Translate a circular orbit radius into period, revolutions per day, and timing margin against a mission requirement. This early-design tool helps compare candidate orbits before higher-fidelity propagation.
Here, r is orbital radius and μ is the central body's gravitational parameter.
The adjusted period is compared with the maximum period requirement. A positive timing margin means the orbit still meets the requirement after applying the selected design allowance.
Two-body circular-orbit estimate; perturbations and maneuver operations are not included.
At a 6,771 km Earth-centered radius with μ = 398,600.4418 km³/s², the period is about 92.41 minutes. With 5% margin, the adjusted period is about 97.03 minutes, which exceeds a 95-minute maximum.
Enter distance from the body's center. Add the body's mean radius to altitude before using the calculator.
Yes. It uses a two-body circular-orbit approximation unless the page explicitly asks for a mission allowance.
Yes. Replace the gravitational parameter and radius inputs with values for the selected body.
High-fidelity tools may include oblateness, atmospheric drag, third-body gravity, eccentricity, and numerical propagation.
No. They are preliminary engineering estimates and should be checked with validated mission-analysis software.
| Variable | Purpose |
|---|---|
| r | Center-to-spacecraft radius (km) |
| μ | Gravitational parameter (km³/s²) |
| T | Circular orbital period |
| Required period | Maximum accepted mission period |