Two
prototype spacecraft, one wielding
its own robotic arm, are poised to launch spaceward late Thursday on a
three-month mission to test methods for robotically refueling satellites in Earth orbit.
A United Launch
Alliance Atlas 5 rocket is slated to launch the two spacecraft,
collectively known as Orbital Express, and a clutch of microsatellites at 9:37
p.m. EST (0237 GMT) from Florida's Cape Canaveral Air Force Station [image].
The planned flight is part of the U.S. Air Force's Space Technology Program 1
(STP-1) mission.
"I think
we're feeling pretty good about it," USAF Lt. Col. Fred Kennedy, project
manager for Orbital Express, said in a telephone interview. "We're very
confident that we're going to have a nice successful mission."
Built for
the Defense Advanced Research Projects Agency (DARPA), the Orbital Express
vehicles are aimed at demonstrating autonomous spacecraft refueling and
servicing techniques [video,
image].
For
military uses, such capabilities would allow reconnaissance satellites to keep
station over specific areas of interest and tank up on vital propellant later,
though the technology could also aid general-use spacecraft in need of periodic
equipment repairs, replacements or an orbital boost, mission managers said.
"I think
it's extremely valuable for the entire space arena," Kennedy said of Orbital
Express' goal, adding that the mission could help ease the stringent
requirements of long-life satellites.
"Maybe you can accept a level of imperfection that will allow you to go up
later and perform upgrades and perform repairs, and put more propellant onboard
to get the job done. That will be a sea change in the way we do business."
Service
via automaton
The $300
million Orbital Express vehicles come in two forms: the smaller target NextSat
and the larger service spacecraft ASTRO [image].
Short for Autonomous Space Transport Robotic Operations, the ASTRO
servicing satellite is a 2,100-pound (952-kilogram) vehicle laden with 300
pounds (136 kilograms) of hydrazine propellant and measuring about six feet
(1.8 meters) tall and wide. Its robotic arm is designed to either latch onto
NextSat and pull it close for a manual docking, or transfer replacement
hardware, such as a battery, from ASTRO to the target vehicle.
The
500-pound (226-kilogram) NextSat, meanwhile, is a three-foot (about one-meter)
wide prototype for a next-generation satellite designed with in-flight
refueling and servicing in mind [image].
"Our goal
is to demonstrate on-orbit refueling, component exchange and satellite
repair--all without a human operator," James Lee, head of Automated
Rendezvous and Docking Projects at NASA's Marshall Space Flight Center, which developed
part of the autonomous navigation system to be used on Orbital Express.
That NASA
navigation system, first flown during the space agency's DART
autonomous rendezvous mission in 2005, and will be combined with Boeing-built
sensors, passive detection systems and computer software to allow ASTRO to keep
close tabs on NextSat, mission managers said.
"ASTRO
is most often flying itself," Kennedy said, adding that the vehicle is expected
to function with minimal intervention by flight controllers at Kirtland Air
Force Base in New Mexico. "We are basically sitting there waiting to watch for telemetry
and other data tot tell us, '"Did it work? Is there a problem? Do we need to
intervene?'"
During its planned 91-day
mission, the Orbital Express vehicles are expected to go through a two-week
checkout period, and then test initial refueling and equipment replacement
techniques -- while still mated to one another -- using ASTRO's robotic arm. A
series of more complicated rendezvous, robotic arm and servicing scenarios are
then due to follow throughout the remainder of the mission, DARPA officials
said.
"Wrapping
all this inside a software package that can understand what to do with all of
it, without significant intervention, has been both the struggle and serious achievement
here," Kennedy said.
Boeing
Phantom Works served as the primary contractor for Orbital Express' ASTRO
vehicle, while Ball Aerospace led NextSat's development.
Along for the Ride
Orbital
Express' Atlas 5 booster [image]
is not only expected to haul ASTRO and NextSat into orbit tonight. The rocket
is also carrying four experimental microsatellites to test a multitude of technologies
in low-Earth orbit for the U.S. Air Force.
- Cibola Flight Experiment: An experimental satellite smaller than an
armchair designed to test new power supplies, inflatable antennas and
other technologies for future spacecraft, according to the Los Alamos
National Laboratory.
- FalconSat- 3: An experiment-laden satellite built and
managed by U.S. Air Force Academy. It carries five military science
experiments to study space weather, with a focus on space plasma, and
spacecraft operations.
- MidSTAR-1: A multi-experiment satellite built by
midshipmen and personnel at the U.S. Naval Academy. It is carrying an
experimental microdosimeter, a nano-chemical sensor, as well as tests of
an Internet Communications Satellite payload and Configurable Fault
Tolerant Sensor.
- STPSat-1: A Space Test Program vehicle carrying several
experiments that include testing a high-resolution ultraviolet
spectrometer and studying irregularities in space-to-ground
communications, according to manufacturer AeroAstro, Inc.
"We come off first and then they start popping off, each of
the Air Force satellites in turn," Kennedy said of the STP-1 spacecraft
deployment plan. "We are ecstatic to be here and thrilled that we're going to
get an opportunity to prove out a new capability for the Department of Defense
and for the nation."
United
Launch Alliance will provide a live launch webcast of today's planned space
shot via the firm's website: http://www.ulalaunch.com.
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