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By Peter Rejcek
Mike Comberiate is a man who doesn’t lose count.
Maybe it’s a quirk of being a NASA “rocket scientist”
with the Goddard Space Flight Center (GSFC).
In rapid-fire dialogue, Comberiate proudly notes this
current trip to Antarctica marks his 99th project here
on an ongoing program dubbed COOLSPACE — Communications
Over Obscure Locations Special Purpose Advanced Communications
Equipment.
Distill that long title and you learn that Comberiate
and his colleagues determine how to communicate between
points A and B. The problem could be linking a phone call
between the north and south poles — or crossing outer
space from Earth to speak to robots exploring the surface
of Mars.
This time around, Comberiate and his team of engineers
and students are using a small robotic vehicle to test
a host of systems that NASA may use in future planetary
mission, as well as in more immediate operations like
a maintenance flight to the Hubble Space Telescope. The
project acronym in this case is GREAT (Goddard Robotics
for Exploration and Avionics Testing).
“It’s an engineering model which is being used
to test avionics that are flying on our Hubble missions,”
Comberiate explained of the tracked vehicle. “It’s
a mobile test bed.”
University students mentored by GSFC engineers like Comberiate
built the tank-shaped robot and its various systems. It
features a LADAR (Laser Detection and Ranging) scanner
that uses an infrared laser beam to create a 180-degree
image of the area in front of the robot. Each new scan
is electronically stitched into a depth-of-field map that
a remote operator can use to maneuver the robot around
obstacles.
The image created by the LADAR is not a true picture,
but a multi-colored abstraction that looks a bit like
the science fiction view from the perspective of the Predator
alien in the popular movie series. In the case of the
NASA robot, the different colors represent distance, and
the image is accurate to 1 millimeter in an 80-meter-deep
view.
A shakedown of the robot’s laser scanning system
indoors and outdoors near McMurdo Station went well. The
indoor images consisted of recognizable shapes, like people
and desks, with a variety of depths. The outdoor scans
were a little more boring, said Steve Strasburg, an electrical
engineering senior at George Mason University in Virginia.
“It’s very flat, few rocks and actually a lot
of ice in this case,” he said during a presentation
of the NASAbot to the McMurdo community. “It’s
similar to Mars in that it’s very flat. You have
different contours. The rover will be at angles at certain
times and you’re going to have to do a little work
to stitch everything together. … Overall, it gives
a very precise point map image of where everything is.”
The real tests took place farther in the field, at a
camp called New Harbor in the McMurdo Dry Valleys and
out on the Ross Ice Shelf. The objective was to have an
operator in the United States interface with the robot
through a complex communications system that ensures no
data are lost as the signal bounces thousands of kilometers
around the world.
The system is called the Delay/Disruption-Tolerant Networking
(DTN), which prevents loss of data due to interruptions
or long-haul delays in the connectivity link, Comberiate
said. DTN shuttles information from one “node”
in the communications link to the next until it reaches
the end point. Comberiate likened it to a UPS delivery
system that allows him to track the data package along
its route.
“The end-to-end link to the USA has a long delay
and is subject to unpredictable dropouts,” he explained.
“[The National Science Foundation] and NASA need
to deal with this situation as we attempt to do more sophisticated
science in extremely remote locations.
“These long-haul connections are pretty realistic
for anything that you could do on Earth,” he said
of the Antarctic test scenario in the Dry Valleys.
Another experiment involves the “Space Cube,”
a new processing system using commercially available parts
that can withstand severe space radiation without degrading.
The system, which can fit in the palm of your hand, consists
of four personal computers that can be reconfigured remotely
— a Radio Shack-worth of hardware in a Rubik’s
Cube-sized box.
“The architecture is such is that they’re rad
tolerant — they don’t get destroyed by the radiation,”
Comberiate said. “We are testing its ruggedness in
extreme environments. It appears to have direct application
in autonomous, unmanned science instrumentation …
left in Antarctica or in the north polar region.”
Post-Antarctic plans will take the team to Barrow, Alaska,
where it will demonstrate the instruments to International
Polar Year scientists working in the Arctic.
“Whatever we can do here will help us with the flight
program because it costs a lot of money to simulate things,”
Comberiate said. “We’re doing it here in a world
that is very similar.”
It’s a world that Comberiate has visited on and
off for the last 25 years, a place where he has helped
pioneer communication milestones from Antarctica, including
the first Pole-to-Pole phone call using NASA’s original
Tracking and Data Relay Satellite (TDRS-1) to connect
to the South Pole to the North Pole in 1999.
The satellite’s high-speed connectivity was also
instrumental in 1998 at the South Pole Station when during
a teleconference doctors in the United States guided a
welder through a real operation on the station’s
doctor, who had been diagnosed with breast cancer.
For Comberiate, who once built instruments that landed
on the moon during the heady days of the space race, working
in Antarctica offers him the opportunity to keep the pioneering
science spirit alive.
“I can make more of a personal impact in Antarctica
because when you’re working on the moon, there are
so many people involved that if you die, it still goes
on anyway,” he said.
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Antarctic
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