July 28, 2004

MESSENGER

Status   (processing notes)

On Tuesday, July 27 at Pad 17-B, the two halves of the Delta payload fairing were placed around the MESSENGER spacecraft. The securing of the fairing is being completed today. The Flight Readiness Review is scheduled for Thursday, July 29.

The spacecraft was transported July 21 from the Astrotech payload processing facility to Pad 17-B on Cape Canaveral Air Force Station and hoisted atop the Delta II. A spacecraft state-of-health check was then successfully performed, followed by the start of close-out activities for launch. The Flight Program Verification, an integrated test of the launch vehicle and the spacecraft, was successfully completed July 24.

On Friday, July 30, the loading of the second stage with its complement of hypergolic propellants is scheduled. On Saturday, July 31, Flight Slews which are checks of the launch vehicle steering system, will be performed. The final Range Safety beacon checks are also scheduled.

For launch, retraction of the mobile service tower that is the gantry surrounding the Delta II is scheduled to begin at approximately 4:30 p.m. Sunday, Aug. 1. Loading aboard the Delta first stage of RP-1, a highly refined kerosene fuel is scheduled to begin at 11:36 p.m. The cryogenic liquid oxygen will be loaded aboard the first stage approximately one hour later.

The launch weather forecast calls for a 30% chance of not meeting the launch weather criteria on Monday morning. At the 2:16 a.m. launch time the temperature will be near 79 degrees, the relative humidity near 90%, southeast winds at 8-12 knots, the visibility 10 miles or greater. There is a chance of thunderstorms in the vicinity, primarily offshore.

MESSENGER was built for NASA by the Johns Hopkins University Applied Physics Laboratory in Laurel, Md. The launch period extend through Aug. 14.

DART

Status   (processing notes)

On the Pegasus XL launch vehicle, the aft skirt has been installed. The fins are mechanically mated and alignment continues. The GPS and UHF antennas have been installed. Installation of fillet, material that acts as an interface between the first stage and the wing of the Pegasus, is currently undergoing installation. The Demonstration of Autonomous Rendezvous Technology (DART) spacecraft was rotated from horizontal to vertical and lifted onto a test stand July 27 for further launch processing activities.

The DART spacecraft arrived at Vandenberg Air Force Base on July 13 to begin final preparations for launch. The spacecraft’s Reaction Control System (RCS) has been charged with gaseous nitrogen and leak checks are underway.

DART has been designed and built for NASA by Orbital Sciences Corporation as a flight demonstrator to locate and maneuver near an orbiting satellite. The DART spacecraft weighs about 800 pounds, is nearly 6 feet long and 3 feet in diameter. The Orbital Sciences Pegasus XL vehicle will launch DART into a circular polar orbit of approximately 475 miles.

The DART satellite is an advanced flight demonstrator that provides a key step in establishing autonomous rendezvous capabilities for the U.S. Space Program. While previous rendezvous and docking efforts have been piloted by astronauts, the unmanned DART satellite will have computers and cameras to perform all of its rendezvous functions.

Once in orbit, DART will rendezvous with a target satellite, the Multiple Paths, Beyond-Line-of-Site Communications (MUBLCOM), also built by Orbital Sciences and launched in 1999. DART will then perform several close-proximity operations, such as moving toward and away from the satellite using navigation data provided by onboard sensors. The entire mission will last only 24 hours and will be accomplished without human intervention. The DART flight computer will determine its own path to accomplish its mission objectives.

DART is designed to demonstrate technologies required for a spacecraft to locate and rendezvous, or maneuver close to, other craft in space. Results from the DART mission will aid in the development of NASA’s Crew Exploration Vehicle (CEV) and will also assist in vehicle development for crew transfer and crew rescue capability to and from the International Space Station.

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