Each target has an approximate round-trip delta-v budget drawn from standard mission-design delta-v maps (LEO → target → Earth return, aerocapture at Earth assumed free). The spacecraft mass needed at each stage follows the Tsiolkovsky rocket equation, applied twice — once for the return burn, once for the outbound burn that must carry that return-leg mass to the target:
m_wet = m_dry · e^(Δv / (Isp·g0)) [Isp = 450 s, g0 = 9.807 m/s²]
m_return-burn = (dry + payload) · e^(Δv_return / ve)
m_LEO = m_launched-to-target · e^(Δv_out / ve)
Mission cost = m_LEO × ($/kg to LEO) [+ $75M ISRU plant if enabled]
Resource value = payload mass × assumed market price ($/kg)
Net profit = Resource value − Mission cost
- Target buttons — switch the delta-v budget and the assumed resource price per kg (lunar water ≈ $10k/kg, C-type volatiles ≈ $3k/kg, M-type platinum-group metals ≈ $45k/kg, Mars ISRU propellant ≈ $8k/kg — all valued against the launch cost they displace).
- Payload slider — how much resource mass the mission returns; it appears on both sides of the ledger (more mass to launch, more mass to sell).
- Launch cost slider — dollars per kilogram to reach LEO, from Starship-class reusable (~$200–500/kg) to expendable heavy-lift (~$10,000/kg).
- ISRU toggle — when on, the return-trip propellant is manufactured at the target instead of launched from Earth, so only the dry spacecraft, payload and a fixed-mass ISRU plant need to leave LEO — at the cost of a one-time $75M plant.
- The delta-v numbers are schematic (not to scale in the view) but the ratios are real: near-Earth asteroids are often cheaper to reach in delta-v than the lunar surface, which is why several proposed missions target them first despite the Moon being physically closer.