Science Investigations From Multiple Deep (100 Bar) Jupiter Atmospheric Entry Probes

T.R. Spilker (JPL/Caltech), W.B. Hubbard (LPL/U of Ariz)

Sampling temporally and spatially varying planetary atmospheres using single entry probes risks obtaining a nonrepresentative sample, as demonstrated by the Galileo entry probe’s descent into a 3-sigma “hot spot.” Multiple entry probes reduce this risk and examine an atmosphere’s spatial variability. The Galileo probe’s results suggest that at Jupiter, deep probes (reaching pressure levels of  100 bars or more) are needed to answer important questions about the composition and dynamics of the deep troposphere. For example, zonal wind speeds were still accelerating with depth at 21 bars, the deepest datum, so the depth of penetration of Jupiter's zonal flow structure is still unverified. Consequently, the Astrophysical Analogs Campaign Science Working Group has identified multiple deep Jupiter entry probes as their top priority for a near-term space flight mission, and has identified and prioritized science investigations for such a mission. Those investigations, and the instrument complement to conduct them, will be described. Studies conducted at JPL in 1996 and 1997 suggest implementation strategies that should make the mission more attractive to NASA than previous mission designs for multiple Jupiter entry probes. Recent innovations, such as miniaturized mass spectrometers now under development and a new mission design that does not require a Jupiter-orbiting relay spacecraft, have significantly reduced the estimated cost of a three-probe mission. This work was performed at the Jet Propulsion Laboratory / California Institute of Technology under contract to the National Aeronautics and Space Administration.