1999-040B
The Advanced X-Ray Astrophysics Facility (AXAF) is a NASA Great Observatory. The AXAF mission was split in the early 1990s into AXAF-I (Imaging) and AXAF-S (Spectroscopic), but AXAF-S was later cancelled. The 5563 kg Chandra (AXAF) (formerly AXAF-I) spacecraft is a 10-meter focal length subarcsecond resolution X-ray telescope with both imaging and spectroscopic capability. It is 14.0 m long and 19.5m span across the solar arrays. Prime contractor was TRW/Redondo Beach; lead center was NASA-MSFC with operations and science center at the joint SAO/MIT AXAF Science Center in Cambridge, Massachusetts.
The spacecraft consists of the Spacecraft module, containing the Integral Propulsion System, the solar panels, and the aperture door; the HRMA; the optical bench; and the ISIM, Integrated Science Instrument Module with the science instruments.
The IPS uses MON-3 (0.97 N2O4 and 0.03 NO) oxidizer and N2H4 (hydrazine) for its bipropellant main thrusters. The RCS thrusters in the IPS use monopropellant N2H4. There is also a monopropellant hydrazine MUPS momentum unloading propulsion system which is used to unload momentum from the attitude control gyroscopes and uses 1N thrusters.
After deployment from the STS, the IUS burns at MET 9:42, and the SRM-2 burns at 9:46, placing AXAF in a 241 x 59923 km orbit. The solar panels are deployed. The IPS-1 burn is at MET 28:55 and raises to 241 x 140000 km; the IPS-2 burn is at MET 58:11 and raises orbit to 10000 x 140000 km. The IPS has 4 TR-308 ACLAE (Advanced Columbium Liquid Apogee Engine) liquid engines derived from TRW's TR-306 DM-LAE. The RCS are 89N monoprop hydrazine.
Launch mass is 5563 kg. After IPS-1, it's 5471 kg; after IPS-2, 5271 kg; after IPS-3, 4888 kg; after IPS-4, 4685 kg; after IPS-5, 4653 kg.
The IPS-4 burn was scrubbed because of performance concerns about LAE-3; the burn was replanned for LAE-2/LAE-4.
Mass at deploy: 19427 kg, post IUS1 10527, pre IUS2 9363, post IUS2 6642
| AXAF | |||
| Date | Time | Event | Orbit |
|---|---|---|---|
| 1970 | HEAO LOXT (1.2m) telescope proposal | ||
| 1973 | HEAO descoped | ||
| 1976 | SAO 1.2m telescope proposal | ||
| 1977 | MSFC/SAO phase A study | ||
| 1980 | AXAF SWG report projects start in FY83 | ||
| 1982 | Field committee makes AXAF top priority | ||
| 1985 | Phase B studies | ||
| 1985 | TMA test mirror | ||
| 1988 | AXAF new start, TRW prime | ||
| 1991 | AXAF science center at SAP | ||
| 1991 | Early tests of outer mirror pair | ||
| 1992 | Descoped to AXAF-I and AXAF-S | ||
| 1994 | AXAF-S cancelled | ||
| 1995 Jul | Grinding and polishing completed at HDOS | ||
| 1996 Feb | Mirrors coated at Santa Rosa | ||
| 1996 Feb | Mirrors to Kodak, assembly | ||
| 1997 Dec | XRCF HRMA tests begin | ||
| 1997 Mar | SC structure complete | ||
| 1997 May | XRCF instrument tests complete | ||
| 1997 Jun | Ship HRMA to TRW | ||
| 1997 Oct | SIM due at TRW | ||
| 1997 Nov | Delivery delay announced | ||
| 1998 Feb | ETE-1 | ||
| 1998 Mar 12 | SA install, assembly complete | ||
| 1999 Feb 4 | Chandra delivery to KSC | ||
| 1999 Mar 8 | CTU and IU reinstalled | ||
| 1999 Mar 23s | Solar array install | ||
| 1999 Apr 5s | Hydr/N2O4 fuelling | ||
| 1999 Jun 3 | Mate to IUS-27 | ||
| 1999 Jun 24 | Transfer to LC39B | ||
| 1999 Jun 27 | Install in OV-102 | ||
| 1999 Jul 20 | 0426 | Attempt 1, scrub T-7 for leak | |
| 1999 Jul 22 | 0428 | Attempt 2, wx | |
| 1999 Jul 23 | 0431:00.04 | Launch by Shuttle | KSC LC39B |
| 0439:33 | MECO | ||
| 0514:25 | OMS-2 | ||
| 0615 | Power up | ||
| 1147:26 | Chandra deploy from OV-102 | 90.10 268 x 290 x 28.5 | |
| 1244:30 | LGA 1 deploy failed | ||
| 1247:26 | D+1:00 IUS burn 1, 125s | ||
| 1247:25 | LGA-1 deployed | ||
| 1249:31 | IUS SRM-1 cutoff | ||
| 1251 | IUS SRM-1 sep | 257.63 226 x 13841 x 28.5 | |
| 1999 Jul 23 | 1251:53 | IUS burn 2 | 1456.26 330 x 72030 x 28.5 |
| 1253:44 | SRM-2 cutoff | ||
| 1322 | Solar array deploy | ||
| 1348:55 | SRM-2 sep (CXO mass 5563 kg) | 1487.26 315 x 73240 x 28.5 | |
| 1999 Jul 25 | 0111:27 | IPS-1 (LAE-1/3) 5:00 | |
| 0116:27 | IPS-1 end | 1481.41 1179 x 72158 x 28.4 | |
| 1999 Jul 26 | 0147:44 | IPS-2 (LAE-1/3) 11:13 | |
| 0158:57 | IPS-2 cutoff (CXO mass 5470 kg ) | 1537.59 3505 x 71995 x 28.5 | |
| 1999 Jul 29 | 3449 x 72052 x 28.5 (OCC) | ||
| 1999 Jul 31 | 2232:50 | IPS-3 (LAE-1/3) (21:31) | |
| 2254:21 | IPS-3 cutoff | 3591.10 3479 x 139125 x 28.5 | |
| 1999 Aug 1 | 3480 x 139124 x 28.5 (DSN) | ||
| 1999 Aug 4 | 1634:08 | IPS-4 (5:00) (LAE-2/4) | 5657 x 139141 x 28.5 |
| 1639:08 | IPS-4 cutoff | 3557.44 5657 x 139141 x 28.5 | |
| 1999 Aug 7 | 0538:31 | IPS-5 (7:44) (LAE-2/4) | |
| 0546:15 | IPS-5 complete | 3807.66 9856 x 138932 x 28.5 | |
| 1999 Aug 8 | 2243 | ACIS Door open | |
| 1999 Aug 13 | Aft contam cover open | ||
| 1999 Aug 13 | 1600 | SSD open | |
| 1999 Aug 13 | First image | ||
| 1999 Aug 17 | 2017 | Safemode | |
| 1999 Nov 25 | 3808.5 10157 x 138663 x 28.8 | ||
| 2010 Aug 31 | 3809.3 7600 x 141235 x 67.5 | ||
Payload:
- HRMA High Res Mirror Assembly, 4 nested Wolter I
- HRC High Resolution Camera (Murray)
- ACIS AXAF CCD Imaging Spectrometer (Garmire)
- LETGS Low Energy Transmission Grating Spec (Brinkman)
- HETGS High Energy Transmission Grating Spec (Canizares)
- ACA Aspect Camera Assembly
- IPS Integral Propulsion System
