Overview: The quest for water

This animation shows have Mars' surface water may have dissipated over billions of years. (Hit reload to replay animation)

November 29, 1999
Web posted at: 11:19 a.m. EST (1619 GMT)

By Amanda Barnett
CNN Interactive Staff Writer

In this story: Where did all the water go? Measuring and cooking Martian soil Hearing red Sister ship was lost RELATED STORIES, SITES

(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.

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Destination Mars

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.

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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.

Artist's conception of the Polar Lander on the martian surface.

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.

The Associated Press contributed to this report.