One week after the successful completion of Huygens' mission to the atmosphere and surface of Titan, the largest and most mysterious moon of Saturn, the European Space Agency is bringing together some of the probe's scientists to present and discuss the first results obtained from the data collected by the instruments.
After a 4000 million kilometre journey through the Solar System that lasted almost seven years, the Huygens probe plunged into the hazy atmosphere of Titan at 11:13 CET on 14 January and landed safely on its frozen ground at 13:45 CET. It continued transmitting from the surface for several hours, even after the Cassini orbiter dropped below the horizon and stopped recording the data to relay them towards Earth. Cassini received excellent data from the surface of Titan for 1 hour and 12 minutes.
More than 474 megabits of data were received in 3 hours 44 minutes from Huygens, including some 350 pictures collected during the descent and on the ground, which revealed a landscape apparently modelled by erosion with drain channels, shoreline-like features and even pebble-shaped objects on the surface.
The atmosphere was probed and sampled for analysis at altitudes from 160 km to the ground, revealing a uniform mix of methane with nitrogen in the stratosphere. Methane concentration increased steadily in the troposphere down to the surface. Clouds of methane at about 20 km altitude and methane or ethane fog near the surface were detected.
The probe's signal, monitored by a global network of radio telescopes on Earth, will help reconstruct its actual trajectory with an accuracy of 1 km and will provide data on Titan's winds. Early analysis of the received signal indicate that Huygens was still transmitting after three hours on the surface. Later recordings are being analysed to see how long Huygens kept transmitting from the surface.
Samples of aerosols were also collected at altitudes between 125 and 20 km and analysed onboard. During the descent, sounds were recorded in order to detect possible distant thunder from lightning, providing an exciting acoustic backdrop to Huygens's descent.
As the probe touched down at about 4.5 metres per second, a whole series of instruments provided a large amount of data on the texture of the surface, which resembles wet sand or clay with a thin solid crust, and its composition, mainly a mix of dirty water ice and hydrocarbon ice, resulting in a darker soil than expected. The temperature measured at ground level was about -180 degrees Celsius.
Some stunning preliminary results were presented shortly after the science teams obtained access to their data, on 15 January. After several days of processing and analysis of these results, the scientists will be able to deliver a better view of this strange distant world during a press conference on Friday 21 January at 11:00 CET at ESA's Headquarters in Paris (rebroadcast at several other ESA establishments).
Source: Eurekalert & othersLast reviewed: By John M. Grohol, Psy.D. on 21 Feb 2009
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