Spacecraft Configuration

The ROSAT configuration is characterized by two main features. One is the size of the X-ray telescope (XRT), and the design for a Delta II launch the other.

The XRT is enclosed by the square shaped central central body in which that part which serves as optical bench between mirror assenbly and focal plane instrumentation. The isostatic mounting via three bearings decouples the telescope from thermal/mechanical distortions of the satellite structure.

At the front end the telescope carries the two star trackers and the gyro package, the most important units for attitude measurement, thus experiencing the same deformations as the telescope and allowing to meet the stringent accuracy requirements. The XRT door serves as sunshade during the mission. On ground is also protects both the telescope and the star trackers against contamination. The XRT can be dismounted entirely after removal of the rear central body panel, which also supports the wide field camera (WFC).

Two compartments on both sides of the central body house almost all subsystem units. This allows good accessibility and a simple and independent integration.

At the rear part of the central body the Delta II adaption cone is attached which provides the interface to the second stage of the Delta II launch vehicle.

The area of the solar generator totals to about 12 m², distributed on one fixed central panel anf two hinged deployable panels.

The largely free rear surface allows the dissipation of excess heat into space and consequently limits the temperature to reasonable levels. A deployable boom carries the S-band antenna and the magnetometer.

For transportation the satellite can be disassembled into the central body, including the XRT andsolar panels stowed and into the WFC. Thus in spite of the size the spacecraft still fits into conventional transportation means.

A summary of ROSAT system parameters is given in the following table:

Major System Parameter
dimension (launch configuraion) 2,38 × 2,13 × 4,50 m³
total mass 2426 kg
payload mass 1555 kg
power consumption
- sun phase
- eclipse

905 W
337 W
available power 1.000 W
data rate 700 Mbit pro 21 h

ROSAT (Röntgensatellit)
Copyright © 1998 Max-Planck-Institut für extraterrestrische Physik, 85740 Garching, Germany.
The ROSAT project is run by the German Aerospace Center (DLR) (former DARA), Bonn, by order of the Bundesministerium für Bildung, Wissenschaft, Forschung und Technologie (BMBF). All rights reserved.