By
Richard Stenger
CNN.com Writer
(CNN)
-- After last year's loss of two red planet explorers, NASA
on Thursday unveiled an ambitious plan to send eight or
more probes to Mars over the next two decades to search
for evidence of water or life.
The
fleet of orbiters, landers and rovers would employ new technologies
that expand their scientific capabilities, save fuel and
improve their chances of surviving on the red planet, NASA's
chief Mars mission managers said Thursday.
In addition
to a 2001 orbiter and twin 2003 rovers, all previously announced,
the agency plans to send a more powerful orbiter in 2005,
a long-range mobile laboratory in 2007 and a new line of
"scout" missions that could involve scientific
balloons or miniature landers. The first could arrive as
early as 2007.
The
first mission that returns samples of martian soil or rock
could launch from Earth as soon as 2011, NASA said. The
new, open-ended approach stands in contrast to the specific
agenda outlined in the agency's previous Mars exploration
plan. Agency officials said the new plan represents an adjustment
-- but not an abandonment -- of the "better, faster,
cheaper" approach of recent years.
In 1999,
NASA lost a Mars orbiter and lander, each right before it
was to begin its mission. The first most likely burned in
the atmosphere because managers failed to convert metric
and English measurements. The second presumably crashed
moments before landing because of a software glitch.
The
future orbiters would expand the search for liquid water
on Mars, a strong indicator of possible past or present
life. Scientists looking at high-resolution images taken
by the Mars Global Surveyor announced in June they had identified
visual evidence of water just underneath the surface.
Surveyor
has orbited the red planet since 1997 and can spot features
as small as 3 meters (10 feet). The 2005 orbiter will be
able to discern objects smaller than one foot.
"It
can see things the size of beach balls," Scott Hubbard,
Mars program director, told reporters.
Afterwards,
using intelligence gathered by the satellites, the new generation
of rovers could traverse the surface of Mars for years instead
of months, seeking out possible oases that possess water
and possibly life, Hubbard and colleagues said.
NASA
envisions bold new technologies to ensure the success of
its ambitious plans, expected to cost at least $450 million
annually for the next five years. The sample return mission
could balloon to as much as $2 billion.
The
details on the probes are deliberately left open-ended,
but officials said they could employ smart sensors to find
safe landing sites, airbrake through the atmosphere to save
fuel, use radar to search for underground water, and perhaps
include heavy machinery to bore deep below the surface.
The
missions are part of a long-term Mars exploration program
developed over the past six months. NASA expects to refine
the engineering concepts and costs over the next 18 months.
The
agency said international partners like the French and Italian
space agencies would play an integral role in the missions.
|
