F R 1 - 9 7

Home | Update | Latest Issue | Gallery | FR Profile | Datafiles | FR 1/97 ORFEUS LOOKS AT "WHITE DWARFS" by Wolfgang Engelhardt On November 19, 1996, the US Space Shuttle Columbia lifted-off for the 80th Shuttle mission. Its payload bay contained the American "Wake Shield Facility" for material experiments in a total vacuum and the German Astro-Spas satellite with the Orfeus telescope for astronomic research in ultraviolet light. Only eight hours after the launch the Spas satellite was lifted out of Columbia's payload bay and released. It was the third sortie of this orbital platform which was built by Dornier Satellitensysteme GmbH, a Dasa company. For the second time, the satellite was equipped with the Orfeus telescope, built by Kayser-Threde. The instrument measures one meter in diameter and has a focal length of 2,4 meters. Orfeus registers data in the spectral range of 40 to 125 Nanometers, which is far in the ultraviolet range. The system allows a very good evaluation of very hot suns which are at the end of their life-cycle (so called "white dwarfs"). The spectrometer in the focal point of the Orfeus telescope splits off the radiation with the highest possible resolution into its spectral contents, allowing the astronauts to evaluate specifics of the chemical and physical condition of a sun or of a galaxy. With the recent employment of the Orfeus-Spas satellite, the measurements were being continued which were started during the telescope's first flight with Shuttle mission STS-51 at the end of 1993. The autonomous operation of the telescope satellite is controlled from the mobile control station SPOC which Dornier has specifically set up in Florida. The Orfeus-Spas satellite operated for two weeks in its orbit and was then recovered by Columbia. Between those two Orfeus missions, the Spas satellite was used during Shuttle flight STS-66 at the end of 1994, carrying the deep-frozen infrared telescope Crista which recorded the contents of the earth's atmosphere and the endangered ozone layer with high accuracy. The idea of a reusable Shuttle pallet satellite, which can be employed with different payloads, was already developed by Messerschmitt Bölkow Blohm (MBB) in 1978 and NASA choose to use this concept already during six missions with various payloads. Today's Astro-Spas research program was developed by the German Space Agency (DARA) with two different payloads, each of which was designated for at least two missions. The recent Shuttle mission with the Orfeus-Spas satellite was also of much interest for many German pupils. They participated in a country-wide initiative "schools in the net", which was started by DARA and the Research Ministry, allowing them to monitor the measurements of the Orfeus telescope live via Internet in their classrooms. From page 38 of FLUG REVUE 1/97 Home | Update | Latest Issue | Gallery | FR Profile | Datafiles | FR 1/97 Copyright 1996 by Motor-Presse Stuttgart. All rights reserved. Last updated December 11, 1996