[meteorite-list] Mars Rover Seeks Treasure in Trash

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Wed Dec 29 16:10:10 2004
Message-ID: <200412292110.NAA04586_at_zagami.jpl.nasa.gov>

http://rockymountainnews.com/drmn/state/article/0,1299,DRMN_21_3431430,00.html

Mars rover seeks treasure in trash

Engineers scavenge for ideas in charred debris of heat shield

By Jim Erickson
Rocky Mountain News
December 29, 2004

Sure, pictures of Mars rocks are pretty cool. If you like rocks.

But if you want to get aerospace engineers really excited, show them
photos of the charred, crumpled remains of their own hardware sitting on
the surface of another planet.

That's what NASA's Opportunity rover is doing right now. The six-wheeled
explorer is snapping close-ups of the battered heat shield that carried
Opportunity safely through the Martian atmosphere on landing day, Jan.
24, 2004.

The heat shield was built at Jefferson County's Lockheed Martin Space
Systems, in a partnership with NASA's Jet Propulsion Laboratory in
Pasadena, Calif.

"When people saw images of a piece of hardware - something that wasn't a
rock - everyone got real excited," said Ben Thoma, a JPL mechanical
systems engineer who worked on the Mars Exploration Rover mission.

"Everyone is really excited to be able to see a picture of their own
hardware, that they helped design, lying broken up on the surface of
another planet," Thoma said Tuesday.

After nearly a year of exploring the surface of Mars with its twin,
Spirit, the Opportunity rover is now on a multiweek campaign that is
driven by engineering questions rather than scientific ones.

The engineers want to know how well the heat shield performed during the
spacecraft's fiery entry. They hope to glean clues to help them design
more efficient and lighter-weight heat shields for future missions, said
Bill Willcockson, head of the entry systems group at Lockheed Martin
Space Systems.

The company has been making heat shields for NASA interplanetary
spacecraft since the 1970s. But this is the first time that engineers
have been able to inspect their handiwork after the plunge to another
planet.

Opportunity rode to the surface of the Martian plain known as Meridiani
Planum sealed inside a cocoon called an aeroshell. The aeroshell has two
parts: a forward-facing heat shield and a backshell.

The surface of the heat shield is coated with a protective layer
six-tenths of an inch thick. The coating is made from the outer bark of
cork oaks, ground to a powder and mixed in a vat with tiny glass spheres
at Lockheed Martin's Waterton Canyon plant southwest of Denver.

On Jan. 24, the Opportunity rover's aeroshell slammed into the Mars
atmosphere at about 12,000 mph. The heat shield glowed white-hot,
reaching an estimated temperature of 2,600 degrees.

About four miles above the Martian surface, after the aeroshell deployed
its parachute, the heat shield was jettisoned. It hit the ground at
about 170 mph and bounced, spliting into two large chunks and scattering
smaller bits of debris.

The Opportunity rover is now 18 feet from one of the two big chunks,
said Christine Szalai, a JPL flight systems engineer who worked on the
heat shield.

In the days ahead, the rover will pull up alongside the wreckage, extend
its robotic arm, and take close-up pictures of cracks in the heat
shield, she said.

The heat shield's cork-and-glass coating was designed so that its outer
third would char during the aeroshell's fiery entry.

Engineers want to measure the depth of the charred layer on
Opportunity's heat shield to determine if future Martian heat shields
can be built a bit thinner and lighter, Willcockson said.

Taking the heat

The heat shield was built at Jeffco's Lockheed Martin Space Systems and
consists of:

o A surface coated with a protective layer, six-tenths of an inch thick.

o The protective coating is made from the outer bark of cork oaks,
ground to a powder and mixed in a vat with tiny glass spheres.
Received on Wed 29 Dec 2004 04:10:03 PM PST