8.1.6 Moon artillery
Penetrators are being designed to get instruments onto the surface of Europa, without the need for a more expensive ‘soft landing’ and to look into its subsurface without having to drill. Penetrators are essentially instrument-carrying ballistic shells. Such a shell fired into Europa from an orbiter or flyby spacecraft could allow us to measure directly whether the environment has the correct chemical signatures for biological material. This type of technology can also be used on rocky surfaces such as the Moon. This work has shown promising results and has been proposed for future missions to both Europa and the Moon.
A research group (CESPAR) at The Open University has been testing miniaturised mass spectrometer instruments for use in high-impact penetrator systems, such as that shown in the image above. These miniaturised systems are designed to analyse the subsurface material on moons and small bodies, but first they must survive the shock of very high deceleration during impact, so avoiding the need for soft-landing systems and drilling. Because they end up one metre or so below the surface, penetrators also enable us to make measurements of interior heat and structure. A single spacecraft could in principle deliver several penetrators to different places on a target body.