NASA and JPL are sending RATS to Mars to work as field geologists. A
RAT is not quite a furry little friend, but rather a high-tech robot with
diamond teeth, called a Rock Abrasion Tool (RAT).
One RAT will ride on each of the twin Mars Exploration Rovers,
launching to Mars in the summer of 2003. These RATS will allow humans
to remotely "crack open" rocks on Mars for the first time in the
history of Mars exploration.
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Stephen Gorevan, Chairman, Honeybee |
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"This is terribly exciting, but it's a little intimidating because no
one has ever tried to get into a rock on Mars before," says
Stephen Gorevan. Gorevan is the chairman of Honeybee, the small
robotics contractor for the Rock Abrasion Tool that sits half a mile away
from ground zero in New York City. Gorevan explains that past Mars
missions to the surface had different science and technology objectives.
" The Viking landers in the 1970's scooped up dirt on Mars and the
Sojourner rover proved we could move around on Mars in 1997."
Digging into a rock is the next step for the maturing Mars program.
Bringing a rock back from Mars or sending a human geologist comes
with prohibitive costs, so sending the RAT is the next best thing. The
tool will enable scientists to peer inside a rock, where they can analyze
unweathered minerals and learn about the origins of rocks.
Rick Paynter, deputy lead for Quality Assurance on the Mars Exploration
Rover project at NASA's Jet Propulsion Laboratory, explains that the RAT
will help "peel off the orange rind" and reveal new
information about the evolution of Mars. It will also help with comparing
rocks on Mars to rocks on Earth.
How the RAT Runs
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View the RAT video |
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The Mars Exploration Rover will traverse Mars, find a rock that's
interesting, nuzzle up to it, and maneuver its robotic arm to press the
RAT up against the chosen rock. The RAT, which is the size of a soda can,
will shave away the top layers of the rock. That process may take
anywhere from 30 minutes to three hours to remove a round hole
about 45 millimeters (1.5 inches) in diameter and 5 millimeters
(1/8th inch) deep, depending on the texture of the rock.
It's more like an electric shaver than a drill, says Steve Kondos,
contract technical manager at JPL . "The difference is, the shaver
heads move in and out rather than being stationary - this takes less
power. Power, energy, and mass are precious on the rover, so in order
to be efficient, we shave the rock rather than drill it, which is power
intensive."
The RAT Brushes Its Teeth
After the RAT shaves off part of a rock, it scurries aside via a Dr.
Seuss-like arm device, which also holds a camera and chemical analysis
tools to explore the newly exposed rock layers. Before it goes to grind
another rock, it turns around and brushes its "teeth" against
a RAT brush that acts like a shoe polisher as the RAT "teeth"
spin against it to clear out leftover rock. The RAT is designed to grind
away one rock, but could shave up to as many as 10 rocks.
The RAT With the Right Stuff
Like any aspiring astronaut, the RAT must prove it has the right stuff
before it can launch. The Rock Abrasion Tool is the brainchild of Mars
Exploration Rover Principal Investigator , Steve Squyres of Cornell
University, Ithaca, NY. Gorevan of Honeybee says, "Squyres
thought of the need to expose a rock on Mars, and got us from point A to
point B. Our job has been to get from point B to point Z."
After winning the competitive instrument contract, the Honeybee team
has had to follow strict size, mass, and pressure requirements generally
dictated by the strength limitations set by the robotic arm. The Honeybee
team had to use its ingenuity to come up with the optimum way to provide a
mini crater in a martian rock. Gorevan says, "We cobbled and
cogitated together to test ideas, and we're at about point W on the
way to Z."
The RATs in NYC Now Have Motors
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Steve Kondos |
Rick Paynter |
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Last week, Steve Kondos and Rick Paynter from JPL hand-delivered to
Honeybee the motors that run the RATS. "We're really conservative
at JPL. The value of the instrument far exceeds the cost," says
Paynter. "We split the motors and carried them in different pieces
of luggage and took separate planes to New York City."
Now that JPL delivered the motors, "we have a clear path to
finish our environmental tests and 'shake and bake' the RAT."
"Shake and bake" is a process used by engineers to ensure
that instruments can withstand the intense vibrations and heat of launch,
the extraordinary impact of landing on Mars, and the strong radiation
exposure during interplanetary cruise. As time races toward launch, other
challenges still remain. "One surprise has been to find how much
dust is created by the RAT," explains Gorevan at Honeybee. As the
robot grinds away at a rock, it generates dust plumes and leaves
RAT "droppings" that can blow onto the solar arrays of the
rovers or the cameras.
"Honeybee's claim to fame in NYC is a long way from its new
role with Mars - they created the giant moving parts on the Coca-Cola sign
in Time Square," says Rick Paynter from JPL. Steve Kondos from JPL
calls the RAT people at Honeybee ingenious. "They are concerned
with cost and schedule milestones, and best of all, they are fun to be
with. Since we come from LA, the Honeybee team introduces us to
little known spots, like a deli where the bread is so good that Frank
Sinatra used to have loaves shipped from Manhattan to Hollywood
every week."
New York, 9/11, and Mars
"After September 11 happened, the first thought was how the team
at Honeybee was affected", explains Kondos. "We called
immediately, but of course couldn't get in contact with them."
Luckily, no one on the team was hurt.
NASA Headquarters just approved putting an American flag on the rock
shield of the Rock Abrasion Tool. "It's not the equivalent of placing
the American flag in the rubble pile, but it's something like that."
Kondos is quiet for a moment, then adds, "We're not stopping our
progress and hiding, we're rising to the stars."
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