Friday, July 23, 1999 Published at 16:56 GMT 17:56 UK
Shuttle deploys X-ray observatory
Chandra eases away from the shuttle
By BBC News Online Science Editor Dr David Whitehouse
The astronauts, led by Nasa's first woman space shuttle commander, Eileen Collins, released Chandra with the flick of a switch seven hours and 16 minutes after launch.
Later the rocket motor on Chandra fired to take it into its high, 25-hour orbit.
Chandra will then begin an extensive checkout and calibration procedure. It will be another month before the telescope's eagerly awaited observations begin.
The Chandra X-ray Observatory will spend at least five years observing X-rays from the hottest and most violent parts of the cosmos, looking in particular at superheated matter being pulled into black holes.
Chandra should herald a revolution in X-ray astronomy. It is 10 to 100 times more powerful than any of the dozen or so X-ray telescopes previously placed in orbit.
Matter being sucked into a black hole can be heated to millions of degrees as it swirls in a so-called "accretion disc" around the black hole.
It is the third of Nasa's four "Great Observatories". The first was Hubble and the second was the Compton Gamma Ray Observatory, launched in 1991.