ROSAT
| ROSAT | |
|---|---|
|
|
| Type: | X-ray satellite |
| Country: | Germany |
| Operator: | DLR |
| COSPAR-ID : | 1990-049A |
| Mission dates | |
| Dimensions: | 2426 kg |
| Size: | 2.20 m × 4.70 m × 8.90 m |
| Begin: | June 1, 1990, 17:48 UTC |
| Starting place: | Cape Canaveral LC-17A |
| Launcher: | Delta II 6920-10 D-195 |
| Flight duration: | 9 years |
| Status: | shut down on February 12, 1999,
Re-entry on October 23, 2011 |
| Orbit data | |
| Rotation time : | 96 min |
| Track height: | 580 km |
| Orbit inclination : | 53 ° |
ROSAT (from X- ray satellite ) was a satellite designed as an X-ray observatory . At 2,426 kilograms it was the heaviest German satellite to date, cost 560 million DM (with US and British participation), was in operation from 1990 to 1999 and was destroyed on October 23, 2011 when it reentered the earth's atmosphere.
Active time
ROSAT was originally supposed to be transported into space and back to earth with a space shuttle . After the crash of the Challenger the schedule was changed in favor of a conventional rocket. ROSAT was brought into orbit with a Delta-II on June 1, 1990 at an altitude of 580 km with an inclination of 53 °, was in operation until February 12, 1999 and significantly exceeded the originally planned mission duration of five years. In addition to a four-fold nested Wolter telescope (his mirrors were long, according to Guinness World Records as the glattesten the world) in the soft and medium-hard X-ray range was ROSAT even with a triple-nested Wolter telescope for the E xtremen U ltra v iolet area ( EUV area ). The instruments included various particle counters, a high-resolution detector for X-ray and UV radiation (High Resolution Imager, HRI) and a wide-angle camera (Wide Field Camera, WFC). The satellite was controlled by the DLR in Oberpfaffenhofen near Munich. The scientific management was at the Max Planck Institute for Extraterrestrial Physics under the direction of Professor Joachim Trümper . ROSAT was built under the system management of Dornier- System GmbH in Friedrichshafen with the participation of national ( Carl Zeiss ), American and British companies.
With ROSAT, the entire sky was scanned in the X-ray range. 125,000 new X-ray sources and 479 EUV sources were discovered. The scientific results are recorded in over 7000 publications worldwide, which have been cited around 100,000 times.
The most important discoveries include the resolution of cosmic X-ray background radiation into the emission of quasars and other active galaxies , the discovery of neutron stars that only radiate thermally, the X-rays from comet Hyakutake 1996 and dozens of new supernova remnants . An X-ray source was also found at the location of the 1987A supernova in the Large Magellanic Cloud . The very successful space observatory also focused on galaxy clusters , X-ray binary stars , pulsars and black holes . ROSATs temporal resolution enabled even the temporal separation of Krebsnebelpulsars (flashing duration 0.033 s). ROSAT also discovered that the moon reflects X-rays from the sun .
In 1998, ROSAT suffered several defects which significantly impaired its usability. On April 25, 1998, the primary star sensor of the X-ray telescope failed; the resulting misalignment resulted in overheating from solar radiation. On September 20, saturation of a twist wheel caused another misalignment, which exposed the HRI directly to the sun and severely damaged it. After the fuel for attitude control was also almost used up, ROSAT was switched off on February 12, 1999. From this point on, the satellite was in a slowly descending orbit.
Re-entry 2011
The calculations by DLR and other agencies had shown that the satellite would not burn up completely when it re-entered the atmosphere due to its large mass and compact components made of heat-resistant materials . Since ROSAT had no engine, there was no way of deliberately causing it to crash.
In the 1980s, when ROSAT was designed and manufactured, no special provisions were usually made for satellites to completely burn up on re-entry. It was only from the end of the 1990s that it was possible to calculate how satellites would break and burn up on reentry, for example with the SCARAB software ( Space Craft Atmospheric Re-entry and Aero-thermal Break up ), which was commissioned by ESA in 1995 . SCARAB also determines the impact area and the resulting risk of damage. In the case of ROSAT, for these calculations the heat resistance of the Zerodur glass ceramic and other materials first had to be determined in the laboratory in order to simulate the behavior of the satellite in the atmosphere.
The time and place of the re-entry into the earth's atmosphere were given by DLR as October 23, 2011, 01:50 UTC (3:50 a.m. CEST) over the Bay of Bengal . From space-track.org the reentry coordinates are 7 ° N , 90 ° O ( Indian Ocean to the west Nicobar Islands ) indicated. The time given here is 01:50 UTC ± 7 min. Confirmed reports about reaching the surface or damage from rubble are not available.
See also
literature
- Joachim Trümper The X-ray satellite Rosat , Physikalische Blätter, Volume 46, 1990, pp. 137-143, doi: 10.1002 / phbl.19900460502
- Trümper The exploration of the sky with the X-ray satellite ROSAT , Physikalische Blätter, Volume 47, 1991, pp. 29–33, doi: 10.1002 / phbl.19910470109
- Trümper ROSAT interim balance - a new image of the sky , Physikalische Blätter, Volume 50, 1994, pp. 35–42, doi: 10.1002 / phbl.19940500111
- Trümper Astrophysik: ROSAT and its successors: The research satellite ROSAT has revolutionized X-ray astronomy , Physikalische Blätter, Volume 55, 1999, pp. 45–49, doi: 10.1002 / phbl.19990550910
- M. Sterzik Rosat and the formation of stars in the Milky Way , Physikalische Blätter, Volume 53, 1997, pp. 539-541, doi: 10.1002 / phbl.19970530612
Web links
Wikinews: ROSAT - in the news- DLR: ROSAT
- DLR: The re-entry
- Max Planck Institute for Extraterrestrial Physics: The ROSAT mission (English)
- Max Planck Institute for Extraterrestrial Physics: The ROSAT all-sky survey (English)
- Raumzeit-Podcast 23 and 24: ROSAT ROSAT re-entry
Individual evidence
- ↑ ROSAT / LEDAS electronic newsletter. (No longer available online.) UK ROSAT Guest Observer Center, June 5, 1998, archived from the original on December 28, 2015 ; accessed on February 26, 2011 (English, No. 12). Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- ^ The Last Days of ROSAT. Max Planck Institute for Extraterrestrial Physics, accessed on June 12, 2010 (English): "ROSAT turned off on Feb-12, 1999 at 09:18:52 UT"
- ↑ Rosat's official homepage. Retrieved August 10, 2011 .
- ↑ ratchet wheel, Alby, Alwes, Portelli, Tremayne-Smith: Space Debris Activities in Europe . In: Proceedings of the Fourth European Conference on Space Debris . April 2005, p. 5 , bibcode : 2005ESASP.587 ... 25K (English).
- ^ Koppenwallner, Fritsche, Lips: Multidisciplinary Analysis Tools for Orbit and Re-entry. (PDF; 1.2 MB) October 2006, pp. 15–34 , accessed on October 13, 2011 (English).
- ↑ G. Koppenwallner: HTG and main areas of work in space technology. (PDF; 2.3 MB) 2003, pp. 14.26 , accessed on October 12, 2011 .
- ↑ ROSAT entered the Earth's atmosphere via the Bay of Bengal , DLR press release, October 25, 2011 at 10:51:23 am
