Teams of three design, program and certify an interplanetary mission. Each specialist owns a station; publish drafts to inform your teammates, run the integrated test, resolve every check, and have all three specialists approve the same revision. Changes clear approvals. Your best certified plan remains on the leaderboard while you iterate.

Scoring: a feasible, fully approved mission earns 1,000 points, plus up to 250 for budget savings, 150 for remaining cruise propellant, and 100 for arriving sooner relative to the mission deadline. An infeasible plan never qualifies to win. The teacher can pause, extend, end, swap lobby assignments, and cover a station after a 45-second disconnect.

Model: coplanar circular planetary orbits, Hohmann or bi-elliptic transfers, spherical gravity and rotation during ascent, exponential air density, drag, staged mass loss and RK4 integration. Parking insertion and space burns are impulsive approximations. The upper stage circularizes at apogee, then is discarded. Cruise propulsion performs departure, optional midpoint burn and capture. No aerobraking, inclinations, gravity assists, structural attitude dynamics, finite-duration space burns or real ephemerides. This is a teaching simulator.

Anyone can join by code without an account or real name. Only verified adults host. Keep your student tab to retain its temporary identity and reconnect. Teams must be complete before launch.

Physics references: NASA rocket equation · Dynamic pressure · Interplanetary trajectories