http://arxiv.org/abs/1805.01306
Breakthrough Starshot is an initiative to prove ultra-fast light-driven nanocrafts, and lay the foundations for a first launch to Alpha Centauri within the next generation. Along the way, the project could generate important supplementary benefits to solar system exploration. A number of hard engineering challenges remain to be solved before these missions can become a reality.
A system model has been formulated as part of the Starshot systems engineering work. This paper presents the model and describes how it computes cost-optimal point designs. Using the model, three scenarios are examined: A 0.2 c mission to Alpha Centauri, a 0.01 c solar system precursor mission, and a ground-based test facility based on a vacuum tunnel. All assume that the photon pressure from a 1.06 {\mu}m wavelength beam accelerates a circular dielectric sail. The 0.2 c point design assumes \$0.01/W lasers, \$500/m$^2$ optics, and \$50/kWh energy storage to achieve \$8.3B capital cost for the ground-based beam director. In contrast, the energy needed to accelerate each sail costs \$7M. Beam director capital cost is minimized by a 4.2 m diameter sail that is accelerated for 10 min. The 0.01 c point design assumes \$1/W lasers, \$10k/m$^2$ optics, and \$100/kWh energy storage to achieve \$517M capital cost for the beam director and \$8k energy cost to accelerate each 19 cm diameter sail. The ground-based test facility assumes \$100/W lasers, \$1M/m$^2$ optics, \$500/kWh energy storage, and \$10k/m vacuum tunnel. To reach 20 km/s, fast enough to escape the solar system from Earth, takes 0.3 km of vacuum tunnel, 16 kW of lasers, and a 0.9 m diameter telescope, all of which costs \$6M.
The system model predicts that, ultimately, Starshot scales to cruise velocities of greater than 0.9 c.
K. Parkin
Fri, 4 May 18
4/65
Comments: N/A