Phoenix Lander Will Listen to the Sounds of Mars

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We may be able to hear, for the first time, what it sounds like on the surface of Mars. The Phoenix Lander has a microphone on board, which will be switched on in upcoming days of operations. “This is definitely a first,” said Phoenix principal investigator Peter Smith. The microphone is a part of the Mars Descent Imager (MARDI) system on the underside of the lander designed to take images of Mars’ surface during the lander’s descent. However, the system was never used. Tests of the system during the flight to Mars revealed the possibility that using it might cause other parts of the landing system to not function correctly. But using it later wasn’t ruled out. So, after updated software is sent to the lander, the microphone will be turned on.

You may recall, Mars Express recorded the sounds of Phoenix descending (which sounded like Phoenix was screaming in delight!) But now we may be able to hear the sounds of Mars itself – a truly wondrous possibility.

There’s no guarantee the microphone will work, however. Once the system is checked and updated, the team plans to attempt turning the microphone on while the lander is digging or using the rasp on 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.”

No one knows what Mars sounds like, and Phoenix scientists aren’t sure how well the microphone will be able to pick up any noise. Smith said the microphone is similar to what is used on a standard cell phone. Also, sound waves don’t travel on Mars as they do Earth because of Mars’ thin atmosphere. It would be similar to listening to sound at an altitude of about 30,500 meters (100,000 feet) above Earth’s surface, Smith said.

If the team can hear Phoenix’s operations, then they’ll turn the microphone on while Phoenix is quiet and wait for any sounds.

Additionally, the descent imager might be turned on, as well. This provides the opportunity to take close up images directly underneath the lander, where the “Holy Cow” feature – which appears to be a large chunk of ice – is located.

The imager might also be able to look at the clumps of materials that appear to be “growing” on Phoenix’s legs. The clumps are probably bits of Mars soil that “splashed” up on the legs during landing, but some of the clumps have moved around and appear to be increasing in size over the duration of the mission. Mission scientists aren’t sure what the clumps are and why they have such unusual behavior.

“It’s one of those wonderful Martian mysteries,” Smith said.

Post Script & Corrections: Thanks to Emily Lakdawalla of the Planetary Society for providing the correct image and information of the MARDI! The first image I had posted was of the Mars Microphone that the Planetary Society sent along with the Mars Polar Lander mission in 1999. Also, I incorrectly stated that the MARDI instrument was the same as the Mars Microphone on the MPL.

Sources: Planetary Blog, Space.com