Starshot System Model

The Breakthrough Starshot system model draws an ontology of simpler models to compute cost-optimal interstellar mission point designs.

This is a non-public model: Requests for access may be directed to Breakthrough Initiatives.

Reference Cases

(please run only one or two of these at once to minimize the load on the datacenter)

0.2 c Centauri System Convergence Missions:[t%E2%82%84=0].%CE%B2=0.2?

100 au/yr Solar System Science Chipsats:[t%E2%82%83=0].Motion.RTA.A=1e-05?Beamer.Lasers.CapEx.$/W=1?[t%E2%82%84=0]

10 au/yr Solar System Polar Cubesat:$/W=1?[t%E2%82%83=0].Motion.RTA.A=0.0001?Beamer[t%E2%82%83=0].Motion.RTA.R=0.2?

30 au/yr Ecliptic Picosat:$/=0.1?

Tau Ceti Human Mission:[[t%E2%82%83=.M.R.R=0.9?Sy.P.maxi=0.001?Beamer.B.%CE%B7%E2%82%83%E2%82%90=1?Beamer.n=1000?[t%E2%82%84.%CE%B2=0.7?

Trappist-1 Human Mission:[[t%E2%82%83=.M.R.R=0.9?Sy.P.maxi=0.001?Beamer.B.%CE%B7%E2%82%83%E2%82%90=1?Beamer.n=1000?[t%E2%82%84.%CE%B2=0.99?

Adjustable inputs (not exhaustive)

Description Variable name
Cost of energy generation and transmission to beam director site per pulse [$/kWh] Beamer.Rate_per_pulse
Number of missions that the beamer is cost-optimized for (capital cost of beamer plus energy cost of this many missions is the quantity that is minimized) Beamer.n
Fraction of transmitted laser power that successfully exits the atmosphere (is not lost to scattering or absorption) Beamer.Beam.η₃ₐ
Initial distance between laser source and lightsail Beamer[t₃=0]
Fraction of wallplug to transmitted laser power Beamer.Lasers.η
Laser capex per unit power Beamer.Lasers.CapEx.$/W
Optics capex per unit area Beamer.Optics.CapEx.$/m²
Energy storage capex per kWh of capacity Beamer.Storage.CapEx.$/kWh
Grid to storage energy transfer efficiency Beamer.Storage.η₁₂
Storage to radiated energy transfer efficiency Beamer.Storage.η₂₃
Maximum power provided by the grid (e.g. via transmission lines) that is not provided from locally stored energy Beamer.Storage.P₁_max.GW
Areal density of sail material (excludes payload) Sailcraft.Substrate.ρₐ.g/m²
Lightsail absorptance Sailcraft.Substrate.Optical.A
Lightsail reflectance Sailcraft.Substrate.Optical.R
Lightsail total hemispherical emissivity Sailcraft.Substrate.Thermal.ε
Maximum allowable lightsail temperature Sailcraft[T⁺].Substrate.Thermal.T.K
Lightsail cruise velocity Sailcraft[t₄=0].β.c

Notable outputs (not exhaustive)

Description Variable name
Capital cost of the beam facility needed to carry out the specified mission(s) Mission.CapEx
Lightsail payload fraction Mission.M₂/M₀
Mission capex per unit payload Mission.CapEx/M₂
Payload specific energy cost Mission.M$/M₂_PP
Time dilation factor in cruise Sailcraft[t₄=0].Rel.γ
System energy efficiency. Fraction of stored energy that becomes sailcraft kinetic energy as measured at the start of the cruise phase. Mission.η
Peak power transmitted by beam director as measured just after leaving beamer primary optic Beamer.Beam.P₃
Pulse duration as measured in the beamer frame Beamer[t₃].Closed.t
Acceleration duration as measured in the beamer frame Beamer[t₃].Closed.tᵦ
Acceleration duration as measured in sailcraft rest frame (proper time) Beamer[t₃].Closed.t₄′
Acceleration distance since t₃=0 Beamer[t₃].Δ
Acceleration at t₃=0 (beam start) Beamer[t₃]
Acceleration at t₄=0 (beam cutoff) Beamer[t₃]
Mean photon pressure felt by sail Sailcraft[T⁺].Substrate.<σ₁₁>
Mean force felt by sail Sailcraft[T⁺].Substrate.F
Mean radiant exitance of the beamer when operating at maximum power Beamer.Beam.<I₃>.kW/m²
Mean radiant exitance of the beamer when operating at t₃=0 (beam start) Beamer[t₃=0].Beam.<I₃>.kW/m²
Mean radiant exitance of the beamer when operating at t₄=0 (beam cutoff) Beamer[t₄=0].Beam.<I₃>.kW/m²
Mean irradiance over sail at maximum allowable sail temperature Sailcraft[T⁺].Substrate.<Iᵦ>.GW/m²
Mean irradiance over sail in its rest frame when operating at t₃=0 (beam start) Beamer[t₃=0].Beam.<I₄′>.GW/m²
Mean irradiance over sail in its rest frame when operating at t₄=0 (beam cutoff) Beamer[t₄=0].Beam.<I₄′>.GW/m²

Associated Models

Lightsail Carrier Satellite [U.S. persons only]:

See also