission Archives: STS-34". NASA. February 18, 2010. Retrieved January 7, 2017.
  21. ^ Sawyer, Kathy (October 17, 1989). "Galileo Launch Nears". The Washington Post. Retrieved November 5, 2020.
  22. ^ "PDS: Mission Information". NASA. Retrieved November 9, 2020.
  23. ^ "Galileo Travels 292,500 Miles Toward Venus". The Washington Post. Retrieved November 5, 2020.
  24. ^ Siewiorek & Swarz 1998, p. 683.
  25. ^ Tomayko 1988, pp. 198–199.
  26. ^ Tomayko 1988, pp. 193–198.
  27. ^ a b c . RESA. Archived from the original on June 13, 2008.
  28. ^ Tomayko 1988, pp. 198–201.
  29. ^ Tomayko 1988, p. 199.
  30. ^ Tomayko 1988, p. 110.
  31. ^ a b c Tomayko 1988, pp. 190–198.
  32. ^ a b c . NASA. Archived from the original on April 11, 2010. Retrieved May 15, 2011.
  33. ^ Bennett, Hemler & Schock 1994, p. 4.
  34. ^ . .jpl.nasa.gov. Archived from the original on May 28, 2010. Retrieved May 15, 2011.
  35. ^ "Solid-State Imaging (SSI)". NASA. Retrieved November 19, 2020.
  36. ^ . NASA. Archived from the original on July 1, 2010. Retrieved May 15, 2011.
  37. ^ . NASA. Archived from the original on August 2, 2009.
  38. ^ . NASA. Archived from the original on May 28, 2010. Retrieved May 15, 2011.
  39. ^ . UCLA. Archived from the original on October 10, 1999.
  40. ^ . NASA. Archived from the original on June 5, 2010. Retrieved May 15, 2011.
  41. ^ . University of Colorado at Boulder. Archived from the original on August 14, 2010.
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  43. ^ . Lowell Observatory. Archived from the original on July 21, 2004.
  44. ^ . NASA. Archived from the original on June 19, 2010. Retrieved May 15, 2011.
  45. ^ . High Energy Stereoscopic System. Archived from the original on February 10, 2007. Retrieved December 10, 2012. DSI via Stuttgart University
  46. ^ . NASA. Archived from the original on June 21, 2010. Retrieved May 15, 2011.
  47. ^ "Galileo EPD". Johns Hopkins University Applied Physics Laboratory. Retrieved December 5, 2020.
  48. ^ . NASA. Archived from the original on July 2, 2010. Retrieved May 15, 2011.
  49. ^ . Caltech. Archived from the original on December 2, 2005. Retrieved December 5, 2020.
  50. ^ . NASA. Archived from the original on February 18, 2010. Retrieved May 15, 2011.
  51. ^ . UCLA. Archived from the original on July 21, 2004.
  52. ^ . NASA. Archived from the original on June 21, 2010. Retrieved May 15, 2011.
  53. ^ . University of Iowa. Archived from the original on February 10, 2007..
  54. ^ . NASA. Archived from the original on December 13, 2009. Retrieved May 15, 2011.
  55. ^ "Galileo PWS". University of Iowa. Retrieved December 5, 2020.
  56. ^ . Flightglobal. Archived from the original on January 12, 2012. Retrieved May 15, 2011.
  57. ^ "Galileo Arrives at Kennedy Space Center" (Press release). NASA. May 17, 1989. 1989-1242. Retrieved March 6, 2021.
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  59. ^ "In Depth | Galileo Probe". NASA Solar System Exploration.
  60. ^ Laub & Venkatapathy 2003, pp. 1–9.
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  62. ^ Meltzer 2007, p. 118.
  63. ^ Hofland, Stofel & Taenaka 1996, p. 9.
  64. ^ Blagdon 1980, p. 83.
  65. ^ Meltzer 2007, p. 122.
  66. ^ . NASA. Archived from the original on January 18, 2009.
  67. ^ Milos 1997, pp. 705–713.
  68. ^ "Galileo Plunges Into Jupiter". September 22, 2003. Retrieved February 10, 2022.
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  71. ^ "Space Launch 1989-084". Knihovna Akademie věd ČR. Retrieved December 3, 2018.

References edit

  • Badescu, Viorel; Zacny, Kris (2018). Outer Solar System: Prospective Energy and Material Resources. Springer. ISBN 978-3-319-73845-1. OCLC 1042249198.
  • Blagdon, L. (1980). "Galileo Lithium SO2". The 1979 Goddard Space Flight Center Battery Workshop (PDF). Goddard Space Flight Center: NASA. pp. 83–95. Retrieved March 7, 2021.
  • Beyer, P. E.; O'Connor, R. C.; Mudgway, D. J. (May 15, 1992). "Galileo Early Cruise, Including Venus, First Earth, and Gaspra Encounters" (PDF). The Telecommunications and Data Acquisition Report: 265–281. TDA Progress Report 42-109. Retrieved March 6, 2021.
  • Bennett, Gary L.; Hemler, Richard J.; Schock, Alfred (October 9–14, 1994). Development and Use of the Galileo and Ulysses Power Sources. 45th Congress of the International Astronautical Federation. Jerusalem, Israel. Retrieved December 7, 2020.
  • Dawson, Virginia; Bowles, Mark (2004). Taming Liquid Hydrogen: The Centaur Upper Stage Rocket (PDF). The NASA History Series. Washington, DC: NASA. SP-4230. Retrieved October 1, 2020.
  • Hofland, L. M.; Stofel, E. J.; Taenaka, R. K. (1996). "Galileo Probe Lithium-Sulfur Dioxide Cell Life Testing". Proceedings of 11th Annual Battery Conference on Applications and Advances. Long Beach, California. pp. 9–14. doi:10.1109/BCAA.1996.484963.
  • Laub, B.; Venkatapathy, E. (October 6–9, 2003). "Thermal Protection System Technology and Facility Needs for Demanding Future Planetary Missions". (PDF). Lisbon, Portugal: University of Idaho. pp. 1–9. Archived from the original (PDF) on January 8, 2007. Retrieved December 12, 2006.
  • Meltzer, Michael (2007). Mission to Jupiter: A History of the Galileo Project (PDF). The NASA History Series. Washington, DC: NASA. OCLC 124150579. SP-4231. Retrieved January 19, 2021.
  • Milos, Frank S. (1997). "Galileo Probe Heat Shield Ablation Experiment". Journal of Spacecraft and Rockets. 34 (6): 705–713. Bibcode:1997JSpRo..34..705M. doi:10.2514/2.3293. ISSN 1533-6794.
  • Ritter, H.; Mazoue, F.; Santovincenzo, A.; Atzei, A. (2006). "Jupiter Entry Probe Feasibility Study from the ESTEC CDF Team: Heat Flux Evaluation & TPS Definition". Thermal Protection Systems and Hot Structures. 631: 6. Bibcode:2006ESASP.631E...6R.
  • Siddiqi, Asif A. (2018). Beyond Earth: A Chronicle of Deep Space Exploration, 1958–2016 (PDF). The NASA History Series (second ed.). Washington, DC: NASA History Program Office. ISBN 978-1-62683-042-4. LCCN 2017059404. SP-4041. Retrieved October 29, 2020.
  • Siewiorek, Daniel; Swarz, Robert S. (1998). Reliable Computer Systems. Natick, Massachusetts: A K Peters. ISBN 1-56881-092-X. OCLC 245700546.
  • Taylor, Jim; Cheung, Kar-Ming; Seo, Dongae (July 2002). Galileo Telecommunications (PDF). DESCANSO Design and Performance Summary Series. Washington, DC: NASA. Retrieved November 15, 2020.
  • Tomayko, James E. (March 1988). Computers in Spaceflight: The NASA Experience (PDF) (Report). NASA History Office. Retrieved October 29, 2020.


External links edit

  • by NASA's Solar System Exploration
  • by NASA's Solar System Exploration
  • Galileo Satellite Image Mosaics by Arizona State University
  • Galileo image album by Kevin M. Gill
  • Early probe results report
  • Galileo Probe NASA Space Science Data Coordinated Archive

galileo, spacecraft, this, article, about, jupiter, probe, navigation, satellite, system, galileo, satellite, navigation, star, trek, shuttle, galileo, star, trek, galileo, american, robotic, space, probe, that, studied, planet, jupiter, moons, well, asteroids. This article is about the Jupiter probe For the navigation satellite system see Galileo satellite navigation For the Star Trek shuttle see Galileo Star Trek Galileo was an American robotic space probe that studied the planet Jupiter and its moons as well as the asteroids Gaspra and Ida Named after the Italian astronomer Galileo Galilei it consisted of an orbiter and an entry probe It was delivered into Earth orbit on October 18 1989 by Space Shuttle Atlantis during STS 34 Galileo arrived at Jupiter on December 7 1995 after gravitational assist flybys of Venus and Earth and became the first spacecraft to orbit an outer planet 4 GalileoArtist s concept of Galileo at Io with Jupiter in the background In reality the high gain foldable antenna failed to deploy in flight NamesJupiter Orbiter ProbeMission typeJupiter orbiterOperatorNASACOSPAR ID1989 084BSATCAT no 20298Websitesolarsystem wbr nasa wbr gov wbr galileo wbr Mission durationPlanned 8 years 1 month 19 days Jupiter orbit 7 years 9 months 13 days Final 13 years 11 months 3 daysDistance travelled4 631 778 000 km 2 88 billion mi 1 Spacecraft propertiesManufacturerJet Propulsion Laboratory 2 Messerschmitt Bolkow Blohm 2 General Electric 2 Hughes Aircraft Company 2 Launch massTotal 2 560 kg 5 640 lb 2 Orbiter 2 220 kg 4 890 lb 2 Probe 340 kg 750 lb 2 Dry massOrbiter 1 880 kg 4 140 lb 2 Probe 340 kg 750 lb 2 Payload massOrbiter 118 kg 260 lb 2 Probe 30 kg 66 lb 2 PowerOrbiter 570 watts at launch 2 493 watts on arrival 3 410 watts at end of life Probe 730 watt hours 2 Start of missionLaunch dateOctober 18 1989 16 53 40 1989 10 18UTC16 53 40 UTCRocketSpace Shuttle Atlantis STS 34 IUSLaunch siteKennedy LC 39BEntered serviceDecember 8 1995 01 16 UTC SCETEnd of missionDisposalControlled entry into JupiterDecay dateSeptember 21 2003 18 57 18 2003 09 21UTC18 57 19 UTCInstrumentsSSISolid State ImagerNIMSNear Infrared Mapping SpectrometerUVSUltraviolet SpectrometerPPRPhotopolarimeter RadiometerDDSDust Detector SubsystemEPDEnergetic Particles DetectorHICHeavy Ion CounterMAGMagnetometerPLSPlasma SubsystemPWSPlasma Wave SubsystemNASA Flagship Program Voyager programCassini Huygens The Jet Propulsion Laboratory built the Galileo spacecraft and managed the Galileo program for NASA West Germany s Messerschmitt Bolkow Blohm supplied the propulsion module NASA s Ames Research Center managed the atmospheric probe which was built by Hughes Aircraft Company At launch the orbiter and probe together had a mass of 2 562 kg 5 648 lb and stood 6 15 m 20 2 ft tall Spacecraft are normally stabilized either by spinning around a fixed axis or by maintaining a fixed orientation with reference to the Sun and a star Galileo did both One section of the spacecraft rotated at 3 revolutions per minute keeping Galileo stable and holding six instruments that gathered data from many different directions including the fields and particles instruments Galileo was intentionally destroyed in Jupiter s atmosphere on September 21 2003 The next orbiter to be sent to Jupiter was Juno which arrived on July 5 2016 Contents 1 Development 2 Command and Data Handling CDH 3 Propulsion 4 Electrical power 5 Telecommunications 6 Instruments 6 1 Despun section 6 1 1 Solid state imager SSI 6 1 2 Near infrared mapping spectrometer NIMS 6 1 3 Ultraviolet spectrometer extreme ultraviolet spectrometer UVS EUV 6 1 4 Photopolarimeter radiometer PPR 6 2 Spun section 6 2 1 Dust detector subsystem DDS 6 2 2 Energetic particles detector EPD 6 2 3 Heavy ion counter HIC 6 2 4 Magnetometer MAG 6 2 5 Plasma subsystem PLS 6 2 6 Plasma wave subsystem PWS 7 Galileo entry probe 7 1 Batteries 7 2 Scientific instruments 8 Termination 9 Names 10 See also 11 Notes 12 References 13 External linksDevelopment editMain article Galileo project For a chronological guide see Timeline of Galileo spacecraft Jupiter is the largest planet in the Solar System with more than twice the mass of all the other planets combined 5 Consideration of sending a probe to Jupiter began as early as 1959 6 NASA s Scientific Advisory Group SAG for Outer Solar System Missions considered the requirements for Jupiter orbiters and atmospheric probes It noted that the technology to build a heat shield for an atmospheric probe did not yet exist and facilities to test one under the conditions found on Jupiter would not be available until 1980 7 NASA management designated the Jet Propulsion Laboratory JPL as the lead center for the Jupiter Orbiter Probe JOP project 8 The JOP would be the fifth spacecraft to visit Jupiter but the first to orbit it and the probe would be the first to enter its atmosphere 9 nbsp In the Vertical Processing Facility VPF Galileo is prepared for mating with the Inertial Upper Stage booster An important decision made at this time was to use a Mariner program spacecraft like that used for Voyager for the Jupiter orbiter rather than a Pioneer Pioneer was stabilized by spinning the spacecraft at 60 rpm which gave a 360 degree view of the surroundings and did not require an attitude control system By contrast Mariner had an attitude control system with three gyroscopes and two sets of six nitrogen jet thrusters Attitude was determined with reference to the Sun and Canopus which were monitored with two primary and four secondary sensors There was also an inertial reference unit and an accelerometer This allowed it to take high resolution images but the functionality came at a cost of increased weight A Mariner weighed 722 kilograms 1 592 lb compared to just 146 kilograms 322 lb for a Pioneer 10 John R Casani who had headed the Mariner and Voyager projects became the first project manager 11 He solicited suggestions for a more inspirational name for the project and the most votes went to Galileo after Galileo Galilei the first person to view Jupiter through a telescope His 1610 discovery of what is now known as the Galilean moons orbiting Jupiter was important evidence of the Copernican model of the solar system It was also noted that the name was that of a spacecraft in the Star Trek television show The new name was adopted in February 1978 12 The Jet Propulsion Laboratory built the Galileo spacecraft and managed the Galileo mission for NASA West Germany s Messerschmitt Bolkow Blohm supplied the propulsion module NASA s Ames Research Center managed the atmospheric probe which was built by Hughes Aircraft Company 2 At launch the orbiter and probe together had a mass of 2 562 kg 5 648 lb and stood 6 15 m 20 2 ft tall 2 Spacecraft are normally stabilized either by spinning around a fixed axis or by maintaining a fixed orientation with reference the Sun and a star Galileo did both One section of the spacecraft rotated at 3 revolutions per minute keeping Galileo stable and holding six instruments that gathered data from many different directions including the fields and particles instruments 13 Back on the ground the mission operations team used software containing 650 000 lines of code in the orbit sequence design process 1 615 000 lines in the telemetry interpretation and 550 000 lines of code in navigation 2 All of the spacecraft components and spare parts received a minimum of 2 000 hours of testing The spacecraft was expected to last for at least five years long enough to reach Jupiter and perform its mission 14 nbsp Launch of Space Shuttle Atlantis on STS 34 carrying Galileo into Earth orbit On December 19 1985 it departed the JPL in Pasadena California on the first leg of its journey a road trip to the Kennedy Space Center in Florida 14 15 Due to the Space Shuttle Challenger disaster the May launch date could not be met 16 The mission was rescheduled to October 12 1989 The Galileo spacecraft would be launched by the STS 34 mission in the Space Shuttle Atlantis 17 As the launch date of Galileo neared anti nuclear groups concerned over what they perceived as an unacceptable risk to the public s safety from the plutonium in the Galileo s radioisotope thermoelectric generators RTGs and General Purpose Heat Source GPHS modules sought a court injunction prohibiting Galileo s launch 18 RTGs were necessary for deep space probes because they had to fly distances from the Sun that made the use of solar energy impractical 19 The launch was delayed twice more by a faulty main engine controller that forced a postponement to October 17 and then by inclement weather which necessitated a postponement to the following day 20 but this was not a concern since the launch window extended until November 21 21 Atlantis finally lifted off at 16 53 40 UTC on October 18 and went into a 343 kilometer 213 mi orbit 20 Galileo was successfully deployed at 00 15 UTC on October 19 16 Following the IUS burn the Galileo spacecraft adopted its configuration for solo flight and separated from the IUS at 01 06 53 UTC on October 19 22 The launch was perfect and Galileo was soon headed towards Venus at over 14 000 km h 9 000 mph 23 Atlantis returned to Earth safely on October 23 20 nbsp Galileo s main componentsCommand and Data Handling CDH editThe CDH subsystem was actively redundant with two parallel data system buses running at all times 24 Each data system bus a k a string was composed of the same functional elements consisting of multiplexers MUX high level modules HLM low level modules LLM power converters PC bulk memory BUM data management subsystem bulk memory DBUM timing chains TC phase locked loops PLL Golay coders GC hardware command decoders HCD and critical controllers CRC 25 The CDH subsystem was responsible for maintaining the following functions decoding of uplink commands execution of commands and sequences execution of system level fault protection responses collection processing and formatting of telemetry data for downlink transmission movement of data between subsystems via a data system bus 26 The spacecraft was controlled by six RCA 1802 COSMAC microprocessor CPUs four on the spun side and two on the despun side Each CPU was clocked at about 1 6 MHz and fabricated on sapphire silicon on sapphire which is a radiation and static hardened material ideal for spacecraft operation This 8 bit microprocessor was the first low power CMOS processor chip similar to the 6502 that was being built into the Apple II desktop computer at that time 27 The Galileo Attitude and Articulation Control System AACSE was controlled by two Itek Advanced Technology Airborne Computers ATAC built using radiation hardened 2901s The AACSE could be reprogrammed in flight by sending the new program through the Command and Data Subsystem 28 The attitude control system software was written in the HAL S programming language 29 which was also used in the Space Shuttle program 30 Memory capacity provided by each BUM was 16K of RAM while the DBUMs each provided 8K of RAM There were two BUMs and two DBUMs in the CDH subsystem and they all resided on the spun side of the spacecraft The BUMs and DBUMs provided storage for sequences and contain various buffers for telemetry data and interbus communication Every HLM and LLM was built up around a single 1802 microprocessor and 32K of RAM for HLMs or 16K of RAM for LLMs Two HLMs and two LLMs resided on the spun side while two LLMs were on the despun side Thus total memory capacity available to the CDH subsystem was 176K of RAM 144K allocated to the spun side and 32K to the despun side 31 Each HLM was responsible for the following functions uplink command processing maintenance of the spacecraft clock movement of data over the data system bus execution of stored sequences time event tables telemetry control error recovery including system fault protection monitoring and response 31 Each LLM was responsible for the following functions collect and format engineering data from the subsystems provide the capability to issue coded and discrete commands to spacecraft users recognize out of tolerance conditions on status inputs perform some system fault protection functions 31 Propulsion edit nbsp Propulsion module The propulsion subsystem consisted of a 400 N 90 lbf main engine and twelve 10 N 2 2 lbf thrusters together with propellant storage and pressurizing tanks and associated plumbing The 10 N thrusters were mounted in groups of six on two 2 meter 6 6 ft booms The fuel for the system was 925 kg 2 039 lb of monomethylhydrazine and nitrogen tetroxide Two separate tanks held another 7 kg 15 lb of helium pressurant The propulsion subsystem was developed and built by Messerschmitt Bolkow Blohm and provided by West Germany the major international partner in Project Galileo 27 Electrical power editAt the time solar panels were not practical at Jupiter s distance from the Sun the spacecraft would have needed a minimum of 65 square meters 700 sq ft of panels Chemical batteries would likewise be prohibitively large due to technological limitations The solution was two radioisotope thermoelectric generators RTGs which powered the spacecraft through the radioactive decay of plutonium 238 The heat emitted by this decay was converted into electricity through the solid state Seebeck effect This provided a reliable and long lasting source of electricity unaffected by the cold environment and high radiation fields in the Jovian system 27 32 Each GPHS RTG mounted on a 5 meter long 16 ft boom carried 7 8 kilograms 17 lb of 238Pu Each RTG contained 18 separate heat source modules and each module encased four pellets of plutonium IV oxide a ceramic material resistant to fracturing 32 The plutonium was enriched to about 83 5 percent plutonium 238 33 The modules were designed to survive a range of potential accidents launch vehicle explosion or fire re entry into the atmosphere followed by land or water impact and post impact situations An outer covering of graphite provided protection against the structural thermal and eroding environments of a potential re entry into Earth s atmosphere Additional graphite components provided impact protection while iridium cladding of the RTGs provided post impact containment 32 The RTGs produced about 570 watts at launch The power output initially decreased at the rate of 0 6 watts per month and was 493 watts when Galileo arrived at Jupiter 3 Telecommunications editMain article Galileo project High gain antenna problem The spacecraft had a large high gain antenna which failed to deploy while in space so the low gain antenna was used instead although at slower data transfer speeds 34 Instruments editScientific instruments to measure fields and particles were mounted on the spinning section of the spacecraft together with the main antenna power supply the propulsion module and most of Galileo s computers and control electronics The sixteen instruments weighing 118 kg 260 lb altogether included magnetometer sensors mounted on an 11 m 36 ft boom to minimize interference from the spacecraft a plasma instrument for detecting low energy charged particles and a plasma wave detector to study waves generated by the particles a high energy particle detector and a detector of cosmic and Jovian dust It also carried the Heavy Ion Counter an engineering experiment to assess the potentially hazardous charged particle environments the spacecraft flew through and an extreme ultraviolet detector associated with the UV spectrometer on the scan platform 2 The despun section s instruments included the camera system the near infrared mapping spectrometer to make multi spectral images for atmospheric and moon surface chemical analysis the ultraviolet spectrometer to study gases and the photopolarimeter radiometer to measure radiant and reflected energy The camera system was designed to obtain images of Jupiter s satellites at resolutions 20 to 1 000 times better than Voyager s best because Galileo flew closer to the planet and its inner moons and because the more modern CCD sensor in Galileo s camera was more sensitive and had a broader color detection band than the vidicons of Voyager 2 Despun section edit Solid state imager SSI edit nbsp Solid state imager The SSI was an 800 by 800 pixel charge coupled device CCD camera The optical portion of the camera was a modified flight spare of the Voyager narrow angle camera a Cassegrain telescope 35 The CCD had radiation shielding a 10 mm 0 4 in thick layer of tantalum surrounding the CCD except where the light enters the system An eight position filter wheel was used to obtain images at specific wavelengths The images were then combined electronically on Earth to produce color images The spectral response of the SSI ranged from about 400 to 1100 nm The SSI weighed 29 7 kg 65 lb and consumed on average 15 watts of power 36 37 Near infrared mapping spectrometer NIMS edit nbsp Near infrared mapping spectrometer The NIMS instrument was sensitive to 0 7 to 5 2 micrometer wavelength infrared light overlapping the wavelength range of the SSI NIMS used a 229 mm 9 in aperture reflecting telescope The spectrometer used a grating to disperse the light collected by the telescope The dispersed spectrum of light was focused on detectors of indium antimonide and silicon NIMS weighed 18 kg 40 lb and used 12 watts of power on average 38 39 Ultraviolet spectrometer extreme ultraviolet spectrometer UVS EUV edit nbsp Ultraviolet spectrometer The Cassegrain telescope of the UVS had a 250 mm 9 8 in aperture Both the UVS and EUV instruments used a ruled grating to disperse light for spectral analysis Light then passed through an exit slit into photomultiplier tubes that produced pulses of electrons which were counted and the results sent to Earth The UVS was mounted on Galileo s scan platform The EUV was mounted on the spun section As Galileo rotated EUV observed a narrow ribbon of space perpendicular to the spin axis The two instruments combined weighed about 9 7 kg 21 lb and used 5 9 watts of power 40 41 Photopolarimeter radiometer PPR edit The PPR had seven radiometry bands One of these used no filters and observed all incoming radiation both solar and thermal Another band allowed only solar radiation through The difference between the solar plus thermal and the solar only channels gave the total thermal radiation emitted The PPR also measured in five broadband channels that spanned the spectral range from 17 to 110 micrometers The radiometer provided data on the temperatures of Jupiter s atmosphere and satellites The design of the instrument was based on that of an instrument flown on the Pioneer Venus spacecraft A 100 mm 4 in aperture reflecting telescope collected light and directed it to a series of filters and from there measurements were performed by the detectors of the PPR The PPR weighed 5 0 kg 11 0 lb and consumed about 5 watts of power 42 43 Spun section edit Dust detector subsystem DDS edit nbsp Dust detector subsystem The dust detector subsystem DDS was used to measure the mass electric charge and velocity of incoming particles The masses of dust particles that the DDS could detect go from 10 16 to 10 7 grams The speed of these small particles could be measured over the range of 1 to 70 kilometers per second 0 6 to 43 5 mi s The instrument could measure impact rates from 1 particle per 115 days 10 megaseconds to 100 particles per second Such data was used to help determine dust origin and dynamics within the magnetosphere The DDS weighed 4 2 kg 9 3 lb and used an average of 5 4 watts of power 44 45 Energetic particles detector EPD edit The energetic particles detector EPD was designed to measure the numbers and energies of ions and electrons whose energies exceeded about 20 keV 3 2 fJ The EPD could also measure the direction of travel of such particles and in the case of ions could determine their composition whether the ion is oxygen or sulfur for example The EPD used silicon solid state detectors and a time of flight detector system to measure changes in the energetic particle population at Jupiter as a function of position and time These measurements helped determine how the particles got their energy and how they were transported through Jupiter s magnetosphere The EPD weighed 10 5 kg 23 lb and used 10 1 watts of power on average 46 47 Heavy ion counter HIC edit nbsp Heavy ion counter The HIC was in effect a repackaged and updated version of some parts of the flight spare of the Voyager cosmic ray system The HIC detected heavy ions using stacks of single crystal silicon wafers The HIC could measure heavy ions with energies as low as 6 MeV 1 pJ and as high as 200 MeV 32 pJ per nucleon This range included all atomic substances between carbon and nickel The HIC and the EUV shared a communications link and therefore had to share observing time The HIC weighed 8 0 kg 17 6 lb and used an average of 2 8 watts of power 48 49 Magnetometer MAG edit nbsp Magnetometer stowed The magnetometer MAG used two sets of three sensors The three sensors allowed the three orthogonal components of the magnetic field section to be measured One set was located at the end of the magnetometer boom and in that position was about 11 m 36 ft from the spin axis of the spacecraft The second set designed to detect stronger fields was 6 7 m 22 ft from the spin axis The boom was used to remove the MAG from the immediate vicinity of Galileo to minimize magnetic effects from the spacecraft However not all these effects could be eliminated by distancing the instrument The rotation of the spacecraft was used to separate natural magnetic fields from engineering induced fields Another source of potential error in measurement came from the bending and twisting of the long magnetometer boom To account for these motions a calibration coil was mounted rigidly on the spacecraft to generate a reference magnetic field during calibrations The magnetic field at the surface of the Earth has a strength of about 50 000 nT At Jupiter the outboard 11 m set of sensors could measure magnetic field strengths in the range from 32 to 512 nT while the inboard 6 7 m set was active in the range from 512 to 16 384 nT The MAG experiment weighed 7 0 kg 15 4 lb and used 3 9 watts of power 50 51 Plasma subsystem PLS edit The PLS used seven fields of view to collect charged particles for energy and mass analysis These fields of view covered most angles from 0 to 180 degrees fanning out from the spin axis The rotation of the spacecraft carried each field of view through a full circle The PLS measured particles in the energy range from 0 9 to 52 000 eV 0 14 to 8 300 aJ The PLS weighed 13 2 kg 29 lb and used an average of 10 7 watts of power 52 53 Plasma wave subsystem PWS edit nbsp Plasma wave subsystem An electric dipole antenna was used to study the electric fields of plasmas while two search coil magnetic antennas studied the magnetic fields The electric dipole antenna was mounted at the tip of the magnetometer boom The search coil magnetic antennas were mounted on the high gain antenna feed Nearly simultaneous measurements of the electric and magnetic field spectrum allowed electrostatic waves to be distinguished from electromagnetic waves The PWS weighed 7 1 kg 16 lb and used an average of 9 8 watts 54 55 Galileo entry probe editSee also Galileo project Atmospheric probe Galileo entry probe nbsp Diagram of the atmospheric entry probe s instruments and subsystemsMission typeLander Atmospheric probeOperatorNASACOSPAR ID1989 084ESATCAT no 20298 nbsp Mission duration61 4 minutesSpacecraft propertiesManufacturerHughes Aircraft CompanyBOL mass340 kg 750 lb Start of missionLaunch dateOctober 18 1989 1989 10 18 RocketSTS 34 piggybacking with Galileo orbiterLaunch siteKennedy Space Center Launch Complex 39B nbsp Inner Descent Module of the Galileo Entry Probe The atmospheric probe was built by Hughes Aircraft Company s Space and Communications Group at its El Segundo California plant 56 57 It weighed 339 kilograms 747 lb and was 86 centimeters 34 in high 2 Inside the probe s heat shield the scientific instruments were protected from extreme heat and pressure during its high speed journey into the Jovian atmosphere entering at 48 kilometers per second 110 000 mph 58 Temperatures reached around 16 000 C 29 000 F 59 NASA built a special laboratory the Giant Planet Facility to simulate the heat load which was similar to the convective and radiative heating experienced by an ICBM warhead reentering the atmosphere 60 61 Batteries edit The probe s electronics were powered by 13 lithium sulfur dioxide batteries manufactured by Honeywell s Power Sources Center in Horsham Pennsylvania Each cell was the size of a D battery so existing manufacturing tools could be used 62 63 They provided a nominal power output of about 7 2 ampere hours capacity at a minimal voltage of 28 05 volts 64 Scientific instruments edit The probe included seven instruments for taking data on its plunge into Jupiter 65 66 Scientific instruments Instrument Function Mass Power consumption Principal investigator Organizations Atmospheric structure instrument Measuring temperature pressure and deceleration 4 1 kg 9 0 lb 6 3 W Alvin Seiff Ames Research Center and San Jose State University Foundation Neutral mass spectrometer Analyze the gas composition of the atmosphere 13 kg 29 lb 29 W Hasso Niemann Goddard Space Flight Center Helium Abundance Detector An interferometer supporting atmospheric composition studies 1 4 kg 3 1 lb 1 1 W Ulf von Zahn University of Bonn University of Rostock Nephelometer Cloud location and cloud particle observations 4 8 kg 11 lb 14 W Boris Ragent Ames Research Center and San Jose State University Foundation Net flux radiometer Measuring the difference between upward and downward radiant flux at each altitude 3 0 kg 6 6 lb 7 0 W L Sromovsky University of Wisconsin Lightning and radio emission detector and energetic particles instrument Measuring light and radio emissions associated with lightning and fluxes of protons electrons alpha particles and heavy ions 2 7 kg 6 0 lb 2 3 W Louis Lanzerotti Bell Laboratories University of Florida and Federal Republic of Germany Radio equipment Measuring wind speeds and atmospheric absorption David Atkinson University of Idaho In addition the probe s heat shield contained instrumentation to measure ablation during descent 67 Termination editLacking the fuel to escape Jupiter s gravity well at the end of Galileo s life the probe was deliberately crashed into Jupiter on September 21 2003 to prevent forward contamination of possible life of Jupiter s moon Europa 68 Names editThe Galileo Probe had COSPAR ID 1989 084E while the orbiter had id 1989 084B 69 Names for the spacecraft include Galileo Probe or Jupiter Entry Probe abbreviated JEP 70 The related COSPAR IDs of the Galileo mission were 71 1989 084A STS 34 1989 084B Galileo 1989 084C IUS Orbus 21 1989 084D IUS Orbus 6E 1989 084E Galileo ProbeSee also editExploration of Jupiter List of missions to the outer planets Juno spacecraft Atmosphere of Jupiter List of spacecraft powered by non rechargeable batteriesNotes edit The Final Day on Galileo Press release Jet Propulsion Laboratory September 21 2003 Archived from the original on September 30 2023 a b c d e f g h i j k l m n o p q r s Galileo Jupiter Arrival PDF Press Kit NASA Jet Propulsion Laboratory December 1995 a b Taylor Cheung amp Seo 2002 p 86 Galileo Overview NASA Solar System Exploration Retrieved December 7 2021 In Depth Jupiter NASA Solar System Exploration Retrieved October 27 2020 Meltzer 2007 pp 9 10 Meltzer 2007 pp 29 30 Meltzer 2007 pp 32 33 Dawson amp Bowles 2004 pp 190 191 Meltzer 2007 pp 30 32 NASA s 50 Year Men and Women NASA Archived from the original on March 19 2010 Retrieved October 28 2020 Meltzer 2007 p 38 Galileo In Depth NASA Retrieved December 6 2020 a b Meltzer 2007 pp 68 69 Beyer O Connor amp Mudgway 1992 a b Meltzer 2007 p 78 Carr Jeffrey November 10 1988 Four New Shuttle Crews Named STS 32 STS 33 STS 34 STS 35 PDF Press release NASA 88 049 Archived from the original PDF on February 25 2017 Retrieved November 5 2020 Broad William J October 10 1989 Groups Protest Use of Plutonium on Galileo The New York Times Retrieved November 4 2020 Sagan Carl October 9 1989 Galileo To Launch or not to Launch Archived from the original on January 26 2021 Retrieved November 4 2020 a b c Mission Archives STS 34 NASA February 18 2010 Retrieved January 7 2017 Sawyer Kathy October 17 1989 Galileo Launch Nears The Washington Post Retrieved November 5 2020 PDS Mission Information NASA Retrieved November 9 2020 Galileo Travels 292 500 Miles Toward Venus The Washington Post Retrieved November 5 2020 Siewiorek amp Swarz 1998 p 683 Tomayko 1988 pp 198 199 Tomayko 1988 pp 193 198 a b c Galileo Engineering RESA Archived from the original on June 13 2008 Tomayko 1988 pp 198 201 Tomayko 1988 p 199 Tomayko 1988 p 110 a b c Tomayko 1988 pp 190 198 a b c What s in an RTG NASA Archived from the original on April 11 2010 Retrieved May 15 2011 Bennett Hemler amp Schock 1994 p 4 Galileo FAQ Galileo s Antennas jpl nasa gov Archived from the original on May 28 2010 Retrieved May 15 2011 Solid State Imaging SSI NASA Retrieved November 19 2020 SSI Solid State Imaging NASA Archived from the original on July 1 2010 Retrieved May 15 2011 SSI Imaging Team NASA Archived from the original on August 2 2009 NIMS Near Infrared Mapping Spectrometer NASA Archived from the original on May 28 2010 Retrieved May 15 2011 NIMS Team UCLA Archived from the original on October 10 1999 EUVS Extreme Ultraviolet Spectrometer NASA Archived from the original on June 5 2010 Retrieved May 15 2011 EUV Team University of Colorado at Boulder Archived from the original on August 14 2010 PPR Photopolarimeter Radiometer NASA Archived from the original on June 14 2010 Retrieved May 15 2011 PPR Team Lowell Observatory Archived from the original on July 21 2004 DDS Dust Detector Subsystem NASA Archived from the original on June 19 2010 Retrieved May 15 2011 Cosmic Dust Messengers from Distant Worlds High Energy Stereoscopic System Archived from the original on February 10 2007 Retrieved December 10 2012 DSI via Stuttgart University EPD Energetic Particles Detector NASA Archived from the original on June 21 2010 Retrieved May 15 2011 Galileo EPD Johns Hopkins University Applied Physics Laboratory Retrieved December 5 2020 HIC Heavy Ion Counter NASA Archived from the original on July 2 2010 Retrieved May 15 2011 HIC Team Caltech Archived from the original on December 2 2005 Retrieved December 5 2020 MAG Magnetometer NASA Archived from the original on February 18 2010 Retrieved May 15 2011 MAG Team UCLA Archived from the original on July 21 2004 PLS Plasma Subsystem NASA Archived from the original on June 21 2010 Retrieved May 15 2011 PLS Team University of Iowa Archived from the original on February 10 2007 PWS Plasma Wave Subsystem NASA Archived from the original on December 13 2009 Retrieved May 15 2011 Galileo PWS University of Iowa Retrieved December 5 2020 Hughes Science Scope Press Release and Advertisement Flightglobal Archived from the original on January 12 2012 Retrieved May 15 2011 Galileo Arrives at Kennedy Space Center Press release NASA May 17 1989 1989 1242 Retrieved March 6 2021 Isbell Douglas Morse David January 22 1996 Galileo Probe Science Results JPL Retrieved March 4 2016 In Depth Galileo Probe NASA Solar System Exploration Laub amp Venkatapathy 2003 pp 1 9 Bernard Laub October 19 2004 Development of New Ablative Thermal Protection Systems TPS NASA Ames Research Center Archived from the original on October 19 2006 Retrieved December 12 2006 Meltzer 2007 p 118 Hofland Stofel amp Taenaka 1996 p 9 Blagdon 1980 p 83 Meltzer 2007 p 122 NASA NSSDC Experiment Query Results NASA Archived from the original on January 18 2009 Milos 1997 pp 705 713 Galileo Plunges Into Jupiter September 22 2003 Retrieved February 10 2022 Badescu amp Zacny 2018 p 836 Ritter et al 2006 p 6 Space Launch 1989 084 Knihovna Akademie ved CR Retrieved December 3 2018 References editBadescu Viorel Zacny Kris 2018 Outer Solar System Prospective Energy and Material Resources Springer ISBN 978 3 319 73845 1 OCLC 1042249198 Blagdon L 1980 Galileo Lithium SO2 The 1979 Goddard Space Flight Center Battery Workshop PDF Goddard Space Flight Center NASA pp 83 95 Retrieved March 7 2021 Beyer P E O Connor R C Mudgway D J May 15 1992 Galileo Early Cruise Including Venus First Earth and Gaspra Encounters PDF The Telecommunications and Data Acquisition Report 265 281 TDA Progress Report 42 109 Retrieved March 6 2021 Bennett Gary L Hemler Richard J Schock Alfred October 9 14 1994 Development and Use of the Galileo and Ulysses Power Sources 45th Congress of the International Astronautical Federation Jerusalem Israel Retrieved December 7 2020 Dawson Virginia Bowles Mark 2004 Taming Liquid Hydrogen The Centaur Upper Stage Rocket PDF The NASA History Series Washington DC NASA SP 4230 Retrieved October 1 2020 Hofland L M Stofel E J Taenaka R K 1996 Galileo Probe Lithium Sulfur Dioxide Cell Life Testing Proceedings of 11th Annual Battery Conference on Applications and Advances Long Beach California pp 9 14 doi 10 1109 BCAA 1996 484963 Laub B Venkatapathy E October 6 9 2003 Thermal Protection System Technology and Facility Needs for Demanding Future Planetary Missions International Workshop on Planetary Probe Atmospheric Entry and Descent Trajectory Analysis and Science PDF Lisbon Portugal University of Idaho pp 1 9 Archived from the original PDF on January 8 2007 Retrieved December 12 2006 Meltzer Michael 2007 Mission to Jupiter A History of theGalileoProject PDF The NASA History Series Washington DC NASA OCLC 124150579 SP 4231 Retrieved January 19 2021 Milos Frank S 1997 Galileo Probe Heat Shield Ablation Experiment Journal of Spacecraft and Rockets 34 6 705 713 Bibcode 1997JSpRo 34 705M doi 10 2514 2 3293 ISSN 1533 6794 Ritter H Mazoue F Santovincenzo A Atzei A 2006 Jupiter Entry Probe Feasibility Study from the ESTEC CDF Team Heat Flux Evaluation amp TPS Definition Thermal Protection Systems and Hot Structures 631 6 Bibcode 2006ESASP 631E 6R Siddiqi Asif A 2018 Beyond Earth A Chronicle of Deep Space Exploration 1958 2016 PDF The NASA History Series second ed Washington DC NASA History Program Office ISBN 978 1 62683 042 4 LCCN 2017059404 SP 4041 Retrieved October 29 2020 Siewiorek Daniel Swarz Robert S 1998 Reliable Computer Systems Natick Massachusetts A K Peters ISBN 1 56881 092 X OCLC 245700546 Taylor Jim Cheung Kar Ming Seo Dongae July 2002 Galileo Telecommunications PDF DESCANSO Design and Performance Summary Series Washington DC NASA Retrieved November 15 2020 Tomayko James E March 1988 Computers in Spaceflight The NASA Experience PDF Report NASA History Office Retrieved October 29 2020 External links edit nbsp Wikimedia Commons has media related to Galileo mission Galileo mission site by NASA s Solar System Exploration Galileo legacy site by NASA s Solar System Exploration Galileo Satellite Image Mosaics by Arizona State University Galileo image album by Kevin M Gill Early probe results report Galileo Probe NASA Space Science Data Coordinated Archive Portals nbsp Astronomy nbsp Stars nbsp Spaceflight nbsp Outer space nbsp Solar System Retrieved from https en wikipedia org w index php title Galileo spacecraft amp oldid 1220548898, wikipedia, wiki, book, books, library,

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