Hear the Sound of Philae's Historic Landing

You want to hear what a historic moment sounds like? Philae and the German Aerospace Center (Deutsches Zentrum für Luft-und Raumfahrt; DLR) can provide.

That crunchy thud you heard is the sound Philae made when it first made contact with the surface of the comet 67P/Churyumov-Gerasimenko, making history as the first manmade craft to make a soft landing on a comet as it hurtles through our solar system.

Of course, it was later revealed that that "soft landing" was more like a jarring pair of bounces until Philae settled in an unexpectedly dark and uncharted part of the comet, but if anything, that just gave us a more discernible sound for the lander's Cometary Acoustic Surface Sounding Experiment (CASSE) instrument to record.

And if you're wondering how any sound at all was made in the vacuum of space, it should be pointed out that this recording does not come from the exterior of Philae, but from within its closed and pressurized instrument chambers - where molecules can still vibrate to make sound waves.

It's also important to note that the CASSE was designed to measure the sound of Philae's landing legs as they touched down, providing clues to what the surface of the comet is like.

"The Philae lander came into contact with a soft layer several centimetres thick. Then, just milliseconds later, the feet encountered a hard, perhaps icy layer on 67P/Churyumov-Gerasimenko," DLR researcher Klaus Seidensticker, who is responsible for the Surface Electric Sounding and Acoustic Monitoring Experiment (SESAME), which includes CASSE, explained in a statement. (Scroll to read on...)

He added that this brief recording also helped the Philae team understand that the initial landing didn't go as intended, as no sound persisted after first contact.

"From our data, we can determine that no second landing occurred immediately after the first bounce," added Martin Knapmeyer, leader of the CASSE Team.

After the first bounce, the European Space Agency and Philae team determined that the lander effortlessly glided over the comet for nearly two hours, rendering the audio sensors quiet. The Lander finally bounced once more and came to stop more than 3,300 feet away from the predetermined Agilkia landing site. As things stand, the lander is currently trying to collect solar power to continue operations.