It will test two predictions in Einstein's General Theory of Relativity -- that massive bodies such as Earth warp space and time, and that such bodies drag space-time with them as they rotate. If Einstein was right, physicists and cosmologists will heave huge sighs of relief. If he was wrong, they'll have to question their core beliefs about the expanding universe.

The test uses extremely uniform spinning quartz balls that are the heart of four liquid-helium-cooled gyroscopes. Scientists will point the satellite's small telescope at a distant "guide star" and align these spinning gyros. And then, for the next 18 months as the satellite orbits 400 miles above Earth, they'll look, very precisely, for tiny changes in the gyros' spin.

Stanford scientists asked UA optical sciences Professor Emeritus Stephen Jacobs to test several candidate samples of fused quartz materials from which to fabricate the perfectly spherical quartz balls, or "rotors."

"They wanted to be sure they were using the best quartz samples they could get their hands on," Jacobs said. Researchers in his Dimensional Stability Lab used advanced laser technologies to test thermal expansion and other properties of the quartz. "Ours was a small but important role," Jacobs said.

Stanford also awarded the Optical Sciences Optics Laboratory another important piece of the experiment -- the job of polishing the 75-pound quartz block that holds the four gyroscopes. Two previous polishing attempts at other facilities failed.

Optics Lab manager Martin J. Valente and his team successfully polished the 22-inch long, 7.25-inch-diameter quartz block that holds the gyros. They also produced a second, identical block in 1998 for flight backup.

"We're very proud of what we were able to do," Valente said. "This was an extremely challenging project -- one that had not been done before."

UA researchers spent 14 months grinding and polishing the blocks to exacting specifications. The block face on which the telescope sits is polished to within 2.5 millionths-of-an-inch, peak to valley. The other block faces were polished to a smoothness of 7 millionths-of-an-inch.

But the greatest challenge came in holding very tight angular tolerances between the block faces, Valente said. Two side surfaces had to be within 5 arc seconds of one another and within one arc second of the front face. (An arc second is one-3,600th of one arc degree. There are 360 arc degrees in a circle.)

To achieve this precision, the UA team measured angles with a reflective device called an "autocollimator" and with some auxiliary optics called "optical squares."

Optics lab technicians had to polish the surfaces by hand because machines are not precise enough. Also, lab temperatures had to be kept to within a single degree Fahrenheit during polishing operations.

Valente will fly to Vandenberg Air Force Base, Calif., to watch the satellite ride into space aboard a Delta 2 rocket. The launch is scheduled for 1:01 p.m. EDT (10:01 a.m. MST) on Monday.

"It's going to be great to see the experiment go up, good for us, and for the UA, " Valente said.

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