Ultra-high acceleration neutral particle beam-driven sails

J. Benford et al. (2019), JBIS, 72, pp.190-197

Refcode: 2019.72.190

Abstract:
The authors advance the concept for a 1 kg probe that can be sent to a nearby star in about seventy years using neutral beam propulsion and a magnetic sail. The concept has been challenged because the beam diameter was too large, due to inherent divergence, so that most of the beam would miss the sail. Increasing the acceleration from 1000 g to 100,000 g along with reducing the final speed from 0.1 c to 0.06 c redeems the idea. Such changes greatly reduce the acceleration distance so that the mission can be done with realistic beam spread. Magsail-beam interaction remains an aspect of this concept that needs further study, probably by simulations. We describe key elements of neutral particle beam generators, their engineering issues, cost structure and practical realities. Comparison with the Starshot laser beam-driven concept gives roughly similar costs.