Descent motions of the Huygens probe as measured by the Surface Science Package (SSP): Turbulent evidence for a cloud layer

Citation

Ghafoor NAL, Hagermann A, Lorenz RD, Zarnecki JC, Towner MC, Leese MR, Ball AJ & Hathi B (2007) Descent motions of the Huygens probe as measured by the Surface Science Package (SSP): Turbulent evidence for a cloud layer. Planetary and Space Science, 55 (13), pp. 1936-1948. https://doi.org/10.1016/j.pss.2007.04.007

Abstract
The Huygens probe underwent vigorous short-period motions during its parachute descent through the atmosphere of Saturn's moon Titan in January 2005, at least some of which were excited by the Titan environment. Several sensors in the Huygens Surface Science Package (SSP) detect these motions, indicating the transition to the smaller stabilizer parachute, the changing probe spin rate, aerodynamic buffeting, and pendulum motions. Notably, in an altitude range of about 20-30 km where methane drops will freeze, the frequency content and statistical kurtosis of the tilt data indicate excitation by turbulent air motions like those observed in freezing clouds on Earth, supporting the suggestion of Tokano et al. [Tokano, T., McKay, C.P., Neubauer, F.M., Atreya, S.K., Ferri, F., Fulchignoni, M., Niemann, H.B. (2006a). Methane drizzle on Titan. Nature 442, 432-435] that the probe passed through such a cloud layer. Motions are weak below 20 km, suggesting a quiescent lower atmosphere with turbulent fluctuations of nominally

Keywords
Space and Planetary Science; Astronomy and Astrophysics

Journal
Planetary and Space Science: Volume 55, Issue 13