Cost-Optimal System Performance Maps for Laser-Accelerated Sailcraft [IMA]

http://arxiv.org/abs/2205.13138


Breakthrough Starshot is an initiative to explore the Centauri system using laser-accelerated sailcraft. Earlier work produced a point design for a 0.2 c mission carrying 1 g of payload. The present work widens the design space to missions having 0.1 mg to 100 kt payload and 0.0001-0.99 c (6-60,000 au/yr) cruise velocity. Also, the beam director may now draw up to 5 GW of power directly from the grid to augment the power drawn from its energy storage system. Augmenting stored energy with grid power shrinks beam director capital cost by 1-5 orders of magnitude. The wider design space encompasses new possibilities: A 0.1 mg microbiome accelerated to 0.01 c in only 2 min by a beam director that expends \$6k worth of energy. A 10 kg Solar system cubesat accelerated to 0.001 c (60 au/yr) by a \$600M beam director that expends \$60M worth of energy per mission. A progression from cost-optimized point designs to whole performance maps has been made possible by replacing numerical trajectory integration with closed-form equations. Consequently, the system model now computes 1-2 orders of magnitude more point designs per unit time than before. Resulting maps reveal several different solution regimes that are characterized by their performance-limiting constraints. The performance maps also reveal a family of missions that accelerate at Earth gravity. The heaviest such mission is a 2 km diameter 100 kt vessel (equivalent to 225 International Space Stations) that is accelerated for 23 days to achieve 0.07 c, reaching the Centauri system within a human lifetime. While unthinkable at this time, the required 340 PW peak radiated power (twice terrestrial insolation) might be generated by space solar power or fusion within a few centuries. Regardless, it is now possible to contemplate such a mission as a laser-accelerated sailcraft.

Read this paper on arXiv…

K. Parkin
Fri, 27 May 22
22/61

Comments: N/A