spacetoday.net: Gravity Probe B launched

Posted: Tue, Apr 20, 2004, 8:16 PM ET (0016 GMT)
Delta 2 launch file photo (Boeing)

A Delta 2 successfully launched NASA's Gravity Probe B mission on Tuesday after years of delays. The Delta 2 7920 lifted off from Space Launch Complex 2W at Vandenberg Air Force Base, California, at 12:57:24 pm EDT (1657:24 GMT), during a one-second launch window. The spacecraft separated from the booster's second stage 75 minutes after liftoff, entering a polar orbit approximately 640 kilometers in altitude. The launch of the spacecraft was delayed one day when launch controllers could not confirm that the proper upper altitude wind profile data had been properly entered into the vehicle's computers; other problems with the spacecraft delayed its launch for several years. Gravity Probe B, whose origins date back more than four decades, will be used to confirm one aspect of Einstein's general theory of relativity during its 16-month mission. The spacecraft was built by Lockheed Martin at a total mission cost of over $700 million.