Satellite Orbital Period Calculator
Calculate orbital period and speed for Earth satellites.
Enter altitude and get period in minutes, velocity in km/s, and orbit classification (LEO/MEO/GEO/HEO).
Satellite Orbit
Earth satellites orbit at a range of altitudes, each with different periods and velocities.
Orbital period formula:
T = 2π √(a³ / GM_Earth)
Where a = R_Earth + h (Earth’s radius plus orbital altitude).
Orbital velocity:
v = √(GM_Earth / a)
Constants:
- G = 6.674 × 10⁻¹¹ N·m²/kg²
- M_Earth = 5.972 × 10²⁴ kg
- R_Earth = 6,371 km
Orbit classifications:
- LEO (Low Earth Orbit): 160–2,000 km — T ≈ 88–127 min, v ≈ 7.8–7.1 km/s
- ISS: 408 km, T ≈ 92.6 min, v ≈ 7.67 km/s
- Hubble Space Telescope: 540 km, T ≈ 95 min
- MEO (Medium Earth Orbit): 2,000–35,786 km
- GPS satellites: ~20,200 km, T ≈ 12 hours
- GEO (Geostationary Earth Orbit): 35,786 km — T = 24 hours exactly
- Communications satellites appear stationary in the sky
- HEO (Highly Elliptical Orbit): highly elongated orbits (e.g., Molniya orbits for high-latitude coverage)
GEO derivation: Setting T = 86,400 s and solving for a: a = (GM T²/4π²)^(1/3) = 42,164 km from Earth’s center, or 35,786 km altitude.
First orbital satellite: Sputnik 1 (1957): 215 km perigee, 939 km apogee, period 96.2 minutes, orbital speed ~7.9 km/s.