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AXAF-I (Chandra, CXO)

AXAF-I (Chandra) [NASA]

AXAF-I (Advanced X-Ray Astronomy Facility - Imager), renamed CXO (Chandra X-Ray Observatory), was built around a high-resolution grazing incidence X-ray telescope which will make astrophysical observations in the 0.09 to 10.0 keV energy range.

The principal science objectives of the mission were to determine the nature of celestial objects from normal stars to quasars, to understand the nature of physical processes which take place in and between astronomical objects, and to generally study the history and evolution of the universe. Observations will be made of X-rays from high energy regions such as supernova remnants, X-ray pulsars, black holes, neutron stars, and hot galactic clusters.

The spacecraft has a cone-shaped body with an octagonal structure surrounding the wide end. Two solar panel wings extend from opposite sides of the structure. The main opening is at the wide end covered by a sunshade door with a contamination cover. An aspect camera and stray light shade are mounted near the opening and 2 low gain antennas and two fine Sun sensors are affixed to the outside structure. Thermal control is maintained by a radiator, insulators, heaters, and thermostats. Power generated by the solar panels is stored in three banks of batteries. The 10 m focal length X-ray telescope consists of four nested paraboloid-hyperboloid X-ray mirror pairs, arranged in concentric cylinders within the cone.

The four instruments are located near the focus at the narrow end of the cone:

  • High Resolution Camera (HRC)
  • AXAF CCD Imaging Spectrometer (ACIS)
  • High-Energy Transmission Grating (HETG), nonfocal
  • Low-Energy Transmission Grating (LETG), nonfocal

The originally planned XRS X-ray microcalorimeter detector was spun off to a separate mission, AXAF-S, to be launched by a Delta rocket into a polar sunsynchronous orbit. This in turn was later cancelled and the XRS was launched on the Japanese ASTRO-E mission.

Nation: USA
Type / Application: Astronomy, X-Ray
Operator: NASA
Contractors: TRW
Equipment: X-ray telescope (10 m focal length), HRC, ACIS, HETG, LETG
Propulsion: 4 × TR-308 thrusters (472 N)
Power: 2 deployable solar arrays, batteries
Lifetime: 10 years (design)
Mass: 5200 kg
Orbit: 9942 km × 140000 km, 28.5
Satellite COSPAR Date LS Launch Vehicle Remarks
AXAF-I (CXO, Chandra) 1999-040B 23.07.1999 CCK LC-39B Shuttle [IUS] with Columbia F26 (STS 93)


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