Earth Orbit Calculator
Calculate orbital speed and period for satellites at any altitude around Earth
Calculate Orbital Parameters
Height above Earth's surface (0 km = sea level)
Orbital Parameters
Additional Parameters
Alternative Units
Orbital Speed Formula: v = √(GM/(R+h))
Orbital Period Formula: T = 2π√((R+h)³/GM)
Calculation: √(6.674e-11 × 5.972e+24 / 6.771e+6) = 7672 m/s
Orbit Classification: Low Earth Orbit (LEO)
Orbital Mechanics Insights
Example: ISS Orbit
Given Parameters
Altitude: 408 km
Earth's radius: 6,371 km
Earth's mass: 5.97×10²⁴ kg
G: 6.67×10⁻¹¹ m³/kg⋅s²
Calculation
Orbital radius = 6,371 + 408 = 6,779 km
v = √(GM/r) = √(3.99×10¹⁴/6.779×10⁶)
v = √(5.88×10⁷) = 7,667 m/s
ISS orbital speed ≈ 7.67 km/s
Orbital period ≈ 92.7 minutes
Orbital Classifications
Low Earth Orbit (LEO)
200-2,000 km: ISS, satellites
Medium Earth Orbit (MEO)
2,000-35,786 km: GPS, navigation
Geostationary Orbit (GEO)
35,786 km: Communications, weather
High Earth Orbit (HEO)
>35,786 km: Scientific missions
Orbital Facts
ISS travels at 27,600 km/h (17,150 mph)
Lower orbits are faster than higher orbits
Geostationary satellites appear stationary
Orbital speed decreases with altitude
Moon orbits at ~384,400 km altitude
Understanding Earth Orbits and Satellite Motion
Orbital Mechanics Principles
Satellites remain in orbit by traveling fast enough that their centrifugal force balances Earth's gravitational pull. The faster they travel, the higher they can orbit. This delicate balance creates stable circular orbits at specific altitudes.
Why Speed Decreases with Altitude
Counterintuitively, satellites at higher altitudes travel slower than those closer to Earth. This is because gravity weakens with distance, so less speed is needed to maintain orbit. The ISS at 400 km travels much faster than geostationary satellites at 35,786 km.
Kepler's Laws in Action
Satellite orbits follow Kepler's laws of planetary motion. The square of the orbital period is proportional to the cube of the orbital radius. This mathematical relationship allows us to predict orbital characteristics with high precision.
Orbital Speed Formula
v = √(GM/(R + h))
- v: Orbital speed (m/s)
- G: Gravitational constant (6.674×10⁻¹¹ m³/kg⋅s²)
- M: Earth's mass (5.972×10²⁴ kg)
- R: Earth's radius (6.371×10⁶ m)
- h: Altitude above surface (m)
Orbital Period Formula
T = 2π√((R + h)³/GM)
The orbital period (T) is the time required to complete one full orbit around Earth. It increases with altitude, meaning higher satellites take longer to orbit Earth.
Low Earth Orbit (LEO)
- • International Space Station
- • Earth observation satellites
- • Starlink internet constellation
- • Hubble Space Telescope
- • Weather monitoring
- • High-resolution imaging
Medium Earth Orbit (MEO)
- • GPS satellites (NAVSTAR)
- • GLONASS navigation
- • Galileo positioning
- • Navigation constellations
- • Some communication satellites
- • Scientific missions
Geostationary Orbit (GEO)
- • Communication satellites
- • Television broadcasting
- • Weather satellites
- • Internet backbone
- • Military communications
- • Appears stationary from Earth