It came sooo close to liftoff. More than 40 years in the planning, Gravity Probe B, a sophisticated experiment to test Einstein’s theory of general relativity (Farm Report, November/December 2001), was ready and waiting in a clean room at Vandenberg Air Force Base in central California in early December. NASA and Stanford engineers were all set to roll the spacecraft out to the launchpad, hoist it onto the Delta 2 rocket, close up the faring like a neat clamshell and start the countdown.
But the engineers had been hearing inexplicable noise—make that “bias”—on an external SQUID (superconducting quantum interference device). Rather than risk compromising the efficacy of the one-of-a-kind spacecraft, decision makers huddled and made the hard call to stand down and check out the problem. Like auto mechanics searching for an oil leak, Stanford workers slid underneath the spacecraft and unbolted the big black box that is the experimental control unit.
Physics research professor and long-distance runner Francis Everitt, who has guided the $650 million experiment since 1962 and weathered previous setbacks and Congressional threats to terminate funding, compared the latest interruption to the end of a marathon race. You get to a place where you can see the finish line, Everitt told colleagues, and while you’re making your final push, the judges pick up the finish line and move it five miles down the road.
The experimental control unit has now been replaced, and Gravity Probe B is once again good to go, scheduled for launch sometime between mid-April and the end of June. A website will be updated with the latest launch details every Friday: einstein.stanford.edu.
