Orbital Period
Explore orbital time, speed and the physics behind every revolution.
Calculation & assumptions
Circular orbit · Spherical central body · Negligible satellite mass
R + h : Orbital radius = 6,771 km
μ : Gravitational parameter = 398,600.4418 km³/s²
T is the period; v is the constant circular-orbit speed. This is not an escape trajectory or a stability assessment.
Orbital Dynamics
1 h 32 min
Playback is accelerated 300×. It is a circular orbit shown in perspective.
How altitude changes an orbit
A higher altitude increases the orbital radius, which results in a longer orbital period and a lower orbital speed. Lower orbits complete more revolutions per day and have higher orbital speeds.
Worked example
Earth · 400 km altituder = 6,371 + 400 = 6,771 km
T ≈ 5,545 s ≈ 92.4 min
v ≈ 7.67 km/s
Using the mean Earth radius and conventional Earth gravitational parameter. Rounding is for display only.Why orbital speed changes
An elliptical orbit, viewed from above. Gravity pulls more strongly near the central body.
Illustrative ellipse, not the circular orbit calculated above. On a circular orbit, speed stays constant.
Frequently asked questions
What is orbital period?
The orbital period is the time required for one complete revolution. Here the satellite is assumed to have negligible mass and to follow a circular orbit around a spherical central body.
Why does a higher orbit take longer?
A higher orbit has a longer path and a lower circular-orbit speed. In this model the period scales with orbital radius to the power 3/2.
Is the visualizer a live satellite tracker?
No. The scene is an illustrative, accelerated simulation driven by the entered values. It does not use live ephemerides, predict satellite locations, or establish whether a real orbit is safe or stable.
Does the ellipse in the teaching diagram change the calculation?
No. The separate Kepler diagram shows equal swept areas on an elliptical orbit. The calculator and main simulation remain circular; the apparent ellipse in the main scene is a perspective view of a circle.
What does this calculator estimate?
It estimates the time needed to complete one circular orbit.
Is this an exact mission-planning tool?
No. It is an educational calculator based on the stated constants and simplified assumptions.
How accurate is the result?
It assumes a two-body circular orbit and ignores perturbations, drag and oblateness.
Sources & References
NASA — Gravity & MechanicsOrbital motion and Kepler’s laws.
JPL — Astrodynamic ParametersGravitational parameters and constants.References do not imply institutional endorsement. Preset radii: JPL planetary physical parameters and NASA mean-radius fact sheets.
Continue exploring Space
Explore orbital time, speed and the physics behind every revolution.