An Ice Shell Impact Penetrator (IceShIP) for Organic Analysis on Europa

Abstract:

Kinetic penetrators have the potential to enable low cost in situ measurements of the ice shells of astrobiologically exciting worlds including Europa and Enceladus [1]. Their small size and mass, critical to limiting their kinetic energy to an acceptable range, makes them ideal small landers riding on primarily orbiter missions, while still enabling sampling at several m depth due simply to burial and excavation. In situ microfluidic-based organic analysis systems are a powerful, miniaturized approach for detecting markers of habitability and recent biological activity.

Further development of microfluidic technology, like that of the Mars Organic Analyzer (MOA) [2,3] and Enceladus Organic Analyzer (EOA), will lead to an instrument capable of in situ biomarker analysis compatible with a kinetic penetrator platform. This technology uses an integrated microfluidic processor to prepare samples for microchip capillary electrophoresis (µCE), where amine and amino acid components are chirally and compositionally separated prior to highly sensitive laser-induced fluorescence (LIF) detection.

Preliminary modeling of the core microfluidic processing and analytical device indicates that the device is more than capable of surviving the stresses associated with an impact acceleration of >50,000g. However, a number of developments must still be made to both the microdevice itself and the supporting hardware to enable a system truly capable of surviving such large g-loads upon impact.

Preliminary experiments indicate that switching to an incompressible (hydraulic) microvalve system may provide better impact resistance. A modification of an established microfabricated LIF detection system would use indium bump bonding to permanently weld optical components using standard microfabrication techniques with perfect alignment. Incorporation of microfabricated electrodes within the microdevice can enable robust and simple measurements of pH, total ion content, and potentially even individual ion concentration without adding significant mechanical complexity or risk.

References: [1] Gowen et al., Adv. Space Res., 2011, 725. [2] Skelley et al, PNAS USA, 2005, 102, 1041. [3] Kim J., et al, Anal. Chem., 2013, 85, 7682.