July 23, 1999: Chandra X-Ray Observatory Launched

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  Space News Business

July 23, 1999: Chandra X-Ray Observatory Launched

By CLINTON PARKS
Space News Staff Writer
posted: 31 July 2007
03:54 pm ET





Washington



Since its launch eight years ago, the




Chandra X-Ray Observatory has provided




star-gazing scientists with detailed images of high-energy phenomena across the




universe such as




black holes and supernovas.



Chandra l




aunched aboard the




Space Shuttle Columbia




July 23, 1999.
The spacecraft




was named for Subrahmanyan Chandrasekhar, one of the first scientists to combine the fields of astronomy and




physics




. The Indian-American Nobel laureate studied the structure and evolution of the universe, and is known best for his work with white dwarfs and neutron stars.

Originally scheduled for launch




July 20, the




launch was scrubbed several times because of sensor problems and lightning storms.

Several system failures occurred both on the




pad and during the shuttle launch




. Five seconds after the shuttle launched, backup engine controllers took over when a short circuit disabled two of the three main engine controllers




. During ascent, additional liquid oxygen propellant was used to compensate for a




hydrogen leak in the third engine




, which almost caused it to redline.





After it was released from the shuttle’s cargo bay, Chandra’s




inertial upper stage also




underperformed, leaving it about 900




kilometers short of its planned highly




elliptical orbit;




it had to use its own engines to reach its destination, which was




a third of the way to the Moon.





Despite




those early obstacles,




the telescope




transmitted its first images in August




1999, and has lasted beyond its projected five-year service life




. It averages




1,000 observations a year.

Some of




Chandra’s most notable findings include revealing




distant galaxies




10 billion light years away,




proving dark energy makes up 70 percent of the universe and confirming the Hubble Constant, the measure of the rate of expansion of the universe.







Chandra was capable of delivering images with resolutions 25 times greater




than its predecessors








due to its four pairs of precisely made near-cylindrical mirrors, which were




flattened to within a few atoms of levelness.





Built by TRW Space and Electronics of Redondo Beach, Calif. – now Northrop Grumman Space Technology –




for $1.5 billion,




Chandra




is one of NASA’s “Great Observatories”




along with the Hubble Space Telescope, Spitzer Space Telescope and the now-de




orbited
Compton Gamma Ray Observatory.





Chandra’s mission is managed at the Harvard-Smithsonian Astrophysical Observatory in Cambridge, Mass., with three ground stations




in California, Spain and Australia.




Mission participants include the United Kingdom, the Netherlands and Germany.