NASA
scientists hope to hear what it sounds like on the surface of Mars for the
first time when they attempt to switch on the Phoenix Mars Lander's microphone
in the next week or two, mission leaders announced on Monday.
"This
is definitely a first," said Phoenix
principal investigator Peter Smith, of the University of Arizona, Tucson.
Phoenix's microphone is a part of the Mars
Descent Imager system that was included on the underside of the lander to take
downward-looking images during the three minutes of descent before the
spacecraft touched down on the planet's surface. The MARDI on Phoenix was
originally designed for the Mars Surveyor 2001 Lander missions, which were
eventually canceled. The system is also similar to the one aboard 1999's
ill-fated Mars Polar Lander.
The plan to
use the imager and microphone on May 25 (when Phoenix
landed) were scrapped when tests showed that using the system would create
an unacceptable risk to a safe landing for Phoenix.
Phoenix did safely land at its appointed
side in the Martian arctic, where it has been digging up samples of dirt and
subsurface water ice and analyzing them with its instruments to assess the
planet's past
potential habitability.
Though the
original plan to use Phoenix's mike during landing was scrapped, mission
scientists didn't rule out using it later during the mission.
"We'd
always hoped to turn it on," Smith said.
The team
needed NASA's approval for funding to turn on the microphone, and now they've
gotten the go-ahead, Smith said.
They can't
flip the switch right away — there are still a few checks that need to be done,
and Phoenix's software needs to be changed a bit, Smith told SPACE.com.
"We're
just kind of cranking it up," he said.
Martian
sounds
Once all
the preparations are ready, the team plans to try to turn the microphone on
while the lander is digging or using
the rasp on the end of its robotic arm scoop, "just to make sure we
hear something," Smith said. "You at least want to know if there's a
chance of noise being created."
Phoenix scientists aren't sure just what,
or how much, they'll hear. For one thing, Phoenix's mike is "not a
professional microphone," Smith said (he likened it to the microphones
used on a standard cell phone).
For
another, sound waves don't
travel as far on Mars as they do on Earth because Mars' atmosphere is
thinner. It would be similar to listening to sound at an altitude of about
100,000 feet (30,500 meters) above Earth's surface, Smith said.
If the team
can hear Phoenix's operations, they'll then turn the microphone on while Phoenix is quiet and just see what they can hear. What that might be, Smith isn't certain.
Potential
images
In addition
to potentially hearing Martian sounds, the Descent Imager system will take a
picture once it's switched on, Smith said.
One
potential photographic subject is the Holy
Cow ice feature directly underneath the lander. The ice was exposed when Phoenix's thrusters pushed away the dirt lying on top of it during landing. The feature
was first imaged by Phoenix's robotic arm camera.
The imager
might also catch a glimpse of some so-called "barnacles" attached to Phoenix's legs. Smith describes these as "bright dots on the legs" that are
pieces of the Martian surface that were splashed onto the legs by the thrusters
during landing.
Some of the
dots have grown and some have moved around over the course of the mission,
which is now entering its fifth month on the Martian surface. Mission
scientists aren't sure why the dots have such unusual behavior.
"It's
one of those wonderful Martian mysteries," Smith said.
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