Chandra X-Ray Observatory

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Chandra X-Ray Observatory

An orbiting X-ray astronomy observatory launched by NASA in July 1999 as the third of its Great Observatories. Chandra, which takes its name from the 20th-century Indian-born US astrophysicist Subrahmanyan Chandrasekhar, was originally developed as one of the craft making up NASA's Advanced X-Ray Astrophysics Facility (see AXAF); dubbed AXAF-I and renamed after its launch, Chandra was equipped for high-resolution X-ray imaging and was deployed by the space shuttle Columbia into a highly eccentric orbit (apogee 140 161 km, inclination 28.5°) that has allowed long periods of observation unimpeded by Earth shadowing. Chandra's optics consist of four nested pairs of grazing incidence paraboloid and hyperboloid mirrors, each having an outer diameter of 1.2 meters and a focal length of 10 meters. With its Advanced Charged Couple Imaging Spectrometer (ACIS) and its high-resolution camera using large field-of-view microchannel plates to make X-ray images, Chandra's optical system achieves an angular resolution of 0.5 arcseconds over an operating range of 0.2–10 keV. Its high- and low-energy transmission gratings provide impressive spectral resolution throughout the range 0.09–10 keV.

Chandra has been called the most sophisticated X-ray observatory of its time, providing images of unprecedented detail at resolutions that are claimed to be about 50 times better than those achieved by ROSAT, the best X-ray astronomy satellite prior to 1999. In its first five years, Chandra has begun to penetrate the hottest, most energetic regions of the Universe. In particular, it has advanced our knowledge of black holes, discovering among many other things how fast they spin, finding evidence of a star torn apart by a black hole, and emphatically confirming the reality of the event horizon. It has revealed enormous tracts of hot gas, billions of parsecs distant and radiating at temperatures of tens of millions of degrees K. It has provided startling new images of supernova remnants such as the Crab Nebula, with its restless pulsar, showing intricate details never suspected before. It has made new studies of star-forming regions such as the Orion Nebula and analyzed the effects of galaxy collisions and the merging of galaxy clusters. Most notably, it has gathered direct evidence of dark energy and the expansion of the Universe.

References in periodicals archive ?
Month Event January Lunar Prospector March Transition Region and Coronal Explorer July Deep Space 1 Sattelite de Aplicaciones Cientificas-A August Topographic Experiment using Radiative Recombinative Ionospheric EUV and Radio Sources Planet B September Wide-Field Infrared Explorer October Far Ultraviolet Spectroscopic Explorer Flight test of a cryogenic cooler for the Hubble Space Telescope's infrared camera November Advanced X-ray Astrophysics Facility December Mars 98 Orbiter
The only new scientific satellite proposed for NASA's budget is the Advanced X-Ray Astrophysics Facility, to be placed in earth-orbit by the shuttle by 1996.
Next year, NASA will launch the Advanced X-ray Astrophysics Facility (AXAF), the last of three space telescopes.
Another light may be available, he says, when the Advanced X-Ray Astrophysics Facility (still awaiting federal funding) is put into service to observe the X-ray halos thought to encircle many elliptical galaxies.
This award also extends TRW's legacy of building mission-enabling spacecraft for NASA's challenging space science missions, including the Compton Gamma Ray Observatory, launched in 1991, and the Advanced X-ray Astrophysics Facility (AXAF), scheduled for launch in early 1999," added Maguire.
This is 1,000 times that of AXAF, the Advanced X-ray Astrophysics Facility that NASA intends to put into orbit early in the next decade.
BUSINESS WIRE)--May 7, 1997--NASA's Advanced X-ray Astrophysics Facility (AXAF) program has reached a major milestone with the delivery of the space observatory's central optical component to TRW (NYSE: TRW), the AXAF prime contractor.

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