Audio Clip Shows What Landing On A Comet Sounds Like

Chuck Bednar for redOrbit.com – Your Universe Online
It might just be a two second clip of what sounds like some rustling paper or a dull thud, but the recording of the Philae lander’s touchdown on Comet 67P/Churyumov-Gerasimenko (67P/C-G) released by the German Aerospace Center (DLR) on Thursday allows astronomy enthusiasts to hear just what making history sounds like.
The brief sound bite was captured by the Cometary Acoustic Surface Sounding Experiment (CASSE) instrument sensors, which are located in the feet at the base of the Philae’s three legs, DLR officials explained in a statement. The sensors were active as the lander made its historic first touchdown on November 12, the agency added.

While CNET’s Eric Mack admits that the recording “may not sound like much,” he emphasizes there is “a lot in the two-second recording for scientists to digest.” For instance, DLR scientists said that the Philae probe made initial contact with a soft layer several centimeters thick, then milliseconds later, it encountered a hard, possibly icy part of the comet’s surface.
According to DLR, CASSE first detected vibrations from the flywheel used to stabilize the flight. Upon its first contact with the comet’s surface, the lander rebounded off of the surface because the harpoons designed to anchor it as it touched down failed to deploy. Scientists from the German space agency said that, based on their data, Philae did not immediately return to the comet after it bounced off 67P/C-G’s surface.
Philae landed a total of three times, and after it finally came to rest, it immediately began making scientific measurements. Afterwards, CASSE transmitted and received vibrations from the lander’s feet in order to determine the properties of the comet’s surface, and was also able to detect vibrations as the Multi-Purpose Sensors for Surface and Subsurface Science (MUPUS) tool attempted to hammer a probe into the ground.
While Rachel Feltman of The Washington Post noted that data regarding the second post-bounce landing only confirmed what mission scientists already knew, Philae project scientist Klaus Seidensticker said that he and his DLR colleagues were initially worried their instruments would be unable to collect any data from the comet. Now, however, he said they have “much more data than I had hoped for.”
Rosetta begins science phase
Meanwhile, in related news, ESA announced that the Rosetta orbiter had continued into its own full-science phase now that Philae’s part of the mission has come to a close. This week, the spacecraft has performed a series of maneuvers, using its thrusters to optimize its orbit around 67P/C-G for its 11 onboard scientific instruments, the agency noted.
Additional burns were planned for Wednesday, November 22 and November 26 in order to further adjust the orbit to bring it to approximately 30 kilometers above the comet, explained Spacecraft Operations Manager Sylvain Lodiot. Starting next week, Rosetta’s orbit will be altered based on the needs of the scientific sensors, and on December 3, it will move down to a height of 20 km for about 10 days, after which time it will return to 30 km.
“The desire is to place the spacecraft as close as feasible to the comet before the activity becomes too high to maintain closed orbits,” said Laurence O’Rourke of the Rosetta Science Operations Centre near Madrid, Spain. “This 20 km orbit will be used by the science teams to map large parts of the nucleus at high resolution and to collect gas, dust and plasma at increasing activity.”
“Science will now take front seat in this great mission. It’s why we are there in the first place!” added Rosetta Project Scientist Matt Taylor. “The science teams have been working intensively over the last number of years with the science operations centre to prepare the dual planning for this phase.”
Rosetta, which launched in March 2004 and spent a total of 957 days in a hibernation-like state while traveling through space before being reactivated, is scheduled to spend the next several months analyzing the comet. It will maintain orbit around the comet through the end of 2015, performing ongoing analysis of the comet as it approaches the sun and then moves further out into deep space.
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