CU researchers playing big part in Saturn mission, orbiting June 30

By David Brand

Cornell researchers are playing a major role in yet another planetary space mission, this time to Saturn, the second largest planet in the solar system. On June 30 at approximately 10:30 p.m. EDT, NASA's Cassini-Huygens spacecraft will go into orbit around Saturn for an extensive tour of the giant planet's rings and 31 known moons.

This image of Saturn was taken by the Cassini-Huygens spacecraft's narrow angle camera May 16. NASA/JPL/Space Science Institute

Launched in 1997, Cassini is the best-equipped spacecraft ever sent to another planet, and one of the most powerful of its 12 scientific instruments is the Huygens probe, which will begin a long descent to the surface of Saturn's giant moon, Titan, in December. The small cone-shaped probe, which will coast for 22 days as it descends into Titan's cloudy atmosphere, itself carries six sensitive instruments to study the moon's atmosphere and surface.

A camera will make more than a thousand images of Titan's surface and clouds. Another instrument will use radio signals to measure Titan's winds. Three sensors will analyze the moon's atmosphere. If it survives the landing, Huygens will measure Titan's surface.

Cornell researchers on the Cassini imaging team are Joseph Burns, the Irving Porter Church Professor of Engineering, Theoretical and Applied Mechanics, professor of astronomy and Cornell's vice provost for physical sciences and engineering; Joseph Veverka, professor and chair of the Department of Astronomy; Steve Squyres, professor of astronomy; and Peter Thomas, senior researcher in astronomy. The team has two CCD cameras that will take pictures in the visible, near-infrared and near-ultraviolet light; one is a wide-angle telescope to see broad areas while the other sees 10 times better.

Completing the Cornell contingent are professors of astronomy Peter Gierasch, who is on the composite infrared spectrometer team, and Philip Nicholson, who is on the visual infrared mapping spectrometer team. Nicholson's instrument has much lower resolution than the CCD cameras, but it detects much longer wavelengths. It also can do a better job of determining the chemical makeup of the surfaces, atmospheres and rings.

The $3 billion mission represents the technical expertise of 260 scientists from the United States and 17 European nations. The science instruments will study Saturn's rings, icy satellites and magnetosphere, as well as Titan.

For the critical Saturn orbit insertion maneuver, the spacecraft will fire its main engine for 96 minutes. This will reduce Cassini's speed and allow it to be captured into orbit as a satellite of Saturn. Cassini will pass through a gap between two of Saturn's rings, then swing close to the planet and begin the first of 76 orbits around the Saturn system. During the mission, it will execute 52 close encounters with Saturn's moons.