The Breakthrough Starshot system model

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. Three point designs are computed: 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 μm wavelength beam accelerates a circular dielectric sail. The 0.2 c point design assumes 0.01/W lasers, 500/m² optics, and 50/kWh energy storage to achieve 8.0B capital cost for the ground-based beam director. In contrast, the energy needed to accelerate each sail costs 6M. Beam director capital cost is minimized by a 4.1 m diameter sail that is accelerated for 9 min. The 0.01 c point design assumes 1/W lasers, 10k/m² 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/m² optics, 500/kWh energy storage, and 10k/m vacuum tunnel. To reach 20 km s^-1, fast enough to escape the solar system from Earth, takes 0.4 km of vacuum tunnel, 22 kW of lasers, and a 0.6 m diameter telescope, all of which costs 5M.

The system model predicts that, ultimately, Starshot can scale to propel probes faster than 0.9 c.