[tt] NYT: Perseverance Is Paying Off for a Test of Relativity in Space

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Perseverance Is Paying Off for a Test of Relativity in Space
http://www.nytimes.com/2009/02/17/science/17gravity.html

By GUY GUGLIOTTA

STANFORD, Calif. -- For 46 years, Francis Everitt, a Stanford
University physicist, has promoted the often perilous fortunes of
Gravity Probe B, perhaps the most exotic, "Star Trek"-ish experiment
ever undertaken in space. Finally, with emergency financial help
from a pair of unusual sources, success is at hand.

Conceived in the late 1950s, financed by $750 million from NASA and
launched into orbit in 2004, the Gravity Probe B spacecraft has
sought to prove two tenets of Einstein's theory of general
relativity. The first, called the geodetic effect, holds that a
large celestial body like Earth will warp time the way a rubber
sheet stretches when a bowling ball is placed on it. The second,
known as frame-dragging, occurs when the rotation of a large body
"twists" nearby space and time; turn the resting bowling ball, and
the rubber sheet twists.

To measure these phenomena, Dr. Everitt and his Stanford team
equipped Gravity Probe B with a special telescope attached to
several gyroscopes. They pointed the telescope at a "guide star," IM
Pegasi, and then spun up the gyros with their axes also fixed on the
guide star. If Einstein was right, the gyros would drift slightly
over time to follow the space-time distortion.

The Stanford team collected 11 ½ months' worth of transmissions from
Gravity Probe B, but tiny unforeseen drift in the gyros fouled the
results. Dr. Everitt had to ask NASA for extra time and money so his
11-member team could figure out how to scrub the data.

Four painstaking years later, the team has confirmed the geodetic
effect and put a credible frame-dragging result within reach.
Nevertheless, NASA was forced to stop financing the project last
May. This 11th-hour catastrophe might have been terminal, but Dr.
Everitt, long known for his tenacity as well as his charm, had
nursed Gravity Probe B through several near-death experiences over
the years.

To persevere into 2008, he had already won a $500,000 contribution
from Richard Fairbank, the founder and chief executive of Capital
One Financial and the youngest son of his old mentor, the Stanford
physicist William Fairbank. Richard Fairbank stipulated that
Stanford and NASA each match his contribution, and they did.

But by mid-2008, that $1.5 million was running out. That is when Dr.
Everitt turned to Turki al-Saud, vice president for research
institutes at the King Abdulaziz City for Science and Technology in
Saudi Arabia and a member of the Saudi royal family. Dr. Saud, who
has a doctorate in aeronautics and astronautics from Stanford,
arranged a $2.7 million grant. The work goes on.

"I didn't imagine I would ever visit Riyadh," Dr. Everitt said. "We
will need more money, but $2.7 million by itself is really helpful.
We now have a clear end in sight."

The Gravity Probe B experiment was conceived at the dawn of the
Space Age by the Stanford physicist Leonard Schiff and George E.
Pugh of the Defense Department. Dr. Schiff brought William Fairbank
into the project in 1959, and in 1962 Dr. Fairbank induced the
British-born Dr. Everitt to come for a visit. Now 74, Dr. Everitt
has directed Gravity Probe B ever since.

While the experiment itself was relatively straightforward, the
engineering demands were unprecedented. The theoretical distortion
in space-time for the geodetic effect was 6,614.4 milliarcseconds
per year; for frame-dragging it was only 14 milliarcseconds per
year. A milliarcsecond is about one four-millionth of a degree of
arc.

To make measurements that fine using an object as large as Earth,
the spacecraft's gyros had to be virtually friction-free and
unaffected by heat, magnetic fields or unpredictable movements. The
pristine environment of space made the attempt possible.

But success was not guaranteed. Arcane, often unprecedented
technologies were needed. The four fused-quartz, Ping-Pong-ball-size
gyroscopes, coated with the metal niobium, were the most perfectly
spherical objects ever created by humans. A coffin-size lead "bag"
shielded the gyros from Earth's magnetic field.

A large thermos-like container called a dewar contained 645 gallons
of liquid helium to be cooled to within two degrees of absolute
zero. The helium held the niobium coating at superconducting
temperatures, so the metal could track the deviations in the gyros'
spin axis.

By the time the 21-foot-long, 3-ton spacecraft was launched on April
20, 2004, Gravity Probe B had become a very expensive tool designed
to prove something that many scientists over the years had come to
accept as already proved by theoretical physics and some previous
experiments.

That argument has no heft with Dr. Everitt. "We are doing a
measurement with a massive object, and this is valid," Dr. Everitt
said. "This is what the general theory of relativity says, and this
is the experiment."

The mission, however, did not go according to plan. The niobium
coating on the gyros and their housings was slightly uneven, causing
tiny unpredictable electrical torques that made the gyros drift. The
mission ended in 2005, but since then the Stanford team has been
mapping niobium anomalies on each gyro, finding the patterns of
distortion and subtracting the noise from the data.

NASA had budgeted money for a year's worth of post-flight data
analysis, but Dr. Everitt needed a lot more time, and NASA financed
the project through 2007. That, it seemed, would be the end.

Richard Fairbank, whom Dr. Everitt had known since he was a child,
thought differently. "Nearly 50 years ago, my father had talked with
me about the integrity of a bold quest and never giving up," Mr.
Fairbank said. "I just felt that the project was on the 1-yard
line."

The financing brought about by his contribution took the project
into 2008, but in May, Gravity Probe B went before NASA's senior
review, where an independent committee of scientists rates
continuing agency projects to determine financing priorities. "We
ended up dead last," Dr. Everitt said.

That month, however, Dr. Saud visited Stanford and spoke briefly
with Dr. Everitt. Saudi Arabia, which has built 12 small satellites,
"was interested in forming partnerships" for future space missions,
Dr. Saud said in a telephone interview, and has since done so with
Stanford and NASA. Dr. Everitt met with Dr. Saud in London in July,
and Gravity Probe B received $2.7 million.

The team has forged ahead. In August, graduate students made a
breakthrough in data analysis to bring the frame-dragging deviation
within 15 percent of the predicted result. Dr. Everitt hopes to get
it within 3 percent by mid-2010. The geodetic effect is currently
within 1 percent of the predicted result and is expected to go even
lower.

"They fly the mission and have what seems like an insurmountable
problem," said Michael Salamon, program scientist for the Physics of
the Cosmos Program at NASA and a staunch supporter of the project
despite the senior review decision. "Then they do this. It's
spectacular, frankly, and when it's done we are going to have a
press announcement."