Gravity probe, conceived in '59, finally launched

Satellite to test parts of relativity theory

April 21, 2004|By Gwyneth K. Shaw | Gwyneth K. Shaw,ORLANDO SENTINEL

WASHINGTON - An idea conceived when Dwight Eisenhower was president finally soared into orbit yesterday when NASA launched a satellite designed to test parts of Albert Einstein's theory of relativity.

It took decades of technological development and funding fights to get the $750 million satellite from the drawing board, where it began in 1959, to the launch pad at Vandenberg Air Force Base in California.

Gravity Probe B finally lifted off yesterday aboard a Delta 2 rocket, after a much-anticipated launch Monday was scrubbed because of a weather problem.

The final delay was a fleeting disappointment in a four-decade journey for the satellite, said Gaylord Green, program manager for the satellite at Stanford University, which is the probe's prime contractor for NASA.

But the successful launch "more than made up for it," said Green, who has worked on the project for 15 years. His tenure makes him a relative newcomer.

The project's lead scientist, C.W. Francis Everitt, moved to the United States from Britain in 1960 to spend a few years doing physics research. He has been a Stanford professor for 42 years, working toward yesterday's launch almost exclusively.

Gravity Probe B is only 21 feet long and a paragon of simplicity in a field in which spacecraft are usually crammed with instruments and gadgets. But the four gyroscopes at its core, suspended in a super-cold vacuum, will offer scientists' best opportunity ever to prove - or cast doubt upon - parts of Einstein's theory.

As the probe orbits 400 miles above Earth's two magnetic poles, the subtle movements of its gyroscopes will measure how space and time are "warped" by the orbit of the planet.

Gravity Probe B will test two parts of what Einstein theorized in 1916 - first, that the mass of an object, such as Earth, causes space to curve around it; second, that its rotation slowly drags space and time with it, a theoretical effect that has never been seen.

Once Gravity Probe B spends two months acclimating itself to space, scientists want to take measurements for a full year, as the Earth makes an orbit around the sun, plus another month for some overlap. It will probably take another year to fully analyze the results.

The satellite will be aligned with a distant star using a tracking telescope. Scientists will look for drift in the alignment of the spinning fused-quartz gyroscopes. If there is movement, they are expecting it to be minuscule - but even that will bolster Einstein's hypotheses.

The Orlando Sentinel is a Tribune Publishing newspaper.

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