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The Mission

Rocket: Delta 2 (7920)
Payload: Gravity Probe-B
Date: April 20, 2004
Time: 1657:24 GMT (12:57:24 p.m. EDT)
Site: SLC-2W, Vandenberg Air Force Base, California
Satellite feed: AMC 9, Transponder 9, C-band

GP-B mission overview

Launch events timeline

Ground track map

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Gravity Probe-B flies
The Boeing Delta 2 rocket launches with NASA's Gravity Probe-B spacecraft from Vandenberg Air Force Base, California. (4min 16sec file)
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Umbilicals connecting the Delta rocket to the launch pad yank away as the vehicle lifts off. (175sec file)
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Tower view
Liftoff as seen from a camera mounted on the mobile service tower next to the Delta 2 rocket. (26sec file)
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Back side
A camera positioned on the back side of the Space Launch Complex-2 West provides this angle of liftoff. (19sec file)
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The Gravity Probe-B spacecraft is successfully deployed from the Delta rocket as seen by an onboard video camera. (2min 20sec file)
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Post-launch chat
An interview with NASA launch manager Chuck Dovale following the successful deployment of Gravity Probe-B. (2min 20sec file)
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Mission Status

The Payload

NASA's Gravity Probe-B is an exotic satellite mission to test aspects from Albert Einstein's general theory of relativity.

GP-B spacecraft overview

Learn about the experiment

An intro to general relativity

The Launcher

Boeing's workhorse Delta 2 rocket has flown more than 100 times, launching military, scientific and commercial satellites.

Delta 2 fact sheet

Learn about launch site

Archived Delta coverage


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Follow the countdown and launch of the Boeing Delta 2 rocket with NASA's Gravity Probe-B spacecraft. Reload this page for the very latest on the mission.

Read our earlier status center coverage.