I have been working with spreadsheets to estimate the mass and performance of spacecraft in the Sublight Universe. But over time, those spreadsheets have become increasingly hard to maintain. Also, being Microsoft Excel, strange things happen when I'm not looking at them.

After having yet another starship go pumpkin, I have decided to formalize my starship performance estimator into an easy-to-use browser application.

Rocket equations are pretty complicated. So before we start fiddling with exponets and running non-linear equations backwards, we should nail down all of the details that we don't intend to change. Ships are build for a purpose, and that purpose takes precedence over every other consideration.

Gross statistics for the vessel

A name for this project Total Mass of vehicle at launch (m0) project_name tons vehicle_wet_mass mt vehicle_dry_mass mt vehicle_propellent_mass mt vehicle_mass_empty mt vehicle_volume m3 vehicle_compliment

# Vehicle Design

Mission Calculation Details

If this is a science or reconnaissance mission, what sort of equipment are you dragging along, and how long will you be observing/patrolling/spying? Does you ship carry cargo?

When estimating tonnage, here are some figures:

 Mass (kg) Mass (mt)metric tons Reference object 16000 16 a greyhound bus 36000 36 a fully loaded semi-truck 80000 80 a fully loaded Boeing 737-800 450000 450 a fully loaded Boeing 747-8 2.8e+06 2800 a saturn V rocket 4e+06 4000 a modern naval frigate 9.5e+06 9500 a modern naval destroyer 5e+07 50000 a cruise ship 1e+08 100000 an aircraft carrier 3.5e+08 350000 the Empire State Building 8e+08 800000 the Pentagon 6e+09 6000000 Hoover Dam 1.21e+16 12100000000000 Lake Superior (the water at least)
Mission Equipment Mass Mission Equipment Volume mission_equipment_mass kg mission_equipment_volume m3 mission_manned_volume m3 mission_equipment_rho kg/m3 mission_equipment_constant_power kwh/day mission_equipment_mission_power kwh/day mission_mass_cargo kg mission_volume_cargo m3 mission_cargo_rho kg/m3 mission_cargo_constant_power kwh/day

How many people are going to be along for the voyage?

Crew Calculation Details
Number of souls aboard Outer radius of rotational habitat souls_aboard people rotational_radius m rotational_gravity G survival_endurance days waste_endurance days vehicle_endurace days habitat_volume_per_capita m3 habitat_furnishings_estimate kg/m3 waste_water_recycle_factor 0.0-1.0 eject_trash incinerate_trash potable_propellent total_accommodation_volume m3 total_accommodation_mass kg accommodation_mass_potable_water kg accommodation_provision_mass kg accommodation_solid_waste_per_day kg/day accommodation_water_waste_per_day kg/day accommodation_power_daily_kwh kwh/day

Here is where we spec out the reactor and engines to use

Reactor Calculation Details

Putting in the reactor, engines, and other fun stuff

We are playing a guessing game with physics. The heavier our space craft is, the more engine we will need to get it up to the speed we want it to go. But the curves on those equations are not-exactly easy to estimate. So we start with a guess, solve the equation, and then keep refining our guess until the calculated mass of the ship matches our hunch.

Estimate of structural mass per unit volume required. (Steel ship construction: 173 kg/m3) Design estimate of the mass of the vehicle, minus propellent structural_density tons vehicle_dry_mass_estimate kg design_accelleration m/s2 design_thrust N power_reactor_wall_density kg/m3 power_reactor_wall_thickness m power_reactor_wall_youngs_modulus Pa power_reactor_wall_yield_stress Pa power_reactor_wall_safety_factor power_mass_reactor kg power_thermonuclear_pellet kg power_thermonuclear_duration s power_reactor_inner_radius m vessel_engineering_volume m3 vessel_engineering_mass kg voyage_fusion_fuel kg power_storage kwh velocity_exhaust m/s propellent_efficiency kg/s reactor_efficiency kg/s engine_count propellent_flow_rate kg/s

# Voyage Design

Quick guide to rocket science
Distance of mission DeltaV for the first leg of the trip departure_distance au departure_deltav m/s cargo_departure_mass kg departure_booster_deltav m/s return_distance au return_deltav m/s cargo_return_mass kg mission_loiter_days days mission_loiter_deltav m/s