The
Pegasus XL launch vehicle’s fourth stage has arrived
and the initial testing has been completed. It is a hydrazine
fuel upper stage that will be mated to the satellite.
Later the combination will be integrated with the Pegasus.
In other work, the aft skirt has been installed. The
fins are mechanically mated and alignment continues.
The GPS and UHF antennas have also been installed. Installation
of fillet, material that acts as an interface between
the first stage and the wing of the Pegasus, continues
to undergo installation.
The Demonstration of Autonomous Rendezvous Technology
(DART) spacecraft was rotated from a horizontal to vertical
position 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 Advanced Guidance Sensor (AVGS) hardware, the primary
technology demonstration experiment for the satellite,
is completing final testing at the Marshall Space Flight
Center in Huntsville, Ala. The optical characterization
testing and final performance verification test will
be conducted this month. The AVGS will be shipped to
Vandenberg for installation aboard the satellite in early
September.
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 and will also assist in vehicle development
for crew transfer and crew rescue capability to and from
the International Space Station. |