Chandra has crucial Institute involvement


The Chandra X-Ray Observatory was successfully launched into space on July 23, carrying with it two key instruments developed at MIT. Institute scientists share responsibility for managing the telescope's scientific observations at the Chandra X-Ray Observatory Center in Cambridge.

Chandra is the most powerful X-ray telescope ever developed to conduct scientific observations of the high-energy universe. It will be able to observe X-rays emitted from neutron stars, black holes, supernova and quasars. The instruments aboard Chandra are one hundred times more sensitive than any other X-ray telescope.

Chandra was successfully deployed from the space shuttle Columbia by astronaut Catherine G. "Cady" Coleman (SB in chemistry, 1983) who was also completing the 50th flight into space by an MIT graduate. Following deployment, the observatory successfully completed five burns of its propulsion system to place it in its planned orbit for scientific observations.

"I'm very proud of the fact that MIT's Center for Space Research [CSR] built two of the four science instruments on this world-class facility, and [that] we are participating in the science operations throughout the mission," said Professor Claude R. Canizares, director of the CSR. "It's been a long time getting here, but we have an extraordinary team and everyone is thrilled that so far things are working beautifully. Now we're breathlessly awaiting the first images and spectra that we expect within a few weeks.

"I'm convinced that Chandra will have a major scientific impact on many areas of astrophysics, from the study of black holes to the origin of the elements, the search for dark matter and the size of the universe. And the one thing that would surprise me most is not finding some big surprises -- new objects or phenomena that we have not yet imagined," Professor Canizares said.

The CCD Imaging Spectrometer (jointly developed by MIT and Pennsylvania State University), known as ACIS, produces extremely high-resolution images of the X-ray universe, capable of resolving 0.5 arc seconds over an eneergy spectrum of 0.2 to 10 keV. ACIS consists of two CCDs (charge coupled devices), one for imaging and one for use with the grating spectrometer. The instrument is capable of measuring both the position and the energy level or color of the X-rays it detects.

The principal investigator for ACIS is Professor Gordon Garmire at Penn State. Scientists from the Center for Space Research involved are Dr. George Ricker (deputy principal investigator), Dr. Mark Bautz (project scientist), Dr. William Mayer (project manager), and Robert Goeke and Edward Boughan (project engineers). The CCDs were fabricated at Lincoln Laboratory and tested at the CSR before being integrated into the ACIS instrument.

The other instrument developed at MIT is the High Energy Transmission Grating (HETG). The diffraction grating is inserted into the path of the X-rays between the telescope's mirrors and detectors and changes the path of the X-rays depending on their energy, making it able to produce high-resolution spectral information over an energy range of 0.4 to 10 keV.

Overseeing the HETG are Professor Canizares (principal investigator); the late Dr. Thomas Markert (project scientist); Drs. Mark Schattenburg, Daniel Dewey and Kathryn Flanagan (lead scientists); Eugene Galton (project manager) and Dr. Michael McGuirk (deputy project manager). Professor Henry I. Smith of the Department of Electrical Engineering and Computer Science is a co-investigator.

The Chandra X-Ray Observatory Center was established to plan scientific observations, process data received from Chandra and support scientists using the X-ray telescope. MIT is partnered with the Smithsonian Astrophysical Observatory in managing the CXC. Professor Canizares is associate director of the center; MIT's lead scientist for the center is Dr. David Huenemoerder, a research physicist at the CSR.

OPERATIONS CONTROL

The Chandra Operations Control Center, located in Draper Laboratory's Hill Building in Kendall Square, is responsible for controlling all flight operations of the Chandra observatory. This is the first time NASA has allowed the operations control of a major scientific spacecraft to be based outside a major NASA center.

Chandra is the third in a series of "great observatories" developed by NASA. The first was the Hubble Space Telescope launched in 1990, which operates in the visible and infrared portions of the spectrum. The second was the Compton Gamma Ray Observatory launched in 1991, which studies high-energy gamma rays. A fourth observatory, the Space Infrared Telescope Facility, is scheduled for launch in 2001.

A version of this
article appeared in the
September 11, 1999

issue of MIT Tech Talk (Volume
44, Number
2).


Topics: Space, astronomy and planetary science

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