[meteorite-list] Christmas Day Mars Landing (Beagle 2)

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu Apr 22 10:17:50 2004
Message-ID: <200312172305.PAA12719_at_zagami.jpl.nasa.gov>

http://science.nasa.gov/headlines/y2003/17dec_beagle2.htm

Christmas Day Mars Landing
NASA Science News
December 17, 2003

In search of alien life, the European Space Agency's Beagle 2
probe will parachute to the surface of Mars on Dec. 25th.

December 17, 2003: It's wintertime in the northern hemisphere of Mars,
and a flying saucer is about to land.

Back on Earth where it comes from, the craft is known as the Beagle 2,
sent to Mars by the European Space Agency in search of life. More
accurately, the Beagle 2 will be looking for chemical traces of
life--telltale signs that life once existed, or perhaps, exists right
now on the red planet.

Touchdown is scheduled for Christmas Day 2003. The Beagle 2 will precede
two NASA rovers, Spirit and Opportunity, slated to land in January.

Named after the ship that carried Charles Darwin, the Beagle 2 is a
self-contained laboratory shaped like a saucer, or a pocket watch, about
three feet in diameter. Although it carries many powerful scientific
tools, it weighs a mere 70 pounds. Being so light and compact, the
Beagle 2 was able to hitch a ride to Mars onboard the ESA's Mars Express
spacecraft launched last June.

While Mars Express, an orbiter, surveys the planet from a few hundred
miles up, the Beagle 2 will be able to stick its devices right into
Mars, sampling rocks and soil on the surface and below. NASA's Everett
Gibson, the interdisciplinary scientist for the Mars Express/Beagle 2
mission, explains: "We have two [ways] to get samples: a rock abrasion
tool, and a burrowing mole." Both are embedded in the Beagle's robotic arm.

"The rock abrasion tool goes right up against a rock, removes its
weathered surface, and can continue to go in and take out a little
core--about 20 to 100 milligrams of sample," he says. The ability to
remove the surface of a rock is important, as scientists learned when
NASA's Sojourner rover scrutinized Mars rocks in 1997. They all looked
much the same because their surfaces had been weathered by dusty winds
and solar radiation. Beagle 2 will be able to sample the variety that
lies within.

The other tool, "the mole," is able to reach as far as two meters from
the Beagle 2 and drill down about one and a half meters, gathering
samples in its hollow mouth. Just like the core samples collected from
inside rocks, Everett explains, soil found underground will have been
shielded from, and less altered by, solar ultraviolet radiation. In
these more protected samples, indications of life may be more likely to
exist.

As samples are collected, they'll be brought back into the Beagle and
heated in one of the lab's ovens. Gases released by this process will be
analyzed by a mass spectrometer.

The Beagle will check for biological signatures by, in part, looking
carefully at the types of carbon that it finds. Basically, carbon comes
in both a lighter variety -- carbon-12 -- and a heavier variety --
carbon-13. On Earth, things that are alive tend to prefer the lighter
kind. They use more carbon-12 in their metabolism. If the spectrometer
identifies a sample containing more carbon-12 than would be expected in
an inorganic sample of soil, that might be a sign that life had once
dwelled there.

The spectrometer will also check the atmosphere for traces of methane.
This gas can be produced by living creatures. On Earth it comes from
sources such as termites, cows, and swamps; on Mars it might come from
extreme-loving microbes. Methane on Mars should be destroyed quickly,
probably within a matter of months, by the planet's strong ultraviolet
radiation. This means that if Beagle 2 detects any methane, something
must have created it very recently. If the Beagle 2 can find methane,
says Gibson, "it will go a long way to answering that key question: Are
biological processes operating on Mars?"

------------------------------------------------------------------------

On December 19, the Mars Express orbiter will eject the Beagle. From
then on, the little laboratory is on its own.

On Christmas Day it will hit the Martian atmosphere at a speed of about
12 thousand miles per hour. The resistance of the atmosphere will begin
to slow it down, as a shield protects it from the heat of descent. A
series of parachutes will emerge, each slowing the Beagle even more. At
200 meters above the surface, three gas-filled airbags will inflate to
cushion its landing.

The Beagle is expected to touch down within the Isidis Planitia Basin.
The landing site is at a low enough elevation to allow Mars' thin
atmosphere enough time to slow the Beagle down. There are also some
indications that Isidis Planitia contains ice, making it a promising
place to look for signs of life.

Once the Beagle lands, it will open up, like a pocket watch. Four solar
panels will emerge, and begin charging its batteries. It will send a
signal saying that it's arrived.

"When the Beagle lands," says Gibson, "we won't know immediately,
because we have to wait till Odyssey passes over." Odyssey is a NASA
spacecraft that's been orbiting Mars for the past two years. "The signal
from the Beagle will hopefully be detected by Odyssey," says Gibson.
Odyssey will send that signal on. And, about four to six hours after the
Beagle lands, its first message should reach the Earth--hopefully the
first of many.

The Beagle will continue its mission for about six months, collecting
data and transmitting it back to Earth via the orbiters Mars Express and
Odyssey.

Stay tuned for more Science_at_NASA stories in the weeks ahead about NASA's
Mars rovers, Spirit and Opportunity, and the intriguing places they will
visit on the red planet.
Received on Wed 17 Dec 2003 06:05:11 PM PST