November 25, 2004

Scientists Gather at UA to Plan Cassini Probe’s Drop to Titan

Scientists from around the world were at the UA this week planning the Christmas release of a probe to study Titan, Saturn's largest moon.

The Huygens probe will separate from the spacecraft Cassini on Dec. 25 and begin its descent to the surface of Titan as part of NASA's Cassini-Huygens mission. The University of Arizona has more than two dozen researchers working on the $3.4 billion mission, more than any other university.

Six testing instruments are on board the Huygens probe, including the Descent Imager/Spectral Radiometer, which will take photographs of Titan's surface as the probe descends. UA professor Martin Tomasko leads that experiment.

The desire for a mission to Titan began forming more than 20 years ago, after Voyager 1 flew by in 1980, said UA professor Jonathan Lunine, an interdisciplinary scientist for the Huygens probe.

Titan has the last unexplored, earthlike environments in the solar system and is one of the few places in the solar system containing connections to the origin of life - organic molecules, Lunine said.

Titan - which is 10 times as far from the sun as Earth and has an average temperature of 300 degrees below zero Fahrenheit - is considered a frozen laboratory of what early Earth might have looked like, said Michael Drake, director of the UA's Lunar and Planetary Laboratory.

The images the Descent Imager/Spectral Radiometer will capture during its descent to Titan will be assembled into panoramic mosaics. Scientists have been using DISR images taken around Picacho Peak to plan how they will interpret data and create panoramic views and maps of Titan's surface.

"One of the main objectives of this instrument is to understand the nature of Titan's surface," Tomasko said.

"It's possible the early chemical steps of life are being replicated on the surface of Titan. That's why the surface is so interesting to us," Lunine said.

The Cassini-Huygens mission is a joint endeavor of NASA, the European Space Agency and the Italian space agency, Agenzia Spaziale Italiana.

"Without ESA, we would not have had this mission," Lunine said.

The Dec. 25 release of the probe will be the culmination of 14 years of work, Lunine said. Scientists laid plans for the mission between 1983 and 1990, and built equipment from 1990 to 1997, when Cassini-Huygens was launched.

The Huygens probe - named for Dutch scientist Christiaan Huygens, who discovered Titan in 1655 - is scheduled to separate from the Cassini spacecraft Dec. 25, and will be carried toward Titan as a series of parachutes are deployed. The probe will arrive at Titan Jan. 14.

One of Titan's interesting characteristics is that it has methane in its atmosphere, a feature discovered in the 1940s by planetary astronomer Gerard Kuiper. Kuiper founded the UA's Lunar and Planetary Laboratory in 1960, so it can be said the university has a 60-year relationship with Titan, Lunine said.

Titan makes for a good study subject because it is one of the largest moons in the solar system, Lunine said. It has a dense atmosphere - the other three bodies with such atmospheres are Venus, Earth and Mars.

"Titan is not a dead moon, but a place that has been geologically active. Titan will be a rewarding world to study," Lunine said.

* Contact reporter Mary Vandeveire at 573-4195 or [email protected]