Erica Hupp/George Deutsch
Headquarters, Washington October 3, 2005
(Phone: 202.358.1753/1237)

Steve Roy
Marshall Space Flight Center, Huntsville, Ala.
(Phone: 256.544.0034)

News Release: 05-160

NASA'S Gravity Probe B Mission Completes Data Collection

Almost 90 years after Albert Einstein first postulated his general
theory of relativity, scientists have finished collecting data to put it
to a new, different kind of experimental test.

NASA's Gravity Probe B satellite has been orbiting the Earth for more
than 17 months. It used four ultra-precise gyroscopes to generate the
data required for this unprecedented test. Fifty weeks worth of data has
been downloaded from the spacecraft and relayed to computers in the
Mission Operations Center at Stanford University, Stanford, Calif.
Scientists have begun the painstaking task of data analysis and
validation, which is expected to take approximately one year.

"This has been a tremendous mission for all of us," said Francis
Everitt, Gravity Probe B principal investigator at Stanford. "With all
the data gathered, we are proceeding deliberately to ensure everything
is checked and re-checked. NASA and Stanford can be proud of what has
been achieved so far."

Launched on April 20, 2004, from Vandenberg Air Force Base, Calif.,
Gravity Probe B has been using four spherical gyroscopes to precisely
measure two extraordinary effects predicted by Einstein's theory. One is
the geodetic effect, the amount by which the Earth warps the local space
time in which it resides. The other, called frame-dragging, is the
amount by which the rotating Earth drags local space time around with it.

"The completion of the GP-B mission is the culmination of years of hard
work, training and preparation by the GP-B team," said Tony Lyons, NASA
GP-B program manager from NASA’s Marshall Space Flight Center in
Huntsville, Ala.

"We are proud to have been associated with this extremely significant
mission," said Bob Schultz, Lockheed Martin's Gravity Probe B program
manager. "Working with Stanford and NASA, we formed a powerful team to
develop the challenging technologies needed to take a giant step forward
in helping understand Einstein's theory of general relativity."

The Marshall manages the Gravity Probe B program. Stanford conceived the
experiment and is NASA's prime contractor for the mission. Stanford was
responsible for the design and integration of the science instruments
and mission operations. The university has the lead for data analysis.
Lockheed Martin Space Systems Company designed, integrated and tested
the space vehicle and built some major payload components.

Additional points of contact:

Bob Kahn, Stanford University, Calif.
phone: 650/723-2540

Buddy Nelson, Lockheed Martin, Sunnyvale, Calif.
phone: 510/797-0349

For information about Gravity Probe B on the Web, visit:

http://einstein.stanford.edu
and
http://www.gravityprobeb.com

For information about NASA and other agency programs on the Web, visit:

http://www.nasa.gov/home