Grappler: Array of bistable elements for pinching net-like infrastructure to low gravity bodies

Near-Earth asteroids and comets are ubiquitous and are key destinations for studying the formation of our solar system. These bodies may also one day serve as resource restocking de-pots for longer duration missions. However, in-situ scientific analysis requires the development of microgravity-tolerant landers that are not subject to recoil on impact. Whereas prior art focuses primarily on anchoring and hopping mechanisms, this paper evaluates a novel mission architecture in which chains of bistable pinching elements called grapplers are used to land net-like infrastructure on low gravity bodies. Unlike single-point-of-contact landers, a net that is successfully adhered to an asteroid may serve broad and flexible use in the exploration of small bodies. For example, it may constitute infrastructure to enable locomotion of a swarm of distributed crawling sensors and actuators for high resolution study of the body’s interior structure and surface properties. It may also serve as a foundation onto which larger scale sensing and communication structures can be built over time. Finally, it may serve as a series of hand holds used by astronauts to maneuver around the body. To adhere the net to a body, microgravity flight testing of a representative Grappler prototype demonstrates the tolerance of a bistable chain to variable impact conditions and terrain contours owing to the inherent adaptivity of the chain’s pinching configuration-for a chain of n bistable elements, 2ⁿ pinching configurations are possible. These pinching elements can be integrated sparsely or densely into net-like infrastructure. A computational model is also presented. Grapplers are compared to alternative net adhesion strategies ranging from passive wrapping to chemical rigidization.