Mars Lander set for soft touchdown
Thursday, August 26, 1999 Published at 04:15 GMT 05:15 UK
Nasa
scientists say they have a found a landing site on Mars for the Polar Lander probe to
touch down on the Red Planet later this year. The probe, designed to search for water in
the form of ice or vapour on the Martian surface, will come down softly on the fine dust
of "gentle, rolling plains" in a target area 198km (124 miles) long by 19km
(12.4 miles) wide near the planet's south pole.
![[ image: The Lander carries equipment to test soil samples for traces of water]](_247681_landergph150.jpg) |
| The Lander carries equipment to test soil samples for
traces of water |
Scientists know water once flowed freely on Mars - this mission's objective is
to find out what happened to it.
The probe also carries a microphone, which for the first time will allow
scientists to hear sounds from the surface of another planet.
The Lander is due to touch down on 3 December at the site 76 degrees latitude
south and 195 degrees longitude west. A backup site is located nearby.
(Click here to
see a Nasa photograph of the landing site)
As the probe arrives, the planet's southern hemisphere will be approaching the
beginning of its summer, allowing the spacecraft's solar panels to function throughout the
day.
![[ image: The landing site is expected to be different from the rocky surface encountered by Pathfinder]](_430442_pathfinder150.jpg) |
| The landing site is expected to be different from the rocky
surface encountered by Pathfinder |
"We chose a location with some surface features, but no cliffs or jagged
peaks, because the spacecraft will be able to land safely, yet we'll still accomplish our
science goals," said Project Scientist Dr Richard Zurek, of Nasa's Jet Propulsion
Laboratory in Pasadena, California.
He said the site, about 800km (400 miles) from the pole itself, appears to have
layers of dust and ice that will provide a record of the Martian climate much like reading
tree rings.
"In addition, we may find evidence of soil particles that formed in ancient
seas on Mars and were later blown into the polar regions."
Mars surveyor
The site is expected to be very different from the rocky surface pictured by the
earlier Pathfinder and Viking landers.
The site was chosen by scientists examining data sent back by the Mars Global
Surveyor which is currently orbiting the planet.
That probe has already revealed some astonishing features of the planet,
including a crater so deep it could swallow Mount Everest, and another that has been
nicknamed the Happy Face Crater because of markings similar in appearance to a simple,
smiling human face.
Launched on 3 January this year, the Polar Lander also carries with it two
"microprobes" known as Deep Space 2.
 |
| Mars' "Happy Fcae Crater" pictured from the Mars
Global Surveyor |
They will launch from the main craft about five minutes before it enters the
planet's atmosphere, then smash into the surface to study the Martian soil from beneath
its top layer.
The Mars Polar Lander forms the third phase of Nasa's long-term programme for
the robotic exploration of Mars.
The programme began with the groundbreaking Pathfinder mission in 1996, which
sent back vivid pictures of the planet's barren surface.
Then came Mars Global Surveyor which began to map the planet from orbit.
Scientists hope that additional missions planned every two years will lead to a
manned voyage to Mars as early as 2015.
![[ image: The purple elipse shows the primary landing site, the backup is shown in white. Photo: NASA/JPL/Caltech ex mission website]](_430442_landsite300.jpg) |
| The purple elipse shows the primary landing site, the
backup is shown in white. Photo: NASA/JPL/Caltech ex mission website |
