Hélios 1A and Hélios 1B were French military photo-reconnaissance satellites in which Italy and Spain also participated. Hélios 1A was launched from the Guiana Space Centre, French Guiana on 3 December 1999 at 16:22:00 UTC. The spacecraft rode aboard an Ariane 4 rocket which also carried the French military reconnaissance satellite Clementine.
The two Helios 1 satellites constitute the first generation of the program, the development of which was launched in 1985.[1] They ooperated in a Sun-synchronous orbit at an altitude of 678 km. Their instruments offered a resolution of the order of one or two meters on the ground.
Derived from SPOT 4, they retained the platform but were equipped with an attitude and orbit control system (SCAO). This system realized the kinematics of the orientation of the satellite via flywheels. This system allowed fine pointing of the shooting lens for several seconds, thus increasing the quality of the images. The SPOT 4 mirror was also replaced, making it possible to target targets outside the satellite's trajectory. The control of the orientation kinematics is ensured by the SCAO via the stellar sensors. Three in number, these are the three cones that we see protruding from the platform. Only two are active at the same time. The flywheels are then controlled by the SCAO which tries to follow a selection of the brightest stars in order to ensure the desired kinematics. This selection of stars is programmed by the ground mission software.
Helios 1A and 1B are distinguished from SPOT 4 by the absence of polychromy of the images (they are in black and white) optimizing the image storage capacity.
Helios 1A was launched on July 7, 1995 by an Ariane 4 launcher. Due to power supply failures, it had to be left to disintegrate in 2005. Helios 1B was launched on December 3, 1999.[2] Helios 1B was voluntarily de-orbited in October 2004 before definitively losing control. The satellite has been the victim of a loss of charge of an accumulator since May of the same year which in turn leads to the premature wear of the others. Helios 1A ceased to be operational in February 2012 and was also purposely de-orbited.[3]
It has been replaced by Hélios 2A, launched in December 2004 on an Ariane 5 rocket.[4]
Bibliographyedit
(in French and English) Guy Lebègue, (trad. Robert J. Amral), « Helios: The Orbiting Spyglass », in Revue aerospatiale, n°118, May 1995.
Referencesedit
^"History of the French reconnaissance system". SatelliteObservation.net. 6 November 2016. Retrieved December 6, 2022.
^"Ariane launches Helios 1B". Flight International. 14 December 1999. Retrieved December 6, 2022.
^Krebs, Gunter D. "Helios 1A, 1B". Gunter's Space Page. Retrieved December 31, 2022.
^Cain, Fraser (December 20, 2004). "Ariane Lofts 7 Satellites at Once". Universe Today. Retrieved December 30, 2022.
hélios, other, spacecraft, named, helios, helios, disambiguation, space, this, article, needs, additional, citations, verification, please, help, improve, this, article, adding, citations, reliable, sources, unsourced, material, challenged, removed, find, sour. For other spacecraft named Helios see Helios disambiguation Space This article needs additional citations for verification Please help improve this article by adding citations to reliable sources Unsourced material may be challenged and removed Find sources Helios 1B news newspapers books scholar JSTOR December 2022 Learn how and when to remove this template message Helios 1A and Helios 1B were French military photo reconnaissance satellites in which Italy and Spain also participated Helios 1A was launched from the Guiana Space Centre French Guiana on 3 December 1999 at 16 22 00 UTC The spacecraft rode aboard an Ariane 4 rocket which also carried the French military reconnaissance satellite Clementine Helios 1 Contents 1 Mission 2 Bibliography 3 References 4 External linksMission editThe two Helios 1 satellites constitute the first generation of the program the development of which was launched in 1985 1 They ooperated in a Sun synchronous orbit at an altitude of 678 km Their instruments offered a resolution of the order of one or two meters on the ground Derived from SPOT 4 they retained the platform but were equipped with an attitude and orbit control system SCAO This system realized the kinematics of the orientation of the satellite via flywheels This system allowed fine pointing of the shooting lens for several seconds thus increasing the quality of the images The SPOT 4 mirror was also replaced making it possible to target targets outside the satellite s trajectory The control of the orientation kinematics is ensured by the SCAO via the stellar sensors Three in number these are the three cones that we see protruding from the platform Only two are active at the same time The flywheels are then controlled by the SCAO which tries to follow a selection of the brightest stars in order to ensure the desired kinematics This selection of stars is programmed by the ground mission software Helios 1A and 1B are distinguished from SPOT 4 by the absence of polychromy of the images they are in black and white optimizing the image storage capacity Helios 1A was launched on July 7 1995 by an Ariane 4 launcher Due to power supply failures it had to be left to disintegrate in 2005 Helios 1B was launched on December 3 1999 2 Helios 1B was voluntarily de orbited in October 2004 before definitively losing control The satellite has been the victim of a loss of charge of an accumulator since May of the same year which in turn leads to the premature wear of the others Helios 1A ceased to be operational in February 2012 and was also purposely de orbited 3 It has been replaced by Helios 2A launched in December 2004 on an Ariane 5 rocket 4 Bibliography edit in French and English Guy Lebegue trad Robert J Amral Helios The Orbiting Spyglass in Revue aerospatiale n 118 May 1995 References edit History of the French reconnaissance system SatelliteObservation net 6 November 2016 Retrieved December 6 2022 Ariane launches Helios 1B Flight International 14 December 1999 Retrieved December 6 2022 Krebs Gunter D Helios 1A 1B Gunter s Space Page Retrieved December 31 2022 Cain Fraser December 20 2004 Ariane Lofts 7 Satellites at Once Universe Today Retrieved December 30 2022 External links edit nbsp Spaceflight portalNASA Helios 1B nbsp This article about one or more spacecraft of France is a stub You can help Wikipedia by expanding it vte Retrieved from https en wikipedia org w index php title Helios 1B amp oldid 1176563732, wikipedia, wiki, book, books, library,
