Magnetoshell Aerocapture: Advances Toward Concept Feasibility

Thesis (Master's)--University of Washington, 2018Magnetoshell Aerocapture (MAC) is a novel technology that proposes to use drag on a dipole plasma in planetary atmospheres as an orbit insertion technique. It aims to augment the benefits of traditional aerocapture by trapping particles over a much larger area than physical structures can reach. This enables aerocapture at higher altitudes, greatly reducing the heat load and dynamic pressure on spacecraft surfaces. The technology is in its early stages of development, and has yet to demonstrate feasibility in an orbit-representative environment. The lack of a proof-of-concept stems mainly from the unavailability of large-scale, high-velocity test facilities that can accurately simulate the aerocapture environment. In this thesis, several avenues are identified that can bring MAC closer to a successful demonstration of concept feasibility. A custom orbit code that dynamically couples magnetoshell physics with trajectory propagation is developed and benchmarked. The code is used to simulate MAC maneuvers for a 60 ton payload at Mars and a 1 ton payload at Neptune, both proposed NASA missions that are not possible with modern flight-ready technology. In both simulations, MAC successfully completes the maneuver and is shown to produce low dynamic pressures and continuously-variable drag characteristics. A generalized magnetoshell design framework is described for application to satellites of any scale. This framework is applied to develop a flight demonstration mission aboard a 3U CubeSat with a deployable electromagnet. The CubeSat configuration considered here proves to be intractable due to limitations on stored energy, mass, and deployment scheme. As an alternative to a flight demonstration, a laboratory proof-of-concept is proposed as a subscale magnetoshell interacting with a neutral particle flow in an experimental setting. The suitability of neutral beams used in silicon etching is considered for use as a flow source. An experimental design is proposed using such a source. Investigative techniques are considered that aim to characterize the power and fuel requirements of the plasma as well as the structure of the flow ionization region. This experiment can resolve the difficulties of both full-scale ground testing and in-orbit demonstration. The work in this thesis advances MAC closer to realization in interplanetary missions, enabling experimentalists and mission planners to further develop the technology. By addressing some of the biggest impediments to successful demonstration, this thesis helps to push MAC toward competitiveness with other proposed aerocapture solutions