The Chandra Satellite

Beverly Berger, Oakland University

Those of you who knew Chandra and those who only knew of him will be pleased to learn that NASA has named its soon-to-be-launched Advanced X-ray Astrophysics Facility (formerly AXAF) the Chandra X-ray Observatory. The Chandra Observatory will join the Hubble Space Telescope and the Compton Gamma-ray Observatory in NASA's program of major space-based astronomical facilities. The final observatory in the series, for infrared astronomy (SIRTF), is under development.

The X-ray telescope in the Observatory has a larger collecting area (400 cm2 at 1 KeV) and significantly better angular resolution (.5'') than previous X-ray telescopes such as those on the Einstein and Rosat observatories. Instruments include a CCD Imaging Spectrometer, developed by Penn State and MIT, and a High Resolution Camera, built by the Smithsonian Astrophysical Observatory. After Space Shuttle deployment, rockets will boost the Chandra Observatory into an unusual elliptical orbit with apogee more than 1/3 the distance to the moon. This will allow it to spend most of its time above the earth's radiation belts. The Chandra X-ray Observatory Center (CXC), operated by SAO, will control science and flight operations of the Observatory. Excerpts from the NASA press release are given below. For more information see the Chandra Observatory Web Site at

NASA's Advanced X-ray Astrophysics Facility has been renamed the Chandra X-ray Observatory in honor of the late Indian-American Nobel laureate, Subrahmanyan Chandrasekhar. The telescope is scheduled to be launched no earlier than April 8, 1999 aboard the Space Shuttle Columbia mission STS-93, commanded by astronaut Eileen Collins.

Chandrasekhar, known to the world as Chandra, which means ``moon" or ``luminous" in Sanskrit, was a popular entry in a recent NASA contest to name the spacecraft. The contest drew more than six thousand entries from fifty states and sixty-one countries. The co-winners were a tenth grade student in Laclede, Idaho, and a high school teacher in Camarillo, CA.

``Chandra is a highly appropriate name," said Harvey Tananbaum, Director of the CXC. ``Throughout his life Chandra worked tirelessly and with great precision to further our understanding of the universe. These same qualities characterize the many individuals who have devoted much of their careers to building this premier x-ray observatory."

``Chandra probably thought longer and deeper about our universe than anyone since Einstein," said Martin Rees, Great Britain's Astronomer Royal.

``Chandrasekhar made fundamental contributions to the theory of black holes and other phenomena that the Chandra X-ray Observatory will study. His life and work exemplify the excellence that we can hope to achieve with this great observatory," said NASA Administrator Dan Goldin.

Widely regarded as one of the foremost astrophysicists of the 20th century, Chandrasekhar won the Nobel Prize in 1983 for his theoretical studies of physical processes important to the structure and evolution of stars. He and his wife immigrated from India to the U.S. in 1935. Chandrasekhar served on the faculty of the University of Chicago until his death in 1995.

The Chandra X-ray Observatory will help astronomers worldwide better understand the structure and evolution of the universe by studying powerful sources of X rays such as exploding stars, matter falling into black holes and other exotic celestial objects. X-radiation is an invisible form of light produced by multi-million degree gas. Chandra will provide x-ray images that are fifty times more detailed than previous missions. At more than 45 feet in length and weighing more than five tons, it will be one of the largest objects ever placed in Earth orbit by the Space Shuttle.

Jorge Pullin