23 July 2004The Cassini-Huygens Scientists presented their latest results to a press briefing organised at COSPAR on Friday 23 July. These results were a preview of the papers that will be presented at the special Cassini-Huygens session on Saturday 24 July. The panel was composed of the following speakers:
- Dennis Matson, JPL/NASA, Overview
- Phillipe Zarka, Obs. Paris-Meudon, Saturn lightning
- Michelle Dougherty, Imperial College, London; Engine burn observations
- Stamatios (Tom) Krimigis, Applied Physics Laboratory, JHU, Baltimore, Discovery of a new Saturn radiation belt
- Ralf Srama, MPI, Heidelberg, Saturn dust streams
- Larry Esposito, Unv. Of Colorado, Denver, Ring UV images
- Mike Flasar, GSFC/NASA, Greenbelt, Titan spectra and Titan winds
- Robert (Bob) Brown, Univ. of Arizona, Tucson, Titan atmosphere and surface images
Jean-Pierre Lebreton, ESA, acted as the moderator.
Some of the significant results included the following:
- Radio-wave detection of Saturn lightning, was made in a wide frequency range extending as high as 16 MHz. Multiple bursts of lightning-generated radio signals were detected suggesting multiple storm systems were active around Saturn during the post Saturn Orbit Insertion.
- The magnetometer detected low-frequency plasma waves related to the presence of gases from the Cassini main engine exhaust cloud. This detection occurred up to 2 hours after the completion of the burn indicating that the cloud lived much longer than expected.
- The Magnetospheric Imaging Instrument discovered, thanks to its new imaging technique, a new radiation belt just above Saturn's cloud tops up to inner edge of the D-ring. This is the first time that a new radiation belt was discovered with a remote sensing technique.
- The Cosmic Dust Analyser detected dust streaming out of Saturn's rings. These tiny smoke-like particles were detected up to 1000 Saturn radii away (60 millions km) from Saturn's environment. An other highlight is the detection of a dust particle with a charge up to 2 times greater than any previous detection. This is an important discovery that will help better understand the interaction between charged dust particles and Saturn's magnetic environment.
- The Principle Investigator of the Ultraviolet Imaging Spectrograph offered two possible scenarios that could explain the variation of the icy composition of the main rings as we move away from Saturn. The first is that different parent bodies broke apart to form different parts of the ring. The second is that outside meteoritic material contaminated different regions of the rings.
- The Composite infrared Spectrometer measured the temperature contrast of the atmosphere in Titan's southern hemisphere, well within the range of the expected values used to design the Huygens mission. This temperature map was used to derive wind speeds in the upper atmosphere of Titan. A maximum near the equator of 140 m/s ( 500 km/h) was obtained. Mike Flasar commented: "This is ten times faster than Lance Armstrong and Ivan Basso".
- The Team Leader of the Visual and Infrared mapping spectrometer offered new interpretation of the observations of Titan and presented new images of Titan surface and of its atmosphere all obtained on 2nd July. The first detection of the methane glow up to 600 km on the sunlit side in Titan's upper atmosphere was reported. Surface features include a possible large crater, and a 2000 km long valley. Bob Brown said: "It may be similar to Valles Marineris on Mars".
The supporting material for this announcement, in the form of an 8 Mb zip file, can be downloaded here.
This summmary report was written by:
Huygens Mission Manager/Project Scientist
tel: +(31) 71 565 3600
Deputy Cassini Project Scientist
tel: +(1) 818 354 1647