EXOSAT | Article about EXOSAT by The Free Dictionary
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EXOSAT (eks -oh-sat) The first European Space Agency mission in X-ray astronomy, a sophisticated 400-kg satellite launched in May 1983 carrying a payload of two grazing incidence telescopes, a large (1800 cm2) array of proportional counters, and a (90 cm2) gas scintillation proportional counter. The unusual orbit of EXOSAT, initially 380 km perigee, 195 000 km apogee, gave it the unique capability of long (˜80 hr) observations, uninterrupted by Earth occultation. With apogee over N Europe, direct contact with the ground station at Villafranca (Madrid) furthermore allowed EXOSAT to be operated directly by the astronomer, much like a ground-based telescope. Although problems occurred with two detectors early in the mission, rendering one telescope inoperable, the spacecraft systems, including on-board computer and 3-axis attitude control system, worked well until exhaustion of attitude control gas in Mar. 1986. Outstanding results were obtained on a wide range of supernova remnants, X-ray binaries, X-ray burst sources, active galaxies, and clusters of galaxies. The discovery of quasi-periodic oscillations (QPOs) uncovered an important property of accreting binary systems not known before EXOSAT. See also EXOSAT Database.
References in periodicals archive
White of the European Space Agency (ESA) found the orbiting system in data taken by ESA's orbiting X-ray observatory, Exosat
. "We know of no other double star system with stars this close," says Priedhorsky.
This time, an-ray survey of the center of the galaxy using the satellite Exosat
has found a mysterious "ridge" of X-ray emissions stretching for 40[deg.' on each side of the galactic center, two ninths of the way around the sky.
The observers used the European Space Agency's EXOSAT