What will the whoosh of the wind or crack of thunder sound like from a billion miles away? We may now have the answer with the sounds recorded by the Huygens space probe as it descended to Saturn's moon Titan early this morning.
The Planetary Society is teaming with the European Space Agency and the Huygens Atmospheric Structure Instrument team to release the sounds recorded by the Huygens probe. Initial sounds are now available at http://planetary.org/sounds/.
The Huygens Atmospheric Structure Instrument - HASI for short - was designed to explore the temperature, pressure, density, and other physical properties of Titan's sky. Its acoustic sensor, or microphone, listened to the probe's entire descent.
"Wow! What an experience to listen to sounds of an alien world a billion miles away," said Planetary Society Director of Projects, Bruce Betts. "The HASI team, and the entire Cassini-Huygens team, have struck gold with this mission."
Because the Huygens probe was only expected to live about two and a half hours from the time it hit the top of Titan's atmosphere (though data indicate it lived much longer), all the information collected has been transmitted live to Cassini. That means that data was limited since Huygens' instruments are competing for bandwidth. To help process this sparse data into recognizable sounds, the Society worked with Greg Delory of the University of California, Berkeley, who headed the team that built The Planetary Society's Mars Microphone, which flew on NASA's failed Mars Polar Lander spacecraft in 1999.
Marcello Fulchignoni of the University of Paris, heads the international team that designed and built the HASI instrument, on behalf of the Italian Space Agency. The acoustic sensor is part of the Permittivity, Wave and Altimetry subsystem (PWA) and was designed, developed and tested by the Institut für Weltraumfornhung/ÖAW (IWF), Graz, Austria.
"We decided to devote part of our limited data bandwidth to record sounds from Titan," said HASI Principal Investigator Marcello Fulchignoni. "We hope to give the impression of being there."
During Huygens' descent, the HASI acoustic sensor recorded the average power across different sound frequencies every two seconds. This is enough information for the HASI team to determine whether they have detected thunder, but it is not the same as recorded sound. The sounds posted on The Planetary Society's website are more similar to the noises one would actually have heard during the probe's descent if riding aboard it. Those sounds still need to be analyzed further by the HASI team, but could include the rush of the atmosphere, wind, thunder from local storms, the deployment of the probe's braking parachutes, and even the noise of Huygens' impact on the surface.
The Planetary Society congratulates all those involved with Cassini-Huygens including ESA, NASA, and the project teams, on this unique and spectacular accomplishment.
"The successful entry, descent and landing of the Huygens Probe is an enormous tribute to the ESA led international team," said Louis Friedman, Executive Director of The Planetary Society. "The engineering success is a tremendous achievement, and we look forward to rich science return from the exciting exploration now underway at Titan."
Stay tuned for more about the sounds of Titan in the days ahead when new information will be posted on the Society's website. Follow the Cassini-Huygens mission with the Society's other special web features, including updates from Huygens mission control written by Planetary Society staffer Emily Lakdawalla who is currently in Germany.