David Aguilar
(617) 495-7462

Christine Pulliam
(617) 495-7463


CfA Press Release

For Release: October 19, 1999


A space experiment with major contributions from the Harvard-SmithsonianCenter for Astrophysics (CfA) in Cambridge, MA, has been selected forNASA's Medium-Class Explorer, or MIDEX, program, and scheduled tobe launched in 2004.

The Full-Sky Astrometric Mapping Explorer (FAME) is an Earth orbiting optical telescope that will gather information on 40 million stars in the Milky Way Galaxy with unprecedented measurement accuracy. For bright stars, positions will be determined to the equivalent of the width of a footprint on the Moon as seen from Earth (50 millionths of a second of arc). This exacting precision is central to the study of key issues of scientific and general interest including the existence of other "solarsystems," the size and age of the universe, and an investigation ofthe mysterious "dark matter" in our portion of the Galaxy.

The selection was made by Dr. Edward Weiler, NASA AssociateAdministrator for Space Science. According to Dr. Weiler, "FAME utilizesa solar sail instead of thrusters to provide the propulsive force needed tore-orient itself to scan the entire sky." This invention by the projectscientist,Dr. Robert Reasenberg of the CfA, increases the accuracy of the astrometricdeterminations and opens the way for a highly extended mission by eliminatinga major use of consumables. Further, according to Dr. Weiler,this invention continues "NASA's trend toward greatly lowered mission costsvia innovative mission planning and operations."

"FAME will increase by more than 1000-fold the volume of space in whichwe can determine the distances to stars. By using the parallax method, wewill directly determine the lower rungs of the 'cosmic distance ladder,'" says Dr. Reasenberg. "Further, the starcoordinates determined by FAME will be more than 20 times more accuratethan any available today, opening the way for a rich scientific yield from themission and producing a resource for future researchers."

"By measuring the wobbling of star positions, FAME will discover companions, including 'brown dwarfs' and giant planets," saysDr. James Phillips of the CfA, who serves as deputy project scientist."Because of the large number of stars FAME will observe, it will provide thefirst statistically useful survey of such companions and elucidate thetransitionregion between brown dwarfs and giant planets."

In addition to determining the positions, motions, and distances of the stars,this satellite will measure the brightness of stars in each of several colorbands, repeatedly during the mission, to achieve millimagnitude accuracy forbright stars. When combined with the distance measurements, thisphotometric information will permit a determination of stellar type andintrinsic brightness, and will contribute to an understanding of the evolutionofstars. FAME will contribute to the accurate inertial reference frame neededboth for studies of solar-system objects and by Gravity Probe B, which willtest the "frame dragging" predicted by general relativity.

Four other CfA scientists are participating in the FAME mission.Dr. John Geary is a member of the project team, to which he lendshis expertise on detectors. Drs. John Huchra, David Latham andIrwin Shapiro are members of the science team, and will conductscientific investigations with the FAME data. The FAME missionhas a significant educational component. The major portion of that will beconducted by the CfA Science Education Dept. under theleadership of Drs. Philip Sadler and Bruce Ward.

Led by Dr. Kenneth J. Johnston, Scientific Director of the U.S. NavalObservatory (Washington, D.C.), the FAME project is a collaborative effortamong the U.S. Naval Observatory, the Smithsonian AstrophysicalObservatory (Cambridge, MA), the Naval Research Laboratory(Washington, D.C.), and Lockheed Martin Missiles and Space (Palo Alto,CA).

For more information on FAME, visit its website at http://aa.usno.navy.mil/FAME. The NASA press release about this announcement is available at http://spacescience.nasa.gov as an October 14 entry.

Contact Information:

Robert Reasenberg, (617) 495-7108, rreasenberg@cfa.harvard.edu
James Phillips, (617) 495-7360, jphillips@cfa.harvard.edu

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