Terminal-native orbital-mechanics rocket simulator. A take on Kerbal Space Program that lives in your terminal, distributed as a single static Go binary.

I love Kerbal Space Program, I love TUI Applications. I decided the two should be married for when I'm bored and have a terminal available.

By default, you spawn in an Apollo-style SIV-B in a 500km circular orbit. Switch targets to Moon (press t to switch and T to clear). Plant a Hohmann transfer + inclination change (press H). Or, fly it all manually. See Controls & flight guide for a quick tour, a launch walkthrough, and the full list of keys.

Plan transfers between planets and moons, fly your rocket off the pad and into orbit by hand, rendezvous and dock, stage away spent boosters, and bring a capsule home under parachute — all drawn with braille-canvas graphics and driven from the keyboard. No mouse required, no GUI, just a single binary in your terminal.

Under the hood it's a real orbital-mechanics sim: gravity, fuel, atmospheric drag, and timing all matter, the way they do in real life. Unlike KSP (without mods), the default game renders our solar system. Launches are hard, they take 7.5km/s for LEO - just like real life. The moon is inclined, the earth is tilted on its axis. To match the real solar systems, there are real life vessels with accurate loadouts of thrust.

Recently introduced: a familiar 1/10th-scale system named Lumen; home to a familiar planet, Kernel, with two moons, Cursor and Glyph - and a nearby red planet, Rust. A Lumen-specific vessel is scaled to that environment. It's a little rough appearance-wise as no textures have ported over to that system, but vessels fly and hit familiar Delta-V marks for launch, Cursor (Mun) transfers, etc. From a default game launch press TAB to cycle through the available solar systems until you reach Lumen. Press F to cycle to the planet Kernel, then press N to spawn a craft there.

Each vessel is bound for its lifetime to the system it spawns in — the simulator flies every vessel against its own system and the camera follows your active vessel's system, so a craft parked in Sol keeps orbiting while you fly in Lumen (TAB stays a browse-only camera toggle). Adding Lumen also changed the body catalog, so the on-disk save format moved to v8; older saves auto-migrate on load.

When your live trajectory is heading into a body's sphere of influence, the orbit map draws the full encounter arc ahead of arrival — entry, perilune, and exit — with a Perilune ⊕ marker and an always-on SOI PASS chip showing the altitude and time to closest approach. No need to target the body first. Every orbital marker (apoapsis, periapsis, nodes, closest approach, maneuver nodes) is now a single colored glyph: shape is type, color is type, brightness is state (nominal / counterfactual / alarm). To read an encounter up close, press f to focus the body it passes — the camera fits to the body's sphere of influence so the capture curve fills the canvas, and from there the view is yours: +/- zoom holds until you change focus, view, or system.

Recently introduced: an in-game Vehicle Assembly Building (VAB). From the main view press Esc → [Build (VAB)] to design your own rocket from fine parts — compose engines, fuel tanks, command cores, antennas, and structure into stages, stack the stages, mark dock seams for nose payloads, and watch a live Δv / TWR / mass readout as you build. Save a design and it shows up in the spawn form (n) alongside the built-in craft, so you design once and launch many. Designs are portable files under ~/.config/terminal-space-program/designs/ (KSP .craft-style); drop one into the sibling loadouts/ overlay dir to share it as a mod. Multiple engines in a stage combine honestly (thrust adds, Isp is the thrust-weighted blend) and a stage holds a single fuel chemistry, so everything you build flies on the same honest physics as the shipped fleet.

The visual foundation was lifted (with MIT attribution) from furan917/go-solar-system. See NOTICE.md for the full acknowledgments list.

brew install --cask jasonfen/tap/terminal-space-program

scoop bucket add jasonfen https://github.com/jasonfen/scoop-bucket
scoop install terminal-space-program

# Linux x86_64
curl -L https://github.com/jasonfen/terminal-space-program/releases/latest/download/terminal-space-program-linux-amd64.tar.gz | tar xz
./terminal-space-program

Replace linux-amd64 with linux-arm64, darwin-amd64, darwin-arm64, or windows-amd64 (use the .zip variant on Windows).

No Go toolchain, no libc dance. CGO_ENABLED=0 static binaries.

git clone https://github.com/jasonfen/terminal-space-program
cd terminal-space-program
go build ./cmd/terminal-space-program
./terminal-space-program

Requires Go 1.24 or newer.

By default the game opens with a vessel in low Earth orbit. Flags let you jump straight to a different start — a system, a body to orbit or launch from, an orbit altitude and inclination, or a named launch site:

terminal-space-program --orbit moon --altitude 100km          # 100 km lunar orbit
terminal-space-program --system Lumen --orbit kern --loadout Kern-Stack
terminal-space-program --orbit earth --altitude 400km --inclination 51.6
terminal-space-program --launch-site KSC --loadout Saturn-V    # on the pad
terminal-space-program --list-bodies --system Lumen           # discover names
terminal-space-program --version

--version and the --list-* discovery flags print and exit. See the command-line reference for every flag, units, defaults, and more examples.

Vehicle loadouts and stage parts are data, not code. Drop a .json file in ~/.config/terminal-space-program/loadouts/ (or under $XDG_CONFIG_HOME) to add your own loadouts and parts, or override a built-in by reusing its id. A loadout is an ordered list of part references; a part is one atomic stage. Run terminal-space-program --list-loadouts to see the merged catalog and confirm yours loaded — a malformed file is skipped with a warning, never failing the rest. See the command-line reference for the format.

• Controls & flight guide — a quick tour, a launch walkthrough, and the full list of keys.
• Constellation deployment — dropping an evenly-spaced ring of comsats from one carrier, and the phasing-orbit math that makes it cheap.
• Command-line reference — every startup flag with examples.
• Version history — what landed in each release.

MIT. See LICENSE.