EXPLORE


JOINRENEWJOIN

Give a gift membership.
  

Space Topics

Chandra X-Ray Observatory

Chandra X-Ray Observatory

Since its launch in 1999, the Chandra X-ray Observatory, the largest satellite ever and the most sophisticated X-ray telescope in existence, has been providing scientists with unmatched X-ray imagery of deep and exotic parts of the universe.

Named after the Indian-American physicist Subrahmanyan Chandrasekhar, Chandra was launched by NASA on the space shuttle Columbia on July 23, 1999. With its successful launch, it became the third of NASA's four "Great Observatories," a group of space-based telescopes that also includes the Hubble Space Telescope, the Compton Gamma Ray Observatory, and the Spitzer Space Telescope. Chandra was launched into an unusually long elliptical Earth orbit that goes as far as 133,000 kilometers (82,646 miles) away before returning to a minimum altitude of only 16,000 kilometers (9,942 miles) over 64 hours and 18 minutes. The long orbit enables continuous observation periods as long as 55 hours without interference from the spacecraft's passage through the Van Allen belt of charged particles that encircles Earth.

Chandra's mission is to observe X-rays from high-energy areas of the universe, such as nebulae and supernovae with both cameras and high-resolution spectrometers. Chandra was the first telescope to measure the X-rays coming from a supernova shock wave and made the first association between X-ray emission lines and a gamma ray burst. Although not originally intended for planetary exploration, it has been turned to a host of solar system bodies. It has studied X-ray fluorescence in the atmospheres of Venus, Earth, Mars, and Jupiter; studied the comae of comets; found unusual X-ray emissions near Saturn's equator; and explored the composition of the lunar surface.