An Earth invasion force sets its sights on Mars

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An Earth invasion force sets its sights on Mars

Against long odds, a fleet of spacecraft will search Red Planet for signs of
life

By Michael Stroh
Sun Staff

June 1, 2003

Mars, beware - the Earthlings are coming.

A sweeping scientific assault on the Red Planet will commence in coming weeks as
an international flotilla of spacecraft blasts off to study Mars and scour it
for signs of life.

If all survive - hardly a sure thing, given the planet's reputation as a
graveyard for probes - four satellites and three ground-based robots will be
sifting the planet for secrets by late January, the greatest concentration of
scientific hardware ever assembled on another planet.

"It's going to look like a NASCAR race to Mars," says Philip Christensen, a
planetary geologist at Arizona State University who is involved with one of the
missions.

First off the pad will be a quirky, budget-built British robot scheduled for
launch tomorrow in Kazakstan. Trailing its fumes will be a pair of NASA rovers
departing separately from Cape Canaveral. Instrument-laden European and Japanese
orbiters are also aiming to converge on the planet early next year.

The timing is no accident. Celestial mechanics are swinging Mars and Earth
within 34.6 million miles of each other, closer than at any time in recorded
history. For Mars-obsessed scientists, it's too good to pass up.

In addition, growing scientific evidence has led to renewed speculation that
Martian soil is not as sterile as it seems.

"Mars is probably the most interesting object in the solar system, and for one
reason: It's the most likely place to find evidence of life," says John Logsdon,
director of the Space Policy Institute at George Washington University.

Of all the spacecraft that will be sailing toward the planet, the one with the
greatest potential for a stunning payoff is Britain's Beagle II. Not since the
Viking landers crunched down on the planet's sandy surface nearly 27 years ago
has a spacecraft been designed to test so directly for signs of extraterrestrial
organisms - dead or alive.

Named after the vessel Charles Darwin used to explore the South Seas, the $60
million lander is scheduled to parachute down Christmas Day. On the ground, it
will unfold four solar panels and a robotic paw that is to serve as a mobile
laboratory. The lander will remain stationary while the paw does the work.

Although far less expensive than Viking, Beagle II's experiments are more
sophisticated, says Raymond Arvidson, a former Viking project scientist now at
Washington University in St. Louis.

Viking's samples from the Martian surface showed dead rock. Only afterward did
scientists realize that ultraviolet rays bombarding the planet could have
destroyed evidence of life on the surface. Beagle II will bore into the soil and
chew up rocks on the surface to retrieve samples unaffected by radiation.

Onboard spectrometers and other instruments will test the samples for chemical
signs of life. One of the most important is the ratio between two isotopes of
carbon, Carbon-12 and Carbon-13. On Earth, a higher concentration of Carbon-12
usually signals the presence of life.

Tantalizing signs

Most scientists think finding evidence of life is a long shot at best, but not
as long as it once was. A pair of NASA orbiters now circling Mars have found
tantalizing signs of frozen water a few feet below the surface in equatorial and
polar regions. Water is one of the most important prerequisites for life - on
Earth, at least.

In addition, scientists have discovered bacteria flourishing in some of the most
inhospitable places on this planet, from hydrothermal vents on the ocean floor
to subterranean rock. That tells them that the harsh conditions on Mars don't
rule out life.

Beagle II, which weighs 73 pounds and is about the size of a backyard grill, is
drawing attention not just for its scientific potential, but also for its quirky
British pedigree.

Britain's most significant venture into space since, as one pundit cheekily put
it, "James Bond went into orbit in Moonraker," the craft was cobbled together
with funding from a variety of sources that included British universities,
private corporations and even the national lottery.

"Imagine the audacity to say the first mission we're going to send anywhere is
to Mars to look for life," says Christensen. "You've really got to give those
guys credit."

NASA's rovers won't be looking for life, but for the water that could support
it. Scheduled for launch June 8 and June 25, the buggies will bounce down to
Mars' surface in cocoons of air bags, much like NASA's last successful Mars
lander, the toy-like Sojourner rover.

Robot geologists

At 400 pounds, the latest vehicles look nothing like their predecessor, and
they're designed to cover as much as 130 feet a day. "We're the monster truck of
Mars rovers," says astronomer Steven Squyres of Cornell University, leader of
the mission's science team.

Squyres, who calls the mission the "most aggressive" Mars junket ever, says the
rovers are designed to act as robotic geologists. Over three months and an area
the size of 10 football fields, they will use a panoramic camera, a microscopic
imager, drill and three spectrometers to search for signs of water.

The first rover is headed toward Gusev Crater, a giant bowl south of the Martian
equator that is thought to possibly be an ancient lake bed. The second buggy
will bounce down at Sinus Meridiani, where NASA orbiters have spotted deposits
of a gray mineral called hematite. On Earth, hematite is often formed in the
presence of water, which makes the site especially tantalizing.

"It's like a chemical beacon visible from space that says: 'Water may have been
here,'" says Squyres.

The British and American spacecraft will be joined by others. Beagle II will
hitch a ride aboard the European Space Agency's Mars Express satellite, which is
also designed to seek out sources of water.

The wayward Japanese orbiter Nozomi, launched in 1998, might also show up.
Designed to study the Martian upper atmosphere, Nozomi was originally supposed
to arrive four years ago. But it blew a thruster en route, so Japanese
controllers parked the spacecraft in a solar orbit until the planets were more
favorably aligned and it wouldn't have so far to travel.

The flotilla will join two NASA spacecraft, Mars Odyssey and Mars Global
Surveyor, which are in orbit studying the planet's atmosphere.

The chances that all of the spacecraft will make the trip are grim. Just 13 of
the 31 probes dispatched to the planet since 1960 have arrived intact. Fewer
still survived long enough to carry out their missions. As a result, the planet
has earned a reputation as the Bermuda Triangle of the solar system.

"It's gobbled up a lot of hardware," Squyres concedes. "But it also tends to
draw more missions because it's such a tasty target."

Copyright © 2003, The Baltimore Sun