Boffins reveal yet more of Titan's secrets
Plenty to see here
Scientists were dismayed when, as they watched the Huygens probe fall to the surface on Saturn's moon Titan, one of its key experiments failed.
At the time, it looked like vital science would be lost, but now, after two years of painstaking reconstruction, the teams have been able to piece together an astonishingly detailed picture of the moon, its surface, and atmosphere.
The latest reconstruction of Titan's surface
The additional information gleaned from the data has allowed researchers to build more accurate computer models of the world. For instance, the latest model of the winds reveals that the atmosphere behaves like a giant conveyor belt, circulating its gas from the south pole to the north pole and back again.
Although the probe could only be heard for around four hours after entering Titan's atmosphere, the researchers say the data it sent back is so rich they still have not squeezed all the information from it.
Professor John Zarnecki of The Open University led the Surface Science Package (SSP) on Huygens: "Huygens has provided us with a rich seam of data to mine – and we shall be digging through it for some time to come. The Surface Science Package returned immediate information about Titan about the landing Huygens made but it is also a part of the longer term picture, piecing together the whole environment on Titan."
The analysis has also turned up some suggestive data: researchers have tentatively identified an extremely low frequency (ELF) radio wave. This has all the planetary scientists particularly excited. If it is confirmed as a natural phenomenon, it will give them a way to probe into the moon's subsurface, to search for things like underground oceans.
Even the failed instruments have added to the gold mine of raw data. The Doppler Wind Experiment is a good example of this kind of emergency scientific analysis. When the radio channel that should have sent back that data failed, the researchers hunted for another way to track the signal. It transpired that it could still be picked up from Earth, and teams were still able to build a useful wind profile and put many of the probe's images of the alien world into their correct context.
Now, they have even been able to refine their picture of the moon's atmosphere by using data from other instruments to add to the knowledge from the emergency version of the DWE.
The Huygens research team at ESA (European Space Agency) used measurements from the other instruments, such as the temperature and pressure data the Huygens Atmosphere Structure Instrument (HASI) collected on the descent, as well as data from the SSP, to flesh out the sketch they had already drawn of probe's descent through Titan's atmosphere.
The SSP, for instance, revealed a particularly turbulent atmospheric layer between 20 and 30 kilometres from the surface. By comparing the motions in this layer with those recorded on terrestrial balloons, Ralph Lorenz, of the Johns Hopkins University Applied Physics Lab, and his SSP colleagues suggest the turbulence may have been associated with clouds. ®