How Fast Do Satellites Move? Speed of Satellites in Orbit

Quick answer: How fast do satellites move? In low Earth orbit, satellites move at about 7.5 to 7.8 km/s, roughly 27,000 to 28,000 km/h (17,000 to 17,500 mph), and circle the planet every 90 to 100 minutes. Starlink satellites travel at about 27,400 km/h, the International Space Station at 27,600 km/h, GPS satellites at 13,900 km/h and geostationary satellites at 11,070 km/h (6,880 mph). The rule is simple: the higher a satellite orbits, the slower it moves.

A satellite's speed is set almost entirely by one number: its height above Earth. This guide gives the speed of satellites in every orbit, compares well-known spacecraft such as Starlink, the ISS, Landsat and GPS, and shows the formula behind every figure, so you can work out how fast any orbiting satellite is moving yourself. All speeds below are calculated from orbital physics and checked against NASA, ESA and operator data.

An Earth observation satellite in low Earth orbit travels at about 27,000 km/h, fast enough to circle the planet in roughly an hour and a half.

How Fast Does a Satellite Orbit the Earth?

How fast a satellite travels depends on its orbit. Close to Earth, gravity is stronger, so a satellite has to move faster to keep from falling back. Farther out, gravity is weaker and the required satellite speed in orbit drops. Here is how fast satellites are moving in each main orbit:

Speeds are for circular orbits and measured relative to Earth's centre. A satellite never needs an engine to hold this speed: once it reaches orbit, it coasts, and only small thruster burns are needed to correct drift. Geostationary and geosynchronous are not quite the same: both take 23 hours 56 minutes per orbit, but only a geostationary satellite sits over the equator and appears fixed in the sky. A geosynchronous satellite on a tilted orbit traces a figure-eight over the course of each day.

Satellites in low, medium and geostationary orbits share the sky but move at very different speeds: the closer to Earth, the faster the orbit.

Speed of Satellites: Well-Known Satellites Compared

These are the current speeds of satellites people search for most, calculated from each one's typical operating altitude.

How Fast Do Starlink Satellites Travel?

Starlink satellites travel at about 7.6 km/s, roughly 27,300 to 27,450 km/h (about 17,000 mph). That is the orbital speed for their working altitudes of about 480 to 570 km. Each Starlink satellite circles Earth in about 94 to 96 minutes, or roughly 15 times a day.

SpaceX is moving roughly 4,400 Starlink satellites from the 550 km shell down to about 480 km. At the lower altitude they move about 150 km/h faster and complete each orbit about a minute and a half sooner. The bigger benefit is safety: atmospheric drag is stronger lower down, so a failed satellite falls back and burns up much sooner instead of drifting for years. More than 11,000 Starlink satellites are now in orbit, around two thirds of all active satellites.

Right after a launch, a batch of Starlink satellites can be seen as a "train" of bright dots moving across the sky in a line. They are all moving at the same orbital speed, then spread out and raise their orbits over the following weeks, after which they become much harder to see.

How Fast Is the ISS Moving?

The International Space Station moves at about 7.66 km/s, or 27,600 km/h (17,100 mph), at an altitude of roughly 415 km. One lap of the planet takes about 93 minutes, so the crew sees about 15 or 16 sunrises and sunsets every day. The point on the ground directly below the station crosses the continental United States in about 10 minutes.

Thin air at that height slowly drags the station down, so thrusters on visiting spacecraft periodically reboost it. NASA plans to retire the ISS at the end of this decade using a SpaceX-built deorbit vehicle. The commercial space stations planned to replace it will fly at similar altitudes, so they will also travel at about 27,500 km/h.

Why Do Satellites Move So Fast?

Two forces are in balance. Gravity pulls the satellite toward Earth, while its inertia, the tendency to keep moving in a straight line, carries it sideways. The result is a constant fall in which Earth's surface curves away beneath the satellite at the same rate it drops, so it never gets closer. Isaac Newton described this with his cannonball thought experiment: fire a cannonball fast enough horizontally from a high mountain and it would fall all the way around the planet instead of landing.

Near the surface, that sideways speed is about 7.9 km/s. At 400 km it is about 7.7 km/s. Gravity has not disappeared up there: at the altitude of the ISS it is still about 90 percent as strong as on the ground. Astronauts float because they and their station are falling together, not because there is no gravity.

Satellite Speed Formula: How to Calculate Orbital Velocity

For a circular orbit, the speed of a satellite depends only on Earth's mass and the satellite's distance from Earth's centre:

v = √(GM ÷ r), where GM is Earth's gravitational parameter (398,600 km³/s²) and r is Earth's radius (6,378 km) plus the satellite's altitude.

1. ISS example: r = 6,378 + 415 = 6,793 km. 398,600 ÷ 6,793 = 58.68, and the square root is 7.66 km/s. Multiply by 3,600 to get 27,580 km/h.
2. Time per orbit: T = 2πr ÷ v = 42,681 km ÷ 7.66 km/s = 5,572 seconds, about 92.9 minutes.
3. Geostationary check: r = 42,164 km, so one orbit is 264,925 km long. Dividing by 23.93 hours gives 11,070 km/h, the speed that keeps the satellite above the same point on the equator.

The satellite's own mass is not in the formula. A 420-tonne space station and a 1 kg CubeSat at the same altitude move at exactly the same speed.

Why Higher Satellites Move Slower

Orbital speed falls with the square root of distance from Earth's centre. GPS satellites orbit about four times farther from the centre than the ISS, so they move at about half its speed. The orbit also gets much longer, so the time for one lap grows even faster: about 93 minutes for the ISS, 12 hours for GPS and almost 24 hours in geostationary orbit. Reaching a higher orbit still takes more rocket energy, even though the satellite ends up moving slower once it gets there.

Satellite Speed in Elliptical Orbits

Not every orbiting satellite moves at a constant speed. On an elliptical orbit, a satellite speeds up as it swings close to Earth and slows down at its farthest point, sweeping out equal areas in equal times as Kepler's second law describes. A Molniya-type orbit reaches about 36,200 km/h at its low point and slows to about 5,400 km/h at its high point. NASA's TESS planet-hunting telescope, on a very wide orbit that reaches out near the Moon's distance, moves at about 8,600 km/h at its closest approach and about 2,500 km/h at its farthest.

Satellite Speed Compared with Escape Velocity, Planes and Bullets

A rocket has to reach about 28,000 km/h (17,500 mph) to place a satellite in low Earth orbit, while escaping Earth's gravity entirely takes about 40,000 km/h (25,000 mph). Here is how a typical low Earth orbit satellite compares with other speeds:

What Changes a Satellite's Speed Over Time?

• Atmospheric drag: in low orbits, traces of air steal energy. The satellite sinks, and because it is now lower it actually speeds up. Drag rises sharply when solar activity heats and expands the upper atmosphere, which is why Hubble has dropped below 500 km and could re-enter later this decade without a boost.
• Station-keeping burns: operators fire small thrusters to correct the pull of the Sun, the Moon and Earth's slightly flattened shape, and to dodge debris.
• Orbit changes: a burn in the direction of travel raises the orbit, and the satellite ends up slower. A burn against the direction of travel lowers it, and the satellite ends up faster.
• End of life: low satellites are lowered until drag pulls them in to burn up, while geostationary satellites are pushed about 300 km higher into a graveyard orbit.

Fastest Spacecraft Ever Built

The fastest satellites orbiting Earth top out at around 28,000 km/h in circular orbits and about 36,000 km/h at the low point of a strongly elliptical orbit. Spacecraft sent away from Earth go much faster, because they fall toward the Sun or swing past planets:

Can You See Satellites Moving?

Yes. On a clear night, low Earth orbit satellites look like steady, non-blinking points of light gliding across the sky, crossing from horizon to horizon in about 4 to 10 minutes. They are easiest to spot in the first hours after sunset and before sunrise, when you are in darkness but the satellite is still lit by the Sun.

• ISS: the brightest satellite, visible for up to about 7 minutes per pass. NASA's Spot the Station service lists passes for your location.
• Starlink trains: visible for a few nights after a launch as a line of moving dots.
• Geostationary satellites: too far away to see without a telescope, and they appear to stand still.

How Fast Do Earth Observation Satellites Travel?

Most optical, radar and hyperspectral imaging satellites fly sun-synchronous low Earth orbits between about 500 and 800 km. At those heights they travel at about 27,000 to 27,400 km/h (7.5 to 7.6 km/s) and circle Earth 14 to 15 times a day, with each orbit taking about 95 to 99 minutes. These are the speeds of satellites XRTech sources imagery from:

Gaofen-4 shows the trade-off between speed and altitude. From geostationary orbit it moves at less than half the speed of the low-orbit satellites and stays above the same region, so it can stare at one area and image it again and again through the day, which is ideal for tracking wildfires, floods and storms as they develop. Low-orbit satellites give up that constant view in exchange for far finer detail, because they are 50 to 70 times closer to the ground.

Gaofen-4 imaged this wildfire smoke plume in Gaoming District, Foshan, a dozen times over three days. From geostationary orbit the satellite never leaves the region.

Why Satellite Speed Matters for Satellite Imagery

Every high-resolution image of Earth is taken by a satellite moving over the ground at about 7 km/s. That speed shapes how imagery is collected, how often an area can be revisited and how sharp the result is. Most imaging satellites fly sun-synchronous orbits at 450 to 800 km, crossing the equator at the same local time on every pass so lighting and shadows stay consistent between images.

• Line-by-line scanning: pushbroom sensors build the image one line at a time as the satellite moves. At 7 km/s, a 30 cm strip of ground passes in about 43 millionths of a second, so sensors use time delay integration to gather enough light for a sharp picture.
• Faster revisit: agile satellites tilt to image targets hundreds of kilometres off their track, and a constellation of many satellites can revisit the same site daily or more often.
• Stereo in one pass: a satellite can photograph the same area looking forward and then backward on a single pass, giving the two angles needed for stereo satellite imagery, elevation models and 3D maps.
• All-weather coverage: SAR satellites fly the same fast low orbits but see through cloud and darkness with radar.

Because the satellite moves along its orbit, it can image the same site from two positions on one pass. The parallax between the two views is turned into a point cloud, a surface model and a 3D city model.

Free missions such as Sentinel-2 and Landsat image the whole planet every few days at 10 to 30 m resolution. Commercial satellites at similar speeds capture 30 to 50 cm detail on request. Even Google Earth's imagery comes from these fast-moving satellites, combined with aerial photography.

Sentinel-2 orbits at 786 km and about 26,850 km/h, covering every land surface on Earth every few days.

Satellite Speed FAQs

Sources

• NASA: Space Station facts and figures
• ESA: Types of orbits
• GPS.gov: GPS space segment
• USGS: Landsat 9
• NASA: Parker Solar Probe close approach
• Jonathan McDowell: Starlink statistics
• JAXA: How fast is a satellite?
• NASA: Spot the Station