NASA's Phoenix Mars Lander is going
to try something new — pushing aside a Martian rock and peeking at what's
underneath, mission scientists said Monday.
A series of commands just developed
by mission engineers will allow Phoenix's
7.71 foot-long (2.35 meter-long) robotic arm to nudge the rock, located on the
north side of the lander. The arm wasn't actually
designed to make this kind of move.
"We don't know whether we can
do this until we try," said Ashitey Trebi Ollennu, a robotics
engineer at NASA's Jet Propulsion Laboratory, in Pasadena, Calif.
"The idea is to move the rock with minimum disturbance to the surface
beneath it. You have to get under it enough to lift it as you push it and it
doesn't just slip off the scoop."
The Phoenix mission was extended
last week by NASA to run through December. The lander,
which has been on the surface of Mars since May 25, has been examining the
surface layers in the planet's arctic region to assess the potential past
habitability of the area.
If the technique the engineers have
developed works, enough area will be exposed for Phoenix to dig into the dirt that now lies
beneath the rock. The rock is about the side and shape of a VHS cassette and is
informally named Headless.
"The appeal of studying what's
underneath is so strong we have to give this a try," said Michael Mellon,
a Phoenix science team member at the University of Colorado
at Boulder.
Digging into the dirt under the rock
could shed light on the processes that affect the hard, icy layer found beneath
the Martian surface in trenches that the robotic arm has dug around the lander.
"The rocks are darker than the
material around them, and they hold heat," Mellon said. "In theory,
the ice table should deflect downward under each rock. If we checked and saw
this deflection, that would be evidence the ice is
probably in equilibrium with the water vapor in the atmosphere."
Alternatively, if the icy layer were
found closer to the surface under the rock, it could suggest that rocks collect
moisture from the atmosphere, with the moisture becoming part of the icy layer.
Commands to move the rock were sent
to Phoenix on Sunday evening so that Phoenix could perform the
action on Monday. Over the weekend, Phoenix
enlarged a trench close to Headless and took a pair of images
of Headless with its stereo camera to provide a detailed 3-D map for
planning the arms' movements.
advertisement
