Stage 1 / Mission plan
Stage 1: the mission plan
Four rungs, a bench relay breadboard and a pre-flight gate, each with a numeric pass/fail metric, a cost band, and a timeline. Hardware and launch by category, they sum to $17–28M; $22–36M with a 30% reserve on those bands; program-level staff, operations and integration are not yet estimated. $25M is the planning figure and the first tranche, released rung by rung. Four to five years with Rungs 1 and 2 overlapping, five to seven if strictly sequential. First measured data in the lab for under $1.5M; first flight data at about $2.5–5.5M, about two years in.
01 / The rungs
The ladder.
A sail under a beam, in vacuum.
- Setup
- A university vacuum chamber, a 1 kW fibre laser at 1070 nm with a ~2–3 mm spot, a cm-scale silicon-nitride sail sample on a torsion balance, an IR camera and a photodiode (a 10 kW source, the stretch goal, covers about a third of a square centimetre at 0.3 GW/m²).
- What it proves
- A silicon-nitride sail survives rail-class intensity in vacuum for a sustained period, and holds its shape.
- Success metric
- Survives ≥60 s at ≥0.3 GW/m² in vacuum. Reflectance ≥95% at 1070 nm, with absorptance measured by laser calorimetry at parts-per-million resolution — at rail intensity a sail can only tolerate tens to hundreds of ppm of absorption — and transmittance measured separately, and reflectance measured across 1070–1190 nm (the band a sail receding at 10% of light speed sees) and across the solar spectrum. Force within 20% of the value those measurements predict. Buckling onset and shape change measured against a stated flatness limit for Rung 2.
- Data handed to the next rung
- Intensity and duration envelope; measured absorptance and emissivity; shape stability under a Gaussian spot.
- Cost
- $0.5–1.5M
- Timeline
- 6–12 months
A relay on the bench.
- Setup
- A metre-class membrane optic refocuses a 1 kW beam it did not generate onto a target at range; throughput and wavefront measured.
- What it proves
- The operation the full rail repeats ~27 times, at bench scale. Gives Stage 2 a measured per-relay efficiency and a relay technology to fly.
- Cost
- $0.5–1.5M
- Timeline
- 9–15 months, alongside Rung 0.
A blind thrust-recovery test.
- Gate before any Rung 2 hardware is ordered
- A demonstration that the sail's sensors and ranging can recover a known thrust to a stated confidence, and a model of the spinning sail built from Rung 0 data.
Pointing at range, no sail.
- Setup
- One 12U cubesat holds a 1–10 W laser on a released, drifting target carrying both a retroreflector and the Rung 2 sail beacon, at 5–10 km.
- What it proves
- Holds a laser on a beacon-equipped passive target at 5–10 km to ≤10 µrad rms per axis. 100 km is a stretch objective nothing depends on. This sets the pointing budget Rung 2 needs.
- Success metric
- On target ≥90% of a pass at 5–10 km against the beacon. Jitter ≤10 µrad rms per axis. Cold acquisition under 60 s. (100 km is a stretch objective nothing downstream depends on.)
- Data handed to the next rung
- Beam-holding range and jitter; acquisition time.
- Cost
- $2–4M
- Timeline
- 18–24 months
Cooperative laser crosslinks at 100+ km are proven. What transfers to Rung 2 is the pointing loop — jitter, acquisition, tracking a drifting target — not a corner cube's optical signature, which is why the target also carries the sail's beacon.
First laser push of a free-flying sail in space.
- Setup
- ESPA-class smallsat (~150 kg, station-keeping propulsion), 1 kW fibre laser through a 20 cm aperture at 5–10 km, 9-minute battery bursts in Earth's shadow; ~450–500 W orbit-average bus. Spin-stabilised 10 g sailcraft (10–30 rpm), 30 cm square sail, with an optical beacon for the pusher's tracker and photodiodes on the sail that measure how much of the beam it intercepts. Pointing ≤10 µrad rms per axis. 0.2–0.35 m/s per burst at about 95% interception at 5 km and about 70% at 10 km, measured on the sail, not assumed (projection).
- What it proves
- Measured thrust on a sail in space. Never demonstrated in any published experiment.
- Success metric
- ≥10 bursts within 30% of prediction, using intercepted power measured on the sail and the reflectance and absorptance measured in Rung 0. Laser-off intervals show no laser-correlated force. Thrust per intercepted watt at least 85% of the value Rung 0's measurements predict.
- Data handed to the next rung
- Thrust per intercepted watt in space; sail attitude behaviour under beam; the estimator.
- Cost
- $8–12M
- Timeline
- 2–3 years
Why 5–10 km: at 15 km, 10 µrad of jitter puts only about 40% of the beam on a 30 cm sail; at 5–10 km it is 70–95%.
Handoff.
- Setup
- The second station about 5 km along-track, so the first station stays inside its tested 5–10 km range through the handoff. Sail released from A, pushed past B; B acquires while A is still firing, then A cuts.
- What it proves
- That one emitter can hand a sail to another emitter with no gap in push: acquisition of a sail already under beam, and the sail's response to a change of source. Not tested here: the passive relay optics the full rail is mostly made of.
- Success metric
- ≥5 handoffs. B locked before A's cutoff. Signed along-track Δv within 20% of a prediction posted before each burst.
- Data handed to the next rung
- Handoff overlap requirement and re-acquisition behaviour — the numbers that size station spacing. Handed to Stage 2.
- Cost
- $6–9M
- Cost note
- Assumes the Rung 2 pusher is reused as station A; the Rung 2 bus is built for it.
- Timeline
- +12–18 months
Passive relay optics are not tested in Stage 1 — see Risks.
02 / Cost and launches
What Stage 1 costs.
Stage 1 is three launches: one rideshare slot each for Rungs 1, 2 and 3.
03 / Partner with us
Partner with us.
We are raising $25M for Stage 1 from investors and philanthropic funders who want to see the first laser push of a sail in space, and the first handoff, measured and published. First flight data at about $2.5–5.5M.