Sylph: Life Detection Probe for a Europa Plume

Jupiter’s Galilean satellite Europa likely contains a vast, global, subsurface salt-water ocean. A singular telescope observation in 2012 indicated possible plume activity, in some ways similar to the continuous plume activity seen at Enceladus. If a Europan plume does expel ocean water into space, its vapor, ice grains, and dust grains could be analyzed by a spacecraft equipped with high-resolution mass spectrometers. Such plume measurements would be sufficient to measure the contextual habitability profile of the ocean, and to detect multiple signatures of life, should it exist in the ocean. Instrumented with MASPEX (Mass Spectrometer for Planetary Exploration) and SUDA (Surface Dust Analyzer), NASA’s planned Europa Mission now in development could theoretically conduct this investigation. However, the mission’s closest flyby altitude would be 25 km; due to Europa’s large gravity, frozen ocean spray containing non-volatile molecular species critical to biosignature detection can be sampled only within 5 km of the surface. The Europa Mission would not fly this low. Sylph is a concept for a complementary, free-flyer smallsat probe, about the same size as an office water-cooler bottle, that could be deployed by the Europa Mission as it conducts a plume fly-through. Sylph would execute a single ~2 km altitude plume pass below the main spacecraft. With a mass of 40 kg and a 24-hr life, the probe would autonomously navigate its low-altitude pass, and carry a dualchannel Mini-SUDA impact ionization mass spectrometer that would measure the composition of large grains, complementing the main spacecraft’s measurements of small grains and gas. Sylph is a novel smallsat concept: purpose-built configuration optimized for both the harsh Jovian environment and for Europan planetary-protection requirements, and built with advanced manufacturing methods from both deep space and smallsat components. For $80M (~4% marginal cost), the Europa Mission could buy a Sylph “insurance policy,” hedging the possibility that it does discover ocean plumes upon arrival in 2028. At less than 85 kg for probe and accommodations, the mission could carry two or three of the probes.