April 15, 2004

GP-B

Status   (processing notes)

The team has resolved the short in the launch pad ground support equipment and is proceeding forward with a launch date of Monday, April 19, at 10:01:20 a.m. PDT.

The spacecraft was moved from the payload processing facility to Space Launch Complex 2 on Thursday, April 1 and mated to the Boeing Delta II rocket. A spacecraft state-of-health check was successfully performed. The Flight Program Verification was conducted on April 9. This was an integrated test of the Delta II vehicle and the Gravity Probe B spacecraft. The two-day operation to install the two halves of the payload fairing around the spacecraft is underway and was completed April 14. This is the final major spacecraft-associated activity to be performed before launch.

Two days of major activities remain to be performed. On Friday, the loading of the second stage with its complement of hypergolic propellants is scheduled. On Saturday, Flight Slews, which are launch vehicle engine steering checks, will be performed. The final Range Safety beacon checks also are scheduled.

Retraction of the mobile service tower, the gantry surrounding the Delta II, is scheduled to occur at 11:30 p.m. Sunday. Loading of RP-1, a highly refined kerosene fuel, aboard the first stage is scheduled to begin at approximately 7:30 a.m. Monday. Loading of the cryogenic liquid oxygen into the first stage will begin approximately an hour later.

The Gravity Probe B mission is a relativity experiment developed by NASA’s Marshall Space Flight Center, Stanford University and Lockheed Martin. The spacecraft will test two extraordinary predictions of Albert Einstein’s general theory of relativity that he advanced in 1916: the geodetic effect (how space and time are warped by the presence of the Earth) and frame dragging (how Earth’s rotation drags space and time around with it).

Gravity Probe B consists of four sophisticated gyroscopes that will provide an almost perfect space-time reference system. The mission will look in a precise manner for tiny changes in the spin axis direction. Gravity Probe B will be launched into a 400-nautical-mile-high polar orbit for a 16-month mission.

Government oversight of launch preparations and the countdown management on launch day is the responsibility of the NASA Launch Services Program based at John F. Kennedy Space Center. The launch service is provided to NASA by Boeing Launch Services.

MESSENGER

Status   (processing notes)

MESSENGER is at the Astrotech Space Operations facilities near Kennedy Space Center, where it is undergoing prelaunch testing. Testing of the spacecraft’s radio system uplink and downlinks through the KSC/JPL interface with the Deep Space Network (MIL-71) continues. Autonomy testing is also continuing. This verifies MESSENGER’s ability to operate on its own when not in direct contact with Earth. Installation of thermal blankets continues.

The spacecraft was moved from its current location in the hazardous processing facility, where it has been since arrival, to an adjacent non-hazardous payload processing facility on Tuesday. The remainder of its final assembly and testing will be completed there. The spacecraft will return to the hazardous processing facility when ready for fueling, spin balance testing and mating to the upper stage.

The erection of the Boeing Delta II launch vehicle on Pad 17-B is currently scheduled to begin on June 18 with the erection of the first stage.

MESSENGER was built for NASA by the Johns Hopkins University Applied Physics Laboratory in Laurel, Md.

Aura

Status   (processing notes)

NASA’s Aura spacecraft, the latest in the Earth Observing System (EOS) series, arrived at Vandenberg Air Force Base, Calif., on April 1 to begin launch preparations. Packed in a special shipping container, Aura was transported from Northrop Grumman Space Technology (NGST) in Redondo Beach, Calif.

The Spacecraft Aliveness Test was successfully completed on April 12. This test verifies the spacecraft’s state of health after its trip from Redondo Beach. This week, the Spacecraft Comprehensive Performance Test is underway. This is a test of Aura’s instruments and onboard systems.

The Delta II first and second stage have arrived at Vandenberg after successfully completing checkout at Cape Canaveral Air Force Station.

The erection of the Boeing Delta II launch vehicle on Space Launch Complex 2, located on North Vandenberg Air Force Base, is currently scheduled to begin on April 26 with the erection of the first stage. The second stage is planned for hoisting atop the first stage on April 28. Erection of the nine solid rocket boosters is scheduled for April 29 through May 1.

Aura’s four state-of-the-art instruments will study the dynamics of chemistry occurring in the atmosphere. The spacecraft will provide data to help scientists better understand the Earth ozone, air quality and climate change.
The EOS Aura satellite, instruments and science investigations are managed by NASA’s Goddard Space Flight Center in Greenbelt, Md.

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