Gravity Probe B launch slated for Tuesday :: Namibia Internet Gateway cc ::

Articles: Gravity Probe B launch slated for Tuesday

Posted by admin on Tuesday, April 20, 2004 - 02:29 AM

The launch of a probe designed to test several aspects of Einstein's theory of general relativity is slated to launch Tuesday afternoon, a day after high winds postponed a planned liftoff from Vanderberg Air Force Base.
Minutes away from the liftoff of NASA's Gravity Probe B spacecraft from Vandenberg Air Force Base, Boeing Launch Services mission director Rich Murphy called a hold in the countdown, effectively cancelling Monday's launch. The launch had just four minutes left to go when Murphy called the hold. High upper level winds had plagued the countdown despite otherwise clear weather conditions and launch officials could not verify whether the proper flight profile was loaded onto the spacecraft to guide it through the wind disturbance. Already on its own internal power, Gravity Probe B was scheduled for a 1:01:20 p.m. EDT (1701:20 GMT) liftoff, but had only a one-second window to launch and be properly aligned with its guide star once it reached space. The launch is now delayed 24 hours until 12:57:24 p.m. EDT (1657:24 GMT) April 20. This marks the second launch delay in a week for Gravity Probe B, which was scheduled to liftoff April 17. Officials scrubbed that launch to fix a short circuit in remote monitoring equipment for the probe's battery voltage. There were no mechanical problems during today's countdown. The Boeing-built Delta 2 rocket is expected to launch the spacecraft into a 400-mile Earth orbit for a 16-month mission. A collaboration between NASA and Stanford University, the Gravity Probe B mission is designed to test two principles set by Albert Einstein in 1916 by his general theory of relativity. Once in orbit, the spacecraft will measure tiny variations in the spin of four onboard spherical gyroscopes — each the size of a ping-pong ball — to test how the Earth's presence warps the space and time around it, which is called the geodetic effect. The probe will also look for evidence of frame-dragging, the tendency of the Earth's rotation to drag space and time around the planet as it turns.

· 129 Reads ·