[meteorite-list] Sending RATs to Mars

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu Apr 22 09:50:30 2004
Message-ID: <200204292117.OAA04980_at_zagami.jpl.nasa.gov>

http://mars.jpl.nasa.gov/spotlight/rat01.html

Sending RATs to Mars
Jet Propulsion Laboratory
April 29, 2002

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.

"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.

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."

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."
Received on Mon 29 Apr 2002 05:17:29 PM PDT