Imagine listening to a violent storm - the whoosh of the wind, the crack of thunder. Now imagine listening to one a billion miles away in the dense atmosphere of Saturn's moon Titan! The Earth's public may soon have the chance to hear the winds of an alien world when The Planetary Society teams up with the European Space Agency and the Huygens Atmospheric Structure Instrument team to release the sounds recorded by the Huygens probe during its descent through Titan's atmosphere on January 14, 2005.
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 will listen to the probe's entire descent, detecting turbulence in the air and possibly even the thunder due to lightning in Titan's skies. The public can listen to the sounds recorded by Huygens on the Planetary Society's website when the data is posted on Saturday, January 15 at http://planetary.org/sounds/.
"The public has seen pictures of other worlds for decades, but now they'll be able to hear another world a billion miles away," said Planetary Society Director of Projects, Bruce Betts. "Hearing the sounds of Titan promises to be amazing!"
Because the Huygens probe is only expected to live about two and a half hours from the time it hits the top of Titan's atmosphere, all the data collected must be transmitted live to Cassini. That means that data has to be 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 records 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. Once Delory has processed the data, the sounds posted on The Planetary Society's website will be much more similar to the noises one would actually hear during the probe's descent. Those sounds might include the rush of the atmosphere, wind, thunder from local storms, the deployment of the probe's braking parachutes, the noise of Huygens' impact on the surface (which could be liquid or solid), and maybe even the splash of liquid methane rain!
On January 13, The Planetary Society is hosting a public event in Pasadena, California to celebrate Huygens' arrival at Titan the following day. Former Jet Propulsion Director Ed Stone, actor Robert Picardo, Huygens engineer Shaun Standley, Cassini scientist Linda Spilker, and Bill Nye the Science Guy are among the speakers who will present an evening about Cassini, Huygens, Voyager, and the timeless allure of Saturn.