Orbital Runtime Live
Orbital Simulation
Stateless orbital computation for satellite digital twins. Propagate positions, detect eclipses, compute ground passes, and expand constellation templates — no state, no API keys, just physics.
https://sim.rotastellar.com
Compute, Don't Cache
Orbital state is a function of time and orbital elements. There's nothing to store.
Most satellite APIs cache pre-computed TLE data and return stale positions. The RotaStellar Sim service takes a different approach — it accepts raw orbital elements and computes position, velocity, and eclipse state at any timestamp using SGP4/SDP4 propagation. Every response is computed on-demand, always fresh, always physics-accurate.
Eight Endpoints
Everything you need for orbital digital twins. All stateless, all CORS-enabled, all free.
POST /v1/state
Get position, velocity, and eclipse state at any timestamp for a single satellite.
POST /v1/state/batch
Batch state for up to 100 satellites in a single request.
POST /v1/propagate
Full trajectory over a time window, up to 48 hours. Returns position arrays at configurable step intervals.
POST /v1/passes
Compute ground station visibility windows for any orbit, up to 72 hours ahead.
POST /v1/orbital-params
Compute orbital parameters (period, velocity, RAAN drift) from target altitude.
GET /v1/templates
Pre-built orbit templates: LEO, SSO, MEO, GEO with realistic elements.
GET /v1/constellation-templates
Walker Star, Walker Delta, and custom constellation patterns.
GET /v1/ground-stations
Global ground station network with coordinates, elevation, and capabilities.
Try It Now
No API keys, no signup. Send orbital elements and a timestamp, get back latitude, longitude, altitude, velocity, and eclipse state.
The sim service powers the Live tab in Mission Control's asset detail page, the fleet markers on the monitor globe, and the Operator Agent's orbital position simulation.
Use Cases
- Digital twin satellite positions in real-time
- Ground station pass prediction for contact scheduling
- Eclipse detection for power budget planning
- Constellation design and validation
- Trajectory visualization and analysis
curl -X POST https://sim.rotastellar.com/v1/state \
-H "Content-Type: application/json" \
-d '{
"elements": {
"epoch": "2026-03-01T00:00:00Z",
"mean_motion": 15.5,
"eccentricity": 0.0001,
"inclination": 51.6,
"raan": 200.0,
"arg_perigee": 90.0,
"mean_anomaly": 0.0
},
"timestamp": "2026-03-08T12:00:00Z"
}'
# Response:
{
"lat": 42.3,
"lon": -71.1,
"altitude_km": 408.2,
"velocity_km_s": 7.66,
"in_eclipse": false,
"timestamp": "2026-03-08T12:00:00Z"
}Architecture
The sim service runs on Cloudflare Workers at the edge. No database, no state, no cold starts. Every request computes orbital mechanics from scratch using SGP4/SDP4 propagation. Results are deterministic — same inputs always produce the same output.
This means you can call the sim service from anywhere — your backend, your frontend, a Jupyter notebook, a Rust agent, or a curl command — and get identical, physics-accurate results every time.
Get Started
Simulate before you deploy
Use the sim service to validate orbits, predict passes, and test constellation designs before committing to hardware.