Mars Polar Lander Science to Begin Dec. 3
News Services
University of Arizona
Contact:
Lori Stiles, UA News Services, 520-626-4402
Days from now, scientists will witness their experiments complete an
11-month, 137-million-mile space trip to Mars.
On Friday, Dec. 3, NASA’s Mars Polar Lander is to make a first-ever landing
near a pole of the Red Planet, the south pole. Landing begins the first martian
day of the 3-month mission, or “sol 0.”
The spacecraft carries a science payload package called MVACS, or the Mars
Volatiles and Climate Surveyor. MVACS is to search for water and other gases
that once filled a thick martian atmosphere. Scientists have convincing
evidence that sometime in Mars’ geological past, liquid water catastrophically
flooded the planet.
But today, the martian atmosphere is so thin that if temperatures were to
reach above freezing, water would instantly boil away. What caused the
climate to drastically change, and what happened to the atmospheric gases, the
water and carbon dioxide — the “volatiles”?
Past atmospheric gases may be locked as ice, salt and other compounds in the
soil. MVACS scientists will dig for the answers. Their research tools were
designed and built at the University of Arizona by Lunar and Planetary
Laboratory (LPL) researchers, students and international colleagues.
Soon after landing, a UA-built multi-spectral, stereoscopic camera called
Surface Stereo Imager (SSI) will begin its photographic survey of the landing
site.
Peter H. Smith of LPL heads the group who built SSI. This camera is identical
to the Pathfinder camera that landed on Mars on July 4, 1997 and took more
than 16,500 images for what is widely regarded as one of the most successful
and publicly popular missions in NASA history. Smith is sure to be a
participant in some of the first news briefings from the NASA Jet Propulsion
Laboratory (JPL) in Pasadena, which is managing the mission.
According to current plans, which are subject to change, payload commanders
will flex a six-foot, six-inch robotic digging arm on sol 4 or sol 5 (Dec. 7 or
8). A sol, or day on Mars, is 24 hours and 37 minutes.
Smith, his team and colleagues at Germany’s Max Planck Institute for
Aeronomy designed and built RAC, or the Robotic Arm Camera, on the wrist of
the robotic arm. It will take close-up views of the icy martian terrain. This
camera is able to resolve an image of a single human hair from a distance of
half an inch. Researchers will see detail in good-sized chunks of gravel down
to fine grains of sand. RAC will inspect trench walls as the robotic arm digs.
Lamps mounted on this camera shine in red, blue and green from several
directions. Without the colored lights, the scientists would see only
black-and-white images. With them, they will see color as well as structure
of the soil.
While the 1997 Mars Pathfinder camera cost $5 million, SSI and RAC
together were built for $2.7 million. They and the JPL-built robotic arm are
integral to TEGA, the Thermal and Evolved Gas Analyzer investigation headed
by William V. Boynton.
Boynton, UA professor of planetary sciences, originally conceived the idea for
the TEGA 16 years ago, while thinking about ways to measure ices in a comet.
It features the tiniest out-of-this world ovens that ever cooked alien soil.
On sol 5 (Dec. 8) or after, the robotic arm will begin scooping samples of
frozen dirt into TEGA so scientists can learn how much water and carbon
dioxide are locked in the layered polar terrain. TEGA will use electric current
to heat soil samples collected by the robotic arm scoop.
The instrument has eight analyzers, each holding two ceramic ovens, each
about the size of a piece of macaroni. One oven in each analyzer remains
empty, the other will hold a thousandth of an ounce (about 30 milligrams) of
Mars soil. The ovens heat at a controlled rate of a few degrees per minute up to
1,000 degrees Celsius. The ovens leak heat; they are not perfectly insulated.
By measuring heat loss in the empty oven and subtracting that amount from
the heat in the filled oven, researchers will know exactly how much energy
the soil samples absorb. A carrier gas wafts gases released during heating into
a chamber that uses lasers to analyze amounts of water and carbon dioxide.
The $4.4 million TEGA project is rare in university history because it was
designed from scratch, assembled and tested entirely at the UA, without a
space industry firm as major contractor. In three years, university
engineers and scientists took TEGA from concept to
blueprint to flight-ready science instrument with near-microscopic, delicate
parts able to survive the force of 70Gs at launch (force 70 times that of
Earth’s gravity.) “We all gave three and a half years of our lives to the three
year project,” said senior LPL engineer Mike Williams.
Smith and Boynton say their teams faced formidable technical
challenges, stringent budget cost-caps and nail-biting deadlines. Soon after
Jan. 3 Mars Polar Lander launch, project staff accelerated into a hectic
schedule of instrument systems testing and team training.
Months prior landing, MVACS team members held round-the-clock
operational readiness tests at the UCLA Science and Technology
Research Building. This building also will be their science operations center
during the mission. David Paige of the University of California Los Angeles is
principal investigator for MVACS.
The planetary scientists know space exploration is risky business. But to hear
them talk, the risk is no match for possible rewards.
“Today is the Renaissance for planetary science, just as the age of da Vinci and
Titian was a Renaissance for art a few hundred years ago,” Smith said. “Many
questions (in planetary science) are being answered for the first time now,
and we are lucky enough to be alive during this time. For me, it’s
tremendously exciting.”
Boynton said, “For me, the most exciting (new discovery) is that Mars was
very, very wet in the past, because everything we know about life says that
water is an essential part of it. If Mars was always as dry as it appears now to
be, then it’s not very likely life could have ever gotten started. But if there
really were oceans on Mars at one time, that’s exciting. If life didn’t get
started there, we’d really have to wonder why not.”
“There are not many places in the country where students have the
opportunity to participate in exciting space missions like this one,” Boynton
said. “The students who have worked with us have learned an awful lot. And I
think as far as NASA is concerned — as far as the country is concerned, for
that matter — educating students is probably the most important part of the
space program. They will be the people we rely on for the next generation of
technology that’s going to keep our economy going.”
The UA camera team will post new images from Mars at the Mars
Atmospheric and Geologic Imaging website,
http://imp.lpl.arizona.edu/mvacs
The TEGA team will post their data at the TEGA web page,
http://grs8.lpl.arizona.edu/tega/
and at the Boynton Group website,
http://nemesis.lpl.arizona.edu/
For more information on Mars Polar Lander, click on the JPL Mars Polar
Lander web page,
http://mars.jpl.nasa.gov/msp98/
or Exploring Mars,
