alpha21: Simple patched-conics estimator with Mission 1–10 cases, Orion as the Mission 7 no-depot direct-entry case, restored OG Earth-surface return, MLI7/MLI11 boiloff classes, white-tile and OG comparison variants, aerobrake-only heatshield validation, depot-deployment cases, and Stubby deleted-ring dry-mass savings with 100% tankage allowance.

Basic Instructions: The simplest use is to explore pre-selected missions under "Mission Profile" and then customize those missions by adjusting either payload and clicking "Calc fuel" or fuel load and clicking "Calc max payload".

This is mostly EOR, although there is a mission to boost fuel to NRHO.The assumption being that with fuel near to the Moon, many formerly impossible missions become possible, such as manned propulsive return to LEO. It's also interesting to try things you know won't work and see how badly they fail.

Missions have been reorganized so that they have a primary Mission number, and a suffix designation based on the type of Starship used: OG black tile (BT), white tile (WT), MLI, or Stubby-MLI (St). MLI in this version has been adjusted to use more robust standoffs that should survive winds aloft, but unfortunately suffer from an increased thermal leakage. "Stubby Starship" has been fixed so that it supports ring section delete between tanks and nose, likely the simplest way to get to a low-mass Starship. One-way missions from LEO are still very attractive, and I suspect that cargo's what Starship will initially be used for.

You can see that the round-trip missions using propulsive capture to LEO are all infeasible due to the heavy fuel requirements. Based off this separate calculator, I'm guesstimating that a hypothetical heat-shielded version of HLS could aerobrake into a 350km LEO parking orbit for 15 tons of reserve fuel, or less. It depends on factors like heat shield soak and fatigue and how impatient you are. At ~5 days of aerobraking it looks theoretically possible to bring a Starship back to earth with people in it, coming in at high inclination >60deg (radiation belt avoidance), and then doing a aerobraking plane change down to the 30 degrees of Canaveral/Boca Chica. With a great deal of fuel, you can make a direct descent through the belts and then aerobrake the rest.

There are always two types of Starships involved: the Lunar HLS (either BT, WT, MLI, or Stubby) and the Refueling Tanker. Their specifications can be adjusted in dedicated panels below. The two main types of HLS are MLI vs white-tile covered (currently 100% tile). Only the tile versions can aerobrake. Note that tankers can be either expendable or reusable. Expendable cuts the total number of refueling flights significantly at the cost of 6 very expensive Raptor engines. There is no separate propellant depot because my suspicion is that at the beginning HLS will be the propellant depot, and that Orion or Dragon will fly up to dock with it.

There is now a per-segment boiloff model (disabled by default). MLI7 and MLI11 tile classes use the newest low-boiloff estimates; white-tile and OG black-tile classes remain high-boiloff comparison reference cases. Note that boiloff during aerobraking is a complete SWAG, LLO is estimated at half of LEO boiloff. MLI and Stubby vehicles have neither heat shields nor flaps, so aerobraking missions only work for white-tile and OG black-tile variants. The MLI tiles as designed will not survive on the nose of Starship unprotected, so all MLI7/11 models are assuming an AZ93-coated nose with internal MLI-equivalent insulation. That also implies a thermal break between nose and main body. None of this has been disclosed or discussed by SpaceX to date, SFAIK.

All models are as simple as possible with the goal of giving a qualitative feel for tradeoffs without being numerically dependable. There are too many assumptions, estimations, and outright SWAGs for this tool to do that. Expect real payloads to be less and refueling flights at least one greater in number. Do not base your space program on a web tool!

Mission payload and fuel

Mission profile

Mission summary

Mission Starship — Moon-bound vehicle

Refueling Starship — tanker fleet specs

Super Heavy — separation context

Orion Capsule

Δv budgets

Propulsion and logistics

Applied to lunar mission burn legs only; tanker insertion uses the Super Heavy gravity + steering loss field.

Boiloff and coast times

Rates are absolute heat-driven losses, not percent-of-tank.

Logistics snapshot

# Leg Engine Δv Docked Orion Mission Starship mass before Minimum prop before Prop burned Prop after burn Boiled off after coast Prop after coast

Notes

  1. Model limitations. This is a first-order rocket-equation planner. Optional boiloff is a lumped end-of-coast subtraction in tons/day, with aerobraking-orbit exposure modeled as its own regime; lunar mission legs still omit gravity losses, plane changes, cooldown, settling, residuals, thermal limits, and operational reserves unless the user adds them through Δv, margin, or boiloff inputs.
  2. Mass accounting. The default Lunar Mission Starship dry mass is the no-heat-shield/no-flaps baseline. Aerobraking returns require the heat-shielded HLS flavor (+10 t), and replace the propulsive LEO-capture leg with aerobraking to a 350 km parking orbit, which requires aerobrake return reserve fuel (default: 15 t, editable). In earlier versions of this tool, there was an Earth-surface-return mission that needed the OG Starship with heat shield, flaps, and landing legs (+25 t dry mass) plus +20 t terminal landing fuel.
  3. Stubby tankage. The Stubby model assumes the vehicle keeps Starship's 9 m diameter and is shortened by deleting tank barrel length. Using a 52 m Starship height basis with a 16 m fixed nose and 36 m body/skirt tank-bearing section, the Stubby model deletes 0–8 rings. Each deleted ring removes 1.8 m of body/skirt and saves 1.6 t of dry mass. At the default 8-ring deletion, dry mass is 67.2 t.
  4. Refueling tanker accounting. Tanker flights are modeled as zero-cargo launches. The planner separately computes reusable residual propellant in LEO and expendable residual propellant in LEO using the selected ground-relative staging velocity plus eastward launch-site rotation, staging altitude, dry mass, propellant load, Raptor Isp, and explicit gravity/steering loss. Reusable mode then subtracts the landing reserve; expendable mode uses the lower dry mass and has no landing reserve subtraction. Ullage allowances are not included unless the user adds margin.