The Huygens probe, supplied by the European Space Agency, carries a well-equipped robotic laboratory that it will use to scrutinize the clouds, atmosphere, and surface of Saturn's moon Titan. As the 2.7-meter-diameter (8.9-foot) probe enters the atmosphere it will begin taking measurements in the haze layer above the cloud tops. As it descends -- first on a main parachute and later on a drogue chute for stability -- various instruments will measure the temperature, pressure, density, and energy balance in the atmosphere.
As the Huygens probe breaks through the cloud deck, a camera will capture pictures of the Titan panorama. Instruments will also be used to study properties of Titan's surface remotely -- and perhaps directly, should the probe survive the landing.
Many scientists theorize that Titan may be covered by lakes or oceans of methane or ethane, so the Huygens probe is designed to function even if it lands in liquid. If the battery-powered probe survives its landing, it will relay measurements from Titan's surface until the Cassini orbiter flies beyond the horizon and out of radio contact.