Five years ago today — April 20, 2004 — NASA’s Gravity Probe-B spacecraft was launched by a Delta 2 rocket from Vandenberg AFB. The mission carried four gyroscopes that were
the most perfect spheres ever made by humans. If these ping pong-sized balls of fused quartz and silicon were the size of the Earth, the elevation of the entire surface would vary by no more than 12 feet.
according to this NASA page. The mission was designed to test Einstein’s theory of space-time, and especially the effects of a rotating mass like the Earth on space-time. It collected date for 17 months, but solar flares and other glitches corrupted some of the data according to this report.
In more recent launch news, the Indians launched an Israeli-built spy satellite and Sea Launch launched a military communications satellite for Italy.by