Nasa animation of Mars before with
water and now without
(CNN) -- NASA is about to land on Mars again. The Mars Polar Lander,
a
1,270 pound (576 kg) robotic spacecraft, is scheduled to parachute
through
the thin, cold Martian atmosphere at 3:30 p.m. ET on December 3.
The spider-like craft will fire retro-rockets and make a soft landing on
the
layered terrain at the edge of Mars' south polar cap, a region that may
hold
clues about what happened to the water believed to have flowed long ago
on Mars.
"Water is, to the best of our knowledge, the key building block of life,"
said
Eric Hayne, a spokesperson for NASA's Jet Propulsion Lab in Pasadena,
California. "If we can find it on Mars, it would help us glue together
the
geologic history of Mars and help us find out if there ever was life on
Mars."
So far, none of the spacecraft that has landed on Mars has found any trace
of water. But finding water is critical to future exploration of Mars and
other
planets.
"Wherever we can find water we can produce oxygen, fuel and drinking
water," Hayne said. That means future spacecraft would not have to carry
water from Earth.
Where did all the water go?
Scientists believe water used to be abundant on Mars. Pictures taken by
earlier probes appear to show deep channels, canyons and possibly ancient
lake shorelines -- all features formed on Earth by flowing water.
But where did it go? Some scientists think it was lost to space as the
planet's
atmosphere thinned. Water also may be trapped under the surface. Water
ice has been detected at the Martian north pole and may exist in the cap
at
the south pole.
The lander, launched January 3 from Cape Canaveral, Florida, will set down
in the area where the south pole's layered terrain extends the farthest
north.
Scientists picked this landing site to avoid the region's seasonal carbon
dioxide frost.
Images sent back in 1997 by the currently orbiting Mars Global Surveyor
reveal the layered terrain in the area has a range of contrasts. Bright
areas
are believed to contain surface ice. Darker areas may be partially frosted.
"We think this is a very likely place for water," Hayne said.
Scientists say that like the rings on trees, the bands may help solve a
big
martian mystery: Was the planet's climate change catastrophic, or gradual?
Measuring, cooking Martian soil
The lander's science payload includes the Mars Volatiles and Climate
Surveyor (MVACS), the Mars Descent Imager (MARDI) and a Light
Detection and Ranging (LIDAR) instrument.
The MVACS package will study
water and carbon dioxide at the
landing site. The lander doesn't have a
rover like the Mars Pathfinder which
stopped transmitting in September of
1997. Instead, the lander's
6-and-a-half foot (2 meter) robotic
arm will dig into the soil and the
geologic history of Mars.
It will scoop up soil samples to be tested by other instruments on the
probe.
One instrument, the thermal and evolved gas analyzer, will be used to heat
soil samples and analyze them for water and carbon dioxide.
A sophisticated digital camera will pop up from the lander's deck. It has
two
lenses that will snap 3-D panoramic color pictures around the landing site.
It's identical to the imager used in 1996 on the Pathfinder lander.
The arm also is equipped with a camera for close-ups of the soil.
The MVACS package includes a weather station to measure wind speed,
temperature and water vapor.
MARDI is the camera that will take about a dozen black and white pictures
as the lander descends to the surface.
LIDAR is provided by the Russian Academy of Science's Space Research
Institute. It's the first Russian experiment to be flown on a U.S. planetary
spacecraft. It will help scientists learn more about ice and dust in the
lower
part of the Martian atmosphere.
The Mars Lander also is carrying two basketball-sized probes called Deep
Space 2. About 10 minutes before touchdown, as the lander plummets
toward the planet's surface, the probes will be released. They should dig
about 3 feet (1 meter) into the ground to help in the search for water.
Hearing red
What does Mars sound like? The lander will let Earthlings listen to the
Red
Planet through an instrument the size of a pack of Post-it notes that weighs
less than 2 ounces (57 grams).
Appropriately, given the low-tech name "Mars Microphone," the device
uses a $15 microphone connected to a chip commonly found in telephones
and talking toys.
Unlike other instruments aboard the $165 million spacecraft, the Mars
Microphone is privately funded and has no clear scientific mission.
The sounds will be posted on the Planetary Society's Web site at
www.planetary.org. They also will be available on CNN.com, NASA, and
other Web sites.
The late planetary scientist Carl Sagan first proposed wiring a lander
for
sound during the Viking missions to Mars in the 1970s, but the idea didn't
catch on because scientists believed other instruments could provide more
valuable data.
Sister ship was lost
The Mars Lander's sister ship, the $125-million Mars Climate Orbiter, was
lost as it entered the orbit of Mars in September. Mission managers blame
a
math problem.
While JPL engineers assumed they were using metric measurements
(newtons), engineers at Lockheed Martin Astronautics in Denver, the prime
contractor for the mission, were using English units (pounds) to measure
the
strength of thruster firings.
Engineers say the problem has been corrected for the Mars Polar Lander.
NASA expects the lander to operate 60 to 90 Martian days or Sols. A Sol
lasts about 24 hours, 37 minutes. If the lander continues to operate well,
the
mission may be extended.