In Search for Life on Mars, Machines Can Boldly Go
Where Humans Can't
LAWRENCE M. KRAUSS
dwindling hope, scientists with the European Space Agency have awaited
a nine-note musical message, much like the sound I hear on my
daughter's cellphone when it receives a call.
Hearing this tune, written by a British band, Blur,
would signal that
the British-built Beagle 2 spacecraft landed safely on Mars two weeks
ago and could begin experiments to detect trace signatures of past or
present microbial life.
Whether or not the tiny Beagle 2 survived its dangerous
descent to the
Martian surface, the Spirit, a robotic craft launched by NASA, landed
safely on the planet over the weekend and began transmitting
photographs of the surface within hours. A sister NASA rover, the
Opportunity, will try to land this month.
The rovers are to travel several hundred feet a day in
search of evidence that liquid water once flowed on Mars.
Humanity has been fascinated by the possibility that
life may have
existed on Mars, our closest planetary neighbor, for as long as
telescopes have allowed us to peer at its red surface. At the end of
the 19th century, the American astronomer Percival Lowell detected what
he was certain were "canals" on Mars that reflected an advanced
While we now know that this was merely an optical
illusion because of
the limited resolution of the available observation instruments,
Lowell's statements prompted generations of books and movies
speculating on Martian invasions of Earth.
The fascination with the possibility that life once
existed on Mars is not restricted to literature and the movies.
Scientists recognize that the climate of the barren
planet was once
quite different, with a denser, warmer atmosphere, as well as the
possibility that liquid water may have flowed on its surface. Seven
years ago, analysis of a Martian meteorite found in Antarctica set
scientists abuzz with the claimed discovery of fossilized evidence of
microscopic life forms.
Although most scientists now view that evidence as
suspect, the idea
that some ancient life may have existed on Mars remains plausible.
Indeed, given that the Martian rock being analyzed was found on Earth
makes it clear that material is regularly exchanged between the
planets. For all we know, life on one planet may have "seeded" life on
another at some time.
In spite of the tantalizing idea that life might be
found on Mars,
mounting a successful mission there to resolve this mystery is not so
easy. Of the 11 attempted landings on Mars, only 4 have been successful
up to now.
Space travel remains a difficult and expensive activity.
excitement surrounding the current European and American landings makes
it clear that the scientific questions that they may answer inspire a
host of people. The activity also makes clear a fact that most
scientists keep trying to underscore, that the best, most exciting and
cheapest science involves unmanned spacecraft.
Even after only a 35 percent success rate thus far, the
11 missions to
Mars have in total cost probably less than 1 percent of the projected
cost of sending astronauts to Mars. Moreover, a lost robotic spacecraft
is replaceable. An astronaut isn't.
As President Bush and NASA try to re-examine how to
America's manned-space program, now is the time to face up to various
truths about human space travel from scientific and human perspectives.
First, basically all that we learn from sending humans
into space is
how humans can survive in space. The International Space Station,
orbiting several hundred miles above Earth, is not only boring, but it
is also expensive.
Pretending that it has a scientific objective of any
significance is an
insult to those aspects of NASA, including the Great Observatory
programs, and the new rover landings, that promise real science.
If we are going to send human beings into space, we must
we are doing it primarily for adventure and to fulfill a human yearning
to directly explore where "no one has gone before."
There is nothing wrong with adventure. At the very
least, in inspires
young people to think about the cosmos, much as the Apollo missions
fascinated and excited my own interest in science 30 years ago. But to
keep our space program vibrant, we need to ensure that we supplement
expensive human space missions with important, and cheaper, scientific
ones like the three current Mars missions.
Perhaps one day humans will visit, and even colonize,
this is our destiny. But for now, two — and maybe three — small robotic
messengers are poised to help answer one of the most profound questions
in science. Is there life, even primitive life, elsewhere in the
I am rooting for one of the tiny spacecraft now lying
alone on the
inhospitable Martian soil, hopefully sending out messages to Earth,
almost 100 million miles away, and I will not be disappointed if the
first encounter with evidence of life elsewhere is made by a machine.
Lawrence M. Krauss, chairman of the physics
Case Western Reserve University, recently testified before Congress on
the future of space exploration.