terminal-space-program

README

terminal-space-program

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

┌───────────────────────────────────────────────────────────┐
│ terminal-space-program — Sol                              │
│ ┌─────────────────────────────────────┐ ┌───────────────┐ │
│ │    · ·                              │ │ CLOCK         │ │
│ │  ·     ·                            │ │   T+2026-04-23│ │
│ │ ·   ⊙   ·       · ⊕ ·               │ │   warp: 100x  │ │
│ │  ·     ·                            │ │               │ │
│ │    · ·                              │ │ VESSEL        │ │
│ │                                     │ │   LEO-1       │ │
│ │                                     │ │   alt: 200 km │ │
│ └─────────────────────────────────────┘ │   v: 7.78 km/s│ │
│ [q] quit [s] system [m] burn [?] help   └───────────────┘ │
└───────────────────────────────────────────────────────────┘

Install

Latest release: v0.2.0.

# 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.

Build from source

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+ (bubbletea dependency chain).

Keybindings

Key	Action
q, Ctrl+C	Quit
?	Toggle help overlay
Esc	Back / close
→ / l	Next body
← / h	Previous body
s	Switch system (Sol → Alpha Cen → TRAPPIST-1 → Kepler-452)
i	Body info
+ / -	Zoom in / out
f / F	Cycle camera focus forward / backward (system → bodies → craft)
g	Reset camera focus to system
.	Warp up (1× … 100000×)
,	Warp down
0, Space	Pause / resume
m	Open maneuver planner
n	Plan a maneuver node
N	Clear all planned nodes
Tab (in planner)	Cycle direction mode
Enter (in planner)	Commit burn
Esc (in planner)	Cancel burn

Features (v0.2)

Slice-1 of the v0.2 scope — "maneuver planning, closed loop."

• View focus / camera follow. f/F cycles the camera target across the system primary, every body, and the spacecraft (Sol only); g resets to the system view. Focus keeps moving targets centered without refitting the zoom on every frame.
• Maneuver nodes. n plants a node on the current orbit; N clears all pending nodes. Nodes are rendered on-canvas at their projected inertial position and listed in the HUD. When sim-time reaches a node's trigger time, its impulsive burn fires and the node pops.
• SOI-segmented trajectory viz. The predicted post-burn trajectory is partitioned by dominant sphere-of-influence. Samples inside the craft's home SOI render stride-2 dashed; samples that cross into a foreign SOI render stride-1 solid so capture arcs read visually distinct from cruise.
• Hohmann preview HUD. When the cursor-selected body has orbital data, the SELECTED block renders reference heliocentric Δv1 / Δv2 / transfer time computed off the system primary's GM and the craft's current inertial radius. Earth → Mars lands within 10% of the Curtis §6.2 textbook values.

Features (v0.1)

• Viewer. Physically-plausible renderings of Sol, Alpha Centauri, TRAPPIST-1, and Kepler-452. Planets move under time warp; orbit lines drawn from the same Kepler math that places the planets.
• Spacecraft. One vessel in low Earth orbit, propagated with velocity-Verlet on a patched-conic two-body model. Energy-conservation verified under 1% drift across 1000 orbits (we ship at ~1e-7%).
• Burns. Impulsive burns with prograde / retrograde / normal± / radial± modes, rocket-equation fuel accounting, and live shadow- trajectory preview in the maneuver planner.
• Time warp. Six discrete steps (1× → 100000×) with integrator- aware clamping so sim-time can't outrun numerical stability.
• Single binary. 5-target GoReleaser matrix (linux+darwin amd64/arm64, windows amd64), CGO_ENABLED=0, -ldflags "-s -w".

Deferred to v0.3+

Finite-duration burns (impulsive only through v0.2), Lambert targeting with auto-plant nodes in the correct SOI frame, multi-system spacecraft, save/load, N-body perturbations, config-file custom systems, mouse support.

Implementation plan

Full design doc: docs/plan.md. Summary:

• 4-phase physics progression (viewer → Verlet propagation → impulsive burns → maneuver library).
• Bubble Tea root model with screen-level sub-models (orbit / bodyinfo / maneuver / help).
• GoReleaser single-workflow CI; release artifacts on tag push.

Credits

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

License

MIT. See LICENSE.