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Online NewsHour Special Reports:
Mars Polar Lander
One Giant Leap multimedia
Aug. 26, 1999:
Chandra Observatory, has relayed spectacular images
of exploding stars to NASA
July 20, 1999:
The 30th anniversary of Neil
Armstrong's first steps on the moon.
Dec. 8, 1998:
An Online Q and A: The
International Space Station
Nov. 20, 1998:
Russians send the first component of the International
Space Station into orbit.
March 6, 1998:
NASA scientist Alan
Binder discusses the new discovery of water on the moon.
Feb. 27, 1998:
Is the universe
evolving more rapidly now than it has in the past?
Dec. 31, 1997:
The
Hubble Telescope's clear images reach Earth.
Oct. 15, 1997:
NASA
begins its seven year mission to explore Saturn.
Oct. 2, 1997:
Forty years after Sputnik
first circled the Earth, historians examine its impact.
Sept. 30, 1997:
An
interview with Mir
astronauts.
Browse the NewsHour's coverage of Science
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Hitching a ride on the Polar Lander
are two highly advanced probes called microlanders. The microlanders
are part of the Deep Space 2 mission and are capable of penetrating
below a planet's surface. The main purpose of the miniature probes is
technical, not scientific. NASA is using the probes as a test study
for future planetary surface probes.
Approximately 10 minutes before arrival to Mars, the Polar Lander will
release the probes in a protective covering called aeroshell. The microlanders
are the first objects to land on another planet with only an aeroshell.
Most spacecraft use a parachute and rockets to slow the rate of descent
and land safely on the planet's surface. By eliminating the other materials,
the probes are lighter, less expensive, and they will fall faster.
 The
basketball-sized shells weighing little more than five pounds each will
plummet through the atmosphere and penetrate the planet's surface at
more than 400mph. The probes are designed to endure impact forces up
to 60,000 times the force of Earth's gravity and to operate successfully
in extremely low temperatures.
The probes, roughly the size of a grapefruits, are expected to impact
the surface less than a mile apart. Upon which the aeroshell will shatter.
Each probe will separate into two parts. The lower half of the probe,
called the forebody, will penetrate the surface of the Martian planet
and test soil that was on the Martian surface 100,000 years ago.
 The
forebody will use a micro drill to collect a soil sample. The sample
will be heated and any ice trapped in the soil will be turned into water
vapor. A laser will be shot through the sample and a detector will measure
whether any of the light is absorbed. Missing light indicates the presence
of water vapor.
The data from the forebody will be sent through a flexible cable to
the upper part of the probe, called the aftbody. The aftbody of the
probe remains at surface level during the mission, transmitting information
to the Mars Global Surveyor spacecraft. The Mars Global Surveyor, which
has been in orbit mapping the planet since September 1997, will then
relay the data back to Earth.
The probe life span is only 1 to 2 days. If water is detected, more
probe lander missions will be scheduled. The presence of subsurface
ice does not immediately mean that there is life on Mars, only that
water, an element needed for life as we know it, is present.
The probes are named Scott and Amundsen in honor of the first explores
to reach Earth's South Pole.
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