[meteorite-list] Long Odds, High Hopes For British Mars Probe

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu Apr 22 10:18:03 2004
Message-ID: <200312231716.JAA09577_at_zagami.jpl.nasa.gov>

http://www.chron.com/cs/CDA/ssistory.mpl/space/2315824

Long odds, high hopes for British Mars probe
By MARK CARREAU
Houston Chronicle
December 23, 2003

The long odds facing Great Britain's Mars-bound Beagle 2 spacecraft have not
dimmed Everett Gibson's enthusiasm one bit.

One of two Americans on Beagle 2's multinational science team, the
63-year-old planetary geochemist from NASA's Johnson Space Center is one of
the world's foremost experts on lunar soil and other extraterrestrial
materials. In 1996, Gibson was on a small team of scientists led by
colleague David McKay that offered controversial evidence for past Martian
life. The team claimed discovery of fossilized bacteria and signs of
biogenic waste lodged in the crevices of an ancient meteorite of Martian
origin.

The claim has since been largely rejected by other experts, who argue the
NASA-led team cannot eliminate the Earth as the source of bacteria in the
fallen meteorite or that natural processes unrelated to biological activity
were responsible for the traces of waste.

"Maybe we were right. Maybe we were wrong. But I think we were right," said
Gibson. "Beagle may give us a signature that may prove it even better."

Beagle 2 is the first of three U.S. and European robotic spacecraft that
will soon attempt to land on Mars. Part of the European Space Agency's Mars
Express orbital mission, the $68 million, 73-pound Beagle 2 lander was
developed to search for signs of present or past life in the planet's soil
and air, findings that would help to bolster the claims made by Gibson and
his teammates.

The British spacecraft was jettisoned from its Mars Express mothership on
Friday and will attempt a risky descent to the Martian surface late
Wednesday.

The historical odds of success are low.

Only three of the dozen spacecraft developed by the United States and the
former Soviet Union or Russia to land on Mars have successfully reached
their destination and carried out scientific tasks.

Beagle 2 is Britain's first attempt. The tiny lander carries no propulsion
system of its own and only a modest electrical power supply, so before it
could be released the Mars Express had to be lined up on a collision course
with the planet for last week's release. Mars Express will alter its
trajectory Wednesday to avoid an impact and steer into orbit around Mars.

Once on its own, Beagle 2 has just six days of battery power. If the lander
is to survive, it must descend to the Martian surface during that period and
deploy four disk-shaped solar panels to convert sunlight into much-needed
electricity.

"I know the risks, and I'm very optimistic. You have to be," said Gibson.
"You have a goal that, if it succeeds, has a wonderful payoff. That payoff
gives you answers to that question: Are we alone in the cosmos? There is no
greater question for a scientist to help answer."

Gibson and his associates knocked on that door seven years ago.

The potato-size Martian meteorite he helped to examine was recovered from
the Alan Hills region of the Antarctic in 1984 by the National Science
Foundation. Eventually the 4.2-pound rock made its way to the Johnson Space
Center for preservation and study.

Just one of 29 known fragments of Mars found on the Earth, the meteorite was
carbon-dated as being 4.5 billion years old. From their two years of
analysis, NASA experts determined the rock's origins were from the Martian
subsurface. Somewhere between 3.6 billion and 4 billion years ago, the rock
was shattered by a powerful blow from a meteor impact that cracked the
structure, allowing water to flow through the crevices and leave the
evidence of suspected microbial activity.

The Red Planet was struck again with an even more powerful blow by an
asteroid or comet 16 million years ago, the experts believe. The force this
time was enough to blast the fragment off of Mars and into an orbit around
the sun that crossed the Earth's path.

The meteorite fell onto the South Pole 13,000 years ago. The chemical
composition of air trapped in tiny globules in the meteorite matched those
in samples of the Martian atmosphere analyzed by NASA's Viking I and II
missions that landed on Mars in 1976.

Only one spacecraft has successfully landed on the Martian terrain since:
NASA's 1997 Pathfinder mission. Beagle 2 could be next, followed by NASA's
twin $410 million robotic geologists, Spirit and Opportunity, on Jan. 3 and
24.

Relying on parachutes and airbags to slow its descent and cushion its
landing, Beagle 2 will attempt to touch down at Isidis Planitia, a
900-mile-wide depression near the Martian equator that may once have served
as a reservoir for water.

If so, Isidis Planitia may host bacterial activity or its remnants within
reach of the stationary spacecraft's robot arm.

Equipped with a small laboratory, the probe will snatch, drill or dig for a
dozen small samples of Martian soil or rock with the mechanical limb. The
arm is equipped to reach out more than 6 feet and drill down more than 3
feet. Once tucked in a small oven within the lander and heated in oxygen,
the samples will release a byproduct, carbon dioxide gas.

An analyzing instrument will examine the gas samples for two chemically
stable forms of carbon, the isotope Carbon-12 with a dozen neutrons in its
nucleus and Carbon-13 with 13 neutrons. Biological processes on the Earth
prefer Carbon-12, and the presence of the lighter isotope on Mars would
imply the existence of living or dead microbes. Similar assessments are
planned to look for forms of hydrogen, nitrogen and oxygen favored by
biological activities on the Earth.

The lander's gas analyzer will also attempt a potentially more exciting
discovery by looking for the presence of methane. Another carbon-based waste
product, it could be a byproduct of current biological activity.

"If we detect traces of methane, it will be a major discovery," said Gibson.

With its very thin atmosphere, Mars has no way of blocking high levels of
the sun's ultraviolet radiation from reaching the planet's surface, where it
would wipe out most methane gas within a 300-year period. If Mars is now a
dead planet, experts should expect negligible concentrations of methane.

If the gas is present, the planet may be biologically active, though
researchers will have to rule out the possibility the methane is linked to
unseen volcanic processes.

Beagle 2 is the brainchild of Colin Pillinger, a planetary scientist at
England's Open University and a longtime colleague of Gibson.

Pillinger is credited with overcoming enormous obstacles to develop the
mission, not the least of which was finding novel means to finance it in a
country that has traditionally shunned space exploration.

"The whole idea was conceived by Colin, and with his tenacity he pulled it
off, getting the funding and getting a ride to Mars," said Gibson. "It's a
wonderful story in modern-day science."

But even with a successful landing, potential new obstacles await.

NASA's Viking I and II missions of more than a quarter century ago also
attempted life-detection experiments on Mars. Unfortunately, the otherwise
highly successful Viking missions failed on that score.

Pillinger's campaign to convince the European Space Agency to include Beagle
2 in its plans for a Mars orbiting probe called Mars Express began a year
after the 1996 Mars meteorite announcement. Eventually, the English
researcher earned a ride to Mars for his spacecraft -- but not the
financing.

Undaunted, he searched for and received financial support from unusual
segments of Britain's private sector. The McClaren Formula 1 auto racing
team furnished the high strength carbon composite aeroshell that will
protect the spacecraft as it descends into the Martian atmosphere. If it
lands successfully, the probe will announce its arrival with a series of
nine musical notes composed by Blur, a British rock band that became a
sponsor.

NASA chipped in as well. The British lander was tested earlier this year in
a vacuum chamber at NASA's Johnson Space Center, where some of the landing
conditions were simulated. NASA's Mars Odyssey spacecraft, an orbital sentry
that has been circling Mars since late 2001, is poised to relay news of
Beagle's landing back to Europe through the American global deep space
communications network.

Still, the $68 million investment was low by traditional aerospace
standards. The spacecraft does not have the normal backup hardware. The
solar power system is so modest that only one scientific instrument can be
operated at a time.

Nonetheless, Gibson plans a long stay at Beagle 2's European headquarters,
where he and Pillinger will serve as the mission's principal investigators.

"We are going to look under a rock, deep underground. I want to see the
difference between the outside and the inside of a rock," said Gibson. "I
hope we get some data that supports the idea Mars is not a dead planet. I
believe we will succeed."
Received on Tue 23 Dec 2003 12:16:44 PM PST