BBC News' Pallab Ghosh reports on the historic launch and the mission

Space Shuttle Columbia has deployed the Chandra X-ray observatory, one of the most powerful space observatories ever put into orbit.

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.

The shuttle took off at the third attempt

Columbia then fired its manoeuvring thrusters for four seconds to move away from Chandra.

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.

X-ray revolution

Nasa commentary of Chandra deployment

It weighs over 25 tonnes and is the largest payload ever carried by the space shuttle. Columbia had to be specially modified for the mission.

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.

Columbia had to be modified to carry Chandra

X-rays in space are produced by the superheating of gas. Chandra will observe the violent cores of distant galaxies called quasars where it is believed that matter is being dragged into super massive black holes. It will also watch the remnants of exploded stars by tracing the dispersal of hot gas.

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.

Eileen Collins explains how Chandra works

The telescope is named after the late Nobel prize-winning astronomer Subrahmanyan Chandrasekhar and cost $1.5 billion.