The sound of Rosetta

Philae sole of foot +X with CASSE accelerometer during integration

ESA's Rosetta mission is on its way to its target comet, 67P/Churyumov-Gerasimenko since 2004. The Comet Lander, Philae, built under DLR lead, is operated from the DLR Lander Contol Center (LCC) in Cologne.

CASSE: Time series (spinning-up)

During several flight events in 2009 and 2010 the Lander team has been asked by ESA to help with the characterisation of a Rosetta reaction wheel, which was relubricated in flight. The piezoelectric CASSE (Comet Acoustic Surface Sounding Experiment) sensors (integrated in the Lander's "feet soles") could listen to the microvibrations caused by the reaction wheels and transmitted via the structure.

Scientists at MUSC have translated these (acceleration) curves into audiofiles: at the real sampling frequency of 1220 Hz you can hear a sonorous hum, while in the 7-times accelerated playback of the audiofiles the changes in rotation speed are well audible.

CASSE: Time series (spinning-down)

Contact

Dr.rer.nat. Jens Biele
MUSC
German Aerospace Center
Space Operations and Astronaut Training
Köln-Porz
Tel.: +49 2203 601-4563
Fax: +49 2203 61471

Dr.rer.nat. Hans-Herbert Fischer
MUSC
German Aerospace Center
Space Operations and Astronaut Training
Köln-Porz
Tel.: +49 2203 601-4566
Fax: +49 2203 61471

original speed (27.10.2009 start 16:30:02.3124 UTC)

Time series of channel +Xy during spinning-up of RW B from 1000 to 2000 RPM; simultaneously, rapid changes of the speeds of RW A, C, D took place. (0.28 MB)

7 times original speed (0.28 MB)

original speed (27.10.2009 start 19:00:02.0047 UTC)

Time series of channel +Xy during spinning-down of RW B from 2000 to 1500 rpm; simultaneously, changes of the speeds of RW A (2300 to 1800), C, D (2800 to 2300 rpm) took place. (0.28 MB)

7 times original speed (0.28 MB)

CASSE - Cometary Acoustic Surface Sounding Experiment