Deploying
tiny probes to inspect or service spacecraft in distress and flying satellites
that can operate with limited human touch are the chief goals behind a
state-of-the-art technology demonstration mission successfully launched into Earth
orbit this morning.
The Air Force Research Laboratory's
Experimental Satellite System-11 craft reached space aboard a four-stage, $18
million Orbital Sciences Minotaur rocket. Liftoff occurred at 1335 GMT (6:35
a.m. local time; 9:35 a.m. EDT) from the Space Launch Complex 8 pad on the
southern edge of California's
Vandenberg Air Force Base.
Officials confirm that the
XSS-11 spacecraft separated from the launcher as planned and has begun its
initial activities.
"Everything looks
good," an Orbital spokesman said. "Early preliminary indications look
like (the satellite) is healthy. It was an accurate launch, right in the middle
of the box."
Over the coming weeks,
controllers will conduct a fundamental checkout of the satellite's main
systems.
The first real test of the
XSS-11's rendezvous sensors and technology is expected sometime in the next
three to six weeks when the craft revisits the Minotaur fourth stage.
"That is really where
we get the basic performance parameters for the sensors," said Harold
Baker, XSS-11 program manager at the Air Force Research Lab.
The mission will last 12 to
18 months as XSS-11 demonstrates new autonomous satellite features during
encounters with six or seven spent rocket stages and dead U.S.
satellites. The microsatellite project is designed to
test technologies that could allow quick visual examinations or maintenance of
spacecraft in orbit.
"This satellite
represents a significant advance of what's ever been done in space
before," Baker said. "Proving these technologies could have
considerable impact on the amount of money it takes to operate a satellite, to
launch a satellite, to build a satellite."
At the heart of XSS-11 is a
radiation-hardened Power PC 750 processor that serves as the master avionics
box, enabling onboard autonomous operations and mission planning by the
satellite itself.
"The real technology
is in the autonomous planner onboard and the logic algorithms that are required
to do that mission, as well as the ground tools," Baker said.
The U.S. military
has spent $56 million creating the XSS-11 spacecraft. Another $6 million has
gone into mission operations over the life of the program.
Ground controllers will be
actively involved in the early rendezvous attempts, but hope to gradually wean
XSS-11 from human intervention.
"From the beginning,
safety has been foremost in our minds. If we collide with an object, we fail.
So initially we let the planner plan, but it has many, many ground decision
points that have to be reached before it can proceed on its own," Baker
said.
"As
we proceed through the mission, we take some of those points out as we get more
confidence that the planner is doing the right thing and it's agreeing with
what we are seeing on the tools on the ground. As we go through the mission, we
will take more and more of those go/no go decision points out that are given
from the ground. The objective by the end of the program is have as many of
those, if not all those, out and tell it what you want it to do and have
confidence it is going to succeed."
In selecting the targets,
the objects must be American and within roughly the same orbit.
"All of the objects
are U.S.-owned, dead or inactive space objects. We have several rocket bodies
that have been expended for other space vehicles and two or three satellites
that are no longer operating....I believe one of them is a dead NOAA
satellite," Baker explained.
The exact mission length
will be determined as the mission proceeds.
"It really depends how
the objects work out as we go along," Baker said. "Fuel is the
limiting factor on the flight."
Some space watchers have
suggested that XSS-11 is actually testing anti-satellite, or space weapon,
concepts to disable enemy craft.
"Our job at the Lab is
to develop technology," Baker said. "This is really a demonstration
of autonomy technology, not weapons."
"We can say
categorically, there's nothing that ejects out of the satellite," said
Col. Richard White, commander of Space and Missile System
Center's Detachment 12.
"There's no battering ram. The entire purpose of the software, the entire
purpose of the mission, is to make sure -- I repeat -- not bump into
something."
During the rendezvous
events with the target objects, XSS-11 will close within 1.5-miles of a rocket
body or satellite but will never touch them.
"To fulfill our
requirements, we can do that from two-and-a-half kilometers away. Obviously, we
move in somewhat closer just to validate some of the technologies and how well
they perform," Baker said.
"If we collide with
something, we fail. We have multiple layers of safety on this satellite, literally we have three or four layers of safety
to make sure we don't collide with an object."
How the technology will be
used in operational missions of the future is yet to be seen.
"There is no specific
or direct military application. This is a technology demonstration. That is
what the Lab is for. We're really looking at the technologies, tools,
algorithms, how the onboard planner performs and validate those so that they
can be put into future plans," Baker said.
XSS-11 is one in a line of
demonstration test satellites. Air Force leaders will decide whether there
needs to be a follow-up to this particular mission.
"I think if this
flight is successful, we move some of this technology forward for future
mission planning. There are other areas to be developed, so there may be a follow-on. But that is not really how we do our programs.
"This
is one in a series of experimental satellites. Currently, we are planning the
next one. We receive proposals from different organizations on what they would
like to see and done in space. That goes to our high-level officers in the Air
Force and at Space Command, they get vetted and they select a new
demonstration. It doesn't have to be in the same area as this one, it could be
in a totally different area. We are right in the middle of that process now. In
the next three or four months, they will come out with what the next
demonstration is going to be."
Today's mission was third
for the Orbital Sciences-managed Minotaur rocket, which uses decommissioned
Minuteman 2 first and second stages and the upper two stages from commercial
Pegasus boosters. The first stage that propelled the six-story vehicle skyward
at sunrise this morning was built in 1967; the second stage dates to 1981.
"It's a great reuse of
old ICBM assets, taking those out of missile holes and using that to launch a
small satellite," White said.
Minotaur successfully
debuted in 2000, carrying out a pair of missions that lofted five small
satellites.
Schedules call for two more
Minotaur launches this year -- in July and December -- from Vandenberg. The
first will deploy the STP-R1 research satellite for the Air Force; the second
will carry spacecraft in the joint Taiwan-U.S. project called COSMIC to study
the atmosphere.
For
Vandenberg Air Force Base, today's launch was the site's first space mission in
2005. Next up is Orbital Sciences' air-launched Pegasus rocket with NASA's DART
technology satellite slated for flight on Friday.
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