Outta here! After four Earth-bound decades, gravity experiment launches/GravityProbe B status report for 04/23/2004 (Forwarded)

News Service
Stanford University
Stanford, California

Contact:
Dawn Levy, News Service
(650) 725-1944,

April 20, 2004

Outta here! After four Earth-bound decades, gravity experiment launches
BY Dawn Levy

Airborne at last! Forty-five years after its conception and 41 years after its
initial funding, the Gravity Probe B (GP-B) experiment has finally launched. On
April 20 at 9:57 a.m., a Boeing Delta II rocket sent the probe 400 miles high
and into polar orbit from Vandenberg Air Force Base in Southern California.

"This is a great moment and a great responsibility, the outcome of a unique
collaboration of physicists and engineers to develop this near-perfect
instrument to test Einstein's theory of gravity," said Stanford Research
Professor Francis Everitt, co-principal investigator of the experiment with
Professor Emeritus Brad Parkinson. "We are very grateful for all the support we
have received at NASA and elsewhere for this exacting effort, truly a new
venture in fundamental physics."

A collaboration of Stanford, NASA and Lockheed Martin, the experiment will
provide the most accurate test to date of Einstein's General Theory of
Relativity. With a telescope aimed at a far-off guide star for reference, it
will check tiny changes in the direction of spin of four gyroscopes, the
roundest objects ever machined, spinning ping-pong balls of quartz coated with a
superconductor and chilled near absolute zero with superfluid liquid helium,
undisturbed by all forces save gravity.

The gyroscopes precisely measure two effects predicted by Einstein. One, called
frame dragging, posits that the revolving Earth drags time and space around with
it like a spinning dancer's body causes her skirt to swirl. The other, the
geodetic effect, says the Earth's mass warps local time and space like the
weight of a bowling ball would dent a mattress.

On April 19, 28 buses took about 1,000 onlookers -- GP-B staffers, their
families and friends, and the press -- from the Marriott Hotel in Buellton,
Calif., to a viewing area near the launch site. At Stanford, about 200 people
packed Cubberley Auditorium to watch a NASA broadcast of the event. When the
launch was scrubbed four minutes prior to liftoff due to high shear winds, a
collective groan waved through Cubberley. A visitor at Vandenberg described the
disappointment there as "palpable." The launch would be postponed by almost 24
hours.

The next day, winds were kind. To cheers and applause, the 126.5-foot-long
rocket lifted gently off the ground, first shedding six strapped-on solid rocket
motors, later jettisoning three more. The probe started to line up with its
guide star, IM Pegasi, and began its duty of circling the Earth every 97.5
minutes. Then it deployed solar panels to capture the sun's energy to run
various onboard electrical systems. "We have received initial data that
indicates all systems are operating smoothly," said GP-B Program Manager Rex
Geveden of NASA's Marshall Space Flight Center.

After checking and calibrating instruments for about two months, researchers
will collect scientific data for 12 months and perform additional calibrations
for two more months. Controllers will be able to communicate with the orbiting
spacecraft from the Mission Operations Center at Stanford. Then it will take
scientists about a year to analyze all the data. As Everitt said at a NASA
briefing in early April, "It's going to be a very dull experiment once it's got
going."

Einstein for our grandchildren

But Gravity Probe B wasn't dull in the making. It provided a challenge
captivating enough to engage and train hundreds of the best minds, including
Nobel Prize winner Eric A. Cornell; America's first woman in space, Sally Ride;
and professors at Harvard, Princeton, Stanford and elsewhere. It is the largest
producer of graduate students in the building of a space mission, according to
Anne Kinney, director of the Astronomy/Physics Division at NASA headquarters. As
of October 2003, the $700 million experiment had produced 78 doctorates in seven
departments at Stanford and 16 at other universities, 15 master's or engineer's
degrees, as well as research opportunities for about 300 undergraduates and 35
high school students.

Much of the technology needed to put Einstein to the test had not yet been
invented in 1959 when Leonard Schiff, head of Stanford's Physics Department, and
George E. Pugh of the Defense Department independently proposed to observe the
precession of a gyroscope in an Earth-orbiting satellite with respect to a
distant star. Toward that end, Schiff teamed up with Stanford colleagues William
Fairbank and Robert Cannon and subsequently, in 1962, recruited a 28-year-old
Everitt, who is now 69. Decades of interdisciplinary collaboration between
physicists and engineers turned their stardust dream into Earth-circling
reality. But not everyone lived to see the launch. Schiff died in 1971, Fairbank
in 1989.

"The test of relativity is very simple, but the details are a testimony to
perseverance," Parkinson said. That's because several parameters had to be held
to zero to create a near-perfect science instrument, such as zero gravitational
acceleration to create a drag-free environment. Micro-thrusters keep GP-B's
space vehicle in perfect Earth orbit and alignment with the guide star by
emitting gas puffs so small they're akin to about one-fiftieth of the breath
you'd puff to clean your eyeglasses, he said.

Gravity Probe B's collaborations have resulted in innovations including the
SQUID (for Super Quantum Interference Device), to monitor spin axis orientation,
and the world's most perfect gyroscopes, to measure angles so small they
correspond to the width of a human hair as seen from a quarter of a mile away.
They led to a new material to bond optical quartz and mechanical components so
as not to interfere with the workings of the science instrument. They spawned a
porous plug, since used in two other NASA missions, which allows helium to leave
the cement-truck-sized thermos housing the experimental apparatus. They resulted
in improved precision of a civilian Global Positioning System (GPS), now used to
automate tractor plowings and aircraft landings.

The experiment's greatest success may lie in its potential to bring new
knowledge, such as greater understanding of black holes and warped space-time.
In the 19th century, people probably wondered what good Maxwell's equations
were, Parkinson said at the early-April NASA press briefing. But today useful
evidence of his theories of electricity and magnetism are found in light bulbs,
television, the Internet and more. Similarly, Parkinson said, new knowledge
gained from Gravity Probe B may benefit our grandchildren more than ourselves.

Stanford, under NASA contract, conceived the experiment and is responsible for
the design and integration of the science instrument, as well as for mission
operations and data analysis. Lockheed Martin, a major subcontractor, designed,
integrated and tested the spacecraft and some of its major payload components.
NASA's Marshall Space Flight Center in Huntsville, Ala., manages the GP-B
program. NASA's Kennedy Space Center in Florida and Boeing Expendable Launch
Systems of Huntington Beach, Calif., were responsible for the countdown and
launch of the Delta II.

-30-

Relevant Web URLs:

* Gravity Probe B
http://einstein.stanford.edu/

*****

Don Savage
NASA Headquarters
(202) 358-1547

Steve Roy
Marshall Space Flight Center Media Relations Dept.
(256) 544-0034

Robert Kahn
Stanford University, Stanford, Calif.
(650) 723-2540

For release: 04/23/04

Status report no.: 04-118

Gravity Probe B status report

Gravity Probe B -- a NASA mission to test two predictions of Albert Einstein's
Theory of General Relativity -- is orbiting 400 miles above Earth, and all
spacecraft systems are performing well. Its solar arrays are generating power,
and all electrical systems are powered on. The spacecraft is communicating well
with its supporting satellite relay and ground stations. Launched April 20 from
Vandenberg Air Force Base, Calif., Gravity Probe B is managed by the Marshall
Center.

At 9:57:24 am Pacific Daylight Time on Tuesday, April 20, 2004, the Gravity
Probe B spacecraft had a picture-perfect launch from Vandenberg Air Force Base
in South-central California. The Boeing Delta II rocket hit the exact center of
the bull's eye in placing the spacecraft in its target polar orbit, 400 miles
above the Earth.

"The Gravity Probe B Mission Operations Team has performed very well during this
critical spacecraft activation period," said Tony Lyons, Gravity Probe B NASA
Deputy Program Manager from Marshall Space Flight Center in Huntsville, Ala.

"We're ecstatic," said Stanford Gravity Probe B Program Manager, Gaylord Green.
"We couldn't have asked for a better or more beautiful launch, nor a more
perfect orbit insertion."

At approximately one hour eleven minutes, the spacecraft's solar arrays
deployed, and shortly thereafter, the on-board cameras treated all viewers, via
NASA TV, to the extraordinary sight of the separation of the spacecraft from the
second stage rocket, with a portion of the Earth illuminated in the background.

After two days in orbit, all Gravity Probe B systems are performing as planned.
The solar arrays are generating power, and all electrical systems are powered
on. The spacecraft is communicating well with the Tracking and Data Relay
Satellite System (TDRSS) and supporting ground stations.

All four Gyro Suspension Systems have now been activated. In addition, a lift
check was successfully accomplished for gyros #2 and #3. "We've successfully
achieved the first of many upcoming steps in preparing these four gyroscopes for
science data collection," said Rob Brumley, Stanford Gravity Probe B Deputy
Program Manager, Technical. "We are all extremely gratified with the initial
performance of these gyroscopes in space, including the first ever levitation of
a Gravity Probe B gyro on orbit."

The spacecraft's Attitude Control System is maintaining initial attitude
control. Fine attitude control should be achieved when thruster calibrations
have been completed. After that, the ultra-precise science telescope will be
locked onto the Gravity Probe B guide star, IM Pegasi, to within a range of
1/100,000th of a degree.

"All of us on the GP-B team are very grateful for the tremendous support we have
received from NASA, Lockheed Martin, Boeing, and many others," said Francis
Everitt, Gravity Probe B Principal Investigator at Stanford University. "We're
off to a fine start, but we now have a great sense of responsibility to make
sure we do the science in the best possible way."

The spacecraft is being controlled from the Gravity Probe B Mission Operations
Center, located at Stanford University. The Initialization & Orbit Checkout
(IOC) phase of the Gravity Probe B mission is planned to last 45-60 days, after
which the 12-month science data collection will begin. This will be followed by
a two-month final calibration of the science instrument assembly.

NASA's Gravity Probe B mission, also known as GP-B, will use four ultra-precise
gyroscopes to test Einstein's theory that space and time are distorted by the
presence of massive objects. To accomplish this, the mission will measure two
factors -- how space and time are warped by the presence of the Earth, and how
the Earth's rotation drags space-time around with it.

NASA's Marshall Space Flight Center in Huntsville, Ala., manages the Gravity
Probe B program for NASA's Office of Space Science. Stanford University in
Stanford, Calif., developed and built the science experiment hardware and
operates the science mission for NASA. Lockheed Martin of Palo Alto, Calif.,
developed and built the GP-B spacecraft.

For supporting materials for this news release -- such as photographs, fact
sheets, video and audio files and more -- please visit the NASA Marshall Center
Newsroom Web site at:

http:// www.msfc.nasa.gov/news/