The IUE Spacecraft

Mass: 644 kg at launch, 462 kg in orbit

Dimensions: 4.2 m by 1.45 m by 1.45 m

Power: 2 solar panels, which provide operating power to the spacecraft, and 2 batteries, which provide power during biannual Earth shadow seasons

Slewing: 3 reaction wheels (1 backup, never used)

Attitude sensors: 2 gyros (out of original 6), 1 Fine Sun Sensor (1 backup)

Computers: 1 8k on-board computer (1 backup, never used)

Orbit: synchronous, with semi-major axis 42167 km, inclination 34.7 deg, and eccentricity 0.132 (as of mid-1994)

Telemetry: uplink at 148.98 MHz (VHF) at 0.8 kbits/sec; S-band downlink at 2249.80 MHz at rates from 1.25 to 20 kbits/sec (standard), or VHF downlink at 136.86 MHz at rates from 1.25 to 5 kbits/sec

Ground stations: NASA IUE Observatory at Goddard Space Flight Center, Greenbelt, MD, USA (via Wallops Island Flight Facility, VA, USA), and ESA IUE Observatory at Villefranca del Castillo, Madrid, Spain

Command method: Real-time commanding by on-station personnel under advice from peer-selected guest observers; no coordination with TDRSS or other ground communication systems needed

More information?

Please see the article "Operation of a Multi-Year, Multi-Agency Project" describing the IUE mission (Falker, J., Gordon, F., Sanford, M.C.W., 1987, Exploring the Universe with the IUE Satellite , Reidel (and appears here with permission of Kluwer Academic Publishers): Dordrecht, ed. Y. Kondo, pg. 21).

Also, the IUE Observing Guide gives a description of the spacecraft, instrument, observing constraints, and so forth. (Important updates and details on the instrumental status were added by J. Caplinger in 1994.)