Sample Return Instrumentation for Small Solar System Bodies

To date, return sampling (except for the Moon) has been limited to surface samples which have been modified by solar wind interactions, and/or micrometeor impacts. This proposal seeks to use the kinetic energy of an approaching spacecraft to produce a self-ejecting core sample of the first few meters from small solar system objects. This sub-surface core will be the first of its type and will provide new information the content, origin and evolution of the solar system and the potential for life elsewhere. It will also provide new information as to why asteroids appear to have additional cohesive forces that prevent rotational break up, and determine variations in the composition from the capture of different bodies. The system will be also be able to capture organic compounds (if present), which will aid in understanding the origins of life. The system also has the advantage that it requires less wet mass relative to soft-landing drilling approaches. The system operates in the velocity regime of 300-600 m/s which is typical of spacecraft approach speeds to an asteroid prior to any braking. At this speed impact pressures are sufficient to exceed the tensile strength of most rocks and allow the penetrator to bury into the sample to several feet, yet it is sufficiently slow to allow for the penetrator to remain intact after the impact. Entry ports in the nosecone of the penetrator allow material to flow into the center core where it will be collected by a sample return system. The bounce energy from the impact is sufficient to cause the collected sample to be ejected from the impact site of speeds of a few 10's m/s. Depending on the escape velocity of the solar system object, the system would be optimize for pick up in space or for surface retrieval. The penetrator system and sample ejection have been demonstrated giving it an initial TRL of 3 through optimization of the system for different rock material still has to occur. The retrieval system is only at the concept stage and will require radar location and electromagnetic pickup. This proposal seeks to advance these subsystems to TRL 3 or greater through modeling, laboratory testing and field prototyping. This effort will include (a) modeling to validate performance of different impact angles, (b) the ability of successful penetration irrespective of the hardness and roughness of the target terrain, (c) the collection of sample and its ejection within the sample return canister after impact and (d) demonstration of the ability to recover the sample return canister onto the main payload. Through these efforts, we will fully demonstrate core rock sample that is self-ejected under a variety of different rock impacts and impact velocities thereby demonstrating the versatility of the system for multiple NASA applications. More »