ROSAT

 1990-049A

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The ROSAT (Rontgensatellit) X-ray observatory, launched in Jun 1990, was similar to NASA's Einstein observatory but with improved spatial and spectral resolution. It carried nested X-ray mirrors which focused radiation onto a PSPC (Position Sensitive Proportional Counter, similar to the Einstein IPC) and an HRI (High Resolution Imager, supplied by the US team that built the similar instrument on Einstein). A separate but coaligned extreme ultraviolet telescope, the Wide Field Camera (WFC), was built by the UK Leicester University group. The mission was operated by MPE in Germany in collaboration with NASA and the UK. The first six months of the mission saw an all sky survey by the PSPC instrument. At the end of the survey, a power failure caused the spacecraft to lose attitude control and accidentally point at the Sun, which severely damaged the PSPC-C instrument then in the focal plane and degraded the WFC. Fortunately a backup PSPC and the HRI were available to support continued operations in the pointed phase, which was opened to astronomers across the world.

ROSAT
Date	Time	Event	Orbit
1990 Jun 1	2147:59	Launch by Delta 6920	CC LC17A
		T+0:55 SRM 1-6 burnout
		T+1:00 SRM 7-9 burn
		T+1:02 SRM 1-6 sep
		T+1:56 SRM 7-9 burnout
	2149:56	T+2:02 Final 3 Castor sep
	2152:25	T+4:24 Thor cutoff
	2152:30	T+4:32 Thor sep
		T+4:38 Delta burn
	2152	T+4:43 Fairing sep
	2159:07	T+11:09 SECO-1 299 km	200? x 580? x 53
	2226:00	T+38:02 Delta circ burn, 12s
	2226:12	T+38:14 SECO-2
	2231	T+43:00 Delta sep	577 x 584 x 53.0
	2226	T+1:39:10 SES-3 evasive
		T+1:39:15 SECO-3
	2237	T+1:50:10 SES-4 depletion
		T+1:50:31 SECO-4	454 x 557 x 52.51
1991 Jan 25		Power failure
1991 Feb 10		Pointed phase
1991 May 13		Y axis gyro failed
1991 Aug 3		Sky survey completion patch
1991 Aug 13		Completed sky survey
1994 Jul		PSPC-B retired
1998 Apr 28		Star tracker failed
1998 Sep 20		Pointed at sun, HRI damaged
1998 Oct 28		end of ops
1998 Dec 6		PSPC observations
1998 Dec 18		PSPC observations ended
1999 Feb 12		Decommissioned
2011 Oct 23	0150?	Reentered over Andaman Sea/China?

Payload:

• XRT 0.84m aperture Wolter I X-ray Telescope Zerodur/Au, 4 shells, f=2.4m

• WFC 0.58m aperture XUV Wide Field Camera, Ni-Al/Au mirrors f=0.52m 0.04-0.2 keV (60-300A)

• PSPC-C Position Sensitive Proportional Counter, 0.1-2.4 keV

• PSPC-B Position Sensitive Proportional Counter.

• HRI High Resolution Imager (SAO/Murray)