Researchers reconstructed the landing of the European Space Agency's Huygens probe, ferried to Titan by NASA's Cassini spacecraft, by analyzing data from a variety of instruments that were active during the impact as the probe bounced, slid and wobbled it way to rest in 10 seconds during its January 2005 landing.
They compared the data with results from computer simulations and a drop test using a model of Huygens designed to replicate the landing.
While previous research suggested Titan's surface is quite soft, the new work goes one step farther to demonstrate that if something put little pressure on the surface the surface was hard, but if an object put more pressure on the surface it sank in significantly, a NASA release reported Thursday.
"It is like snow that has been frozen on top," researcher Erich Karkoschka at the University of Arizona said. "If you walk carefully, you can walk as on a solid surface, but if you step on the snow a little too hard, you break in very deeply."
The Huygens probe, which had a mass of about 400 pounds, hit the surface of Titan with an impact speed similar to dropping a ball on Earth from a height of about 3 feet.
"This study takes us back to the historical moment of Huygens touching down on the most remote alien world ever visited by a landing probe," ESA Cassini-Huygens project scientist Nicolas Altobelli said. "Huygens data, even years after mission completion, are providing us with a new dynamical 'feeling' for these crucial first seconds of landing."