(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.
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| Illustration of the Mars 2007 "smart lander" |
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.
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