Orbital Period Calculator
The orbital period is how long a satellite takes to go once around the Earth. Higher orbits are slower and longer: about an hour and a half near the ground, one day at geostationary height.
Standards:
- NGSS HS-ESS1-4
- AP1 Unit 2
- IB D.1
Our alignment; not reviewed by the standards bodies.
The equation
Worked example
- Given
- Altitude above Earth (km): 400 km
- Answer
- Period: 92.56 min
- Period: 1.5427 h
- Orbital speed: 7.669 km/s
- Check
- At 35,786 km the period equals one sidereal day (23.934 h), which is why geostationary satellites seem to stand still; an orbit at 400 km takes about 92.6 minutes. The build checks both.
Assumptions
Circular orbit around a spherical Earth; no drag or J2.
Go deeper
Sources
- H. D. Curtis, Orbital Mechanics for Engineering Students, 4th ed., Butterworth-Heinemann (Elsevier), 2020.
- D. A. Vallado, Fundamentals of Astrodynamics and Applications, 4th ed., Microcosm Press, 2013.
- NASA JPL Solar System Dynamics, planetary physical parameters.