Circling the globe thousands of times a year and traveling at incredible speeds, NOAA satellites use a variety of complex sensors and instruments to take highly accurate measurements of Earth and our space environment.
However, satellites don’t all follow the same paths or orbit Earth at the same distance. How and where they fly depends on what they’re designed to do.
The three types of orbits that NOAA satellites follow are:
- Low Earth (Polar-orbiting)
- Geostationary
- Deep Space
Low Earth Orbit (LEO)
Satellites in Low Earth Orbit (LEO) circle relatively close to Earth, typically between about 100 and 1,200 miles above the surface.
Because they orbit so close to Earth, LEO satellites move very quickly. Their proximity allows them to capture highly detailed images and measurements in straight paths called swaths, which are digitally combined to create a complete image of Earth from space.
NOAA’s LEO Satellites
Data from NOAA’s polar-orbiting satellites provide roughly 85 percent of the data used in numerical weather prediction models, supporting forecasts 3- to 7-days in advance.
NOAA operates the Joint Polar Satellite System (JPSS) in a type of low earth orbit known as a polar orbit. Traveling pole-to-pole at an altitude of about 512 miles, these satellites circle the globe 14 times each day. This allows each satellite to observe the whole planet twice daily, rather than focusing on a single region like geostationary satellites.
These global satellite observations serve as the backbone of both short- and long-term weather forecasts, including those that help us predict and prepare for severe weather events.
Low Earth Orbit Distance Comparisons
- NOAA’s JPSS satellites orbit approximately 500 miles above the Earth.
- Commercial airplanes fly approximately 7 miles above Earth.
- The International Space Station orbits at approximately 240 miles above Earth.
- NASA’s Hubble Space Telescope orbits at approximately 300 miles above Earth.
Geostationary Orbit (GEO)
Satellites in geostationary (GEO) orbit are much farther out from Earth than LEO satellites at just over 22,000 miles above the equator.
At that distance, they circle the planet once every 24 hours, at a speed equal to the Earth’s rotation. This allows them to remain fixed over the same region, providing continuous, near real-time monitoring of weather conditions below.
Data from geostationary satellites is used for short-term (1-to-2 day) forecasts, and to track severe weather and hazards as they happen. GEO satellites also help scientists track large-scale weather systems and monitor how conditions evolve over time, though with less detail than LEO satellites.
NOAA’s GEO Satellites
NOAA operates the Geostationary Operational Environmental Satellites (GOES)-R Series. The GOES East and GOES West satellites are fixed over the Atlantic and Pacific Oceans and watch over the Western Hemisphere. Together, they cover more than half the globe—from the west coast of Africa to New Zealand and from near the Arctic Circle to the Antarctic Circle.
The GOES-R Series provides advanced satellite imagery and atmospheric measurements, near real-time mapping of lightning activity, and monitor space weather.
Deep Space Orbit
L1 lies nearly one million miles away between the Earth and the sun, where the gravitational pull of both balances in a way that allows spacecraft to hold a relatively stable position while keeping an uninterrupted view of the sun.
To stay near this spot, NOAA’s deep-space satellites follow carefully designed paths known as Lissajous orbits. This type of complex orbit loops around the L1 point in three dimensions, oscillating above and below the plane of Earth’s orbit while also moving side-to-side across the sun–Earth line. Rather than tracing a simple, closed-loop pattern, the spacecraft follows what is known as a quasiperiodic path, which gradually shifts over time.
From Earth, this motion appears as a small looping pattern around the sun in the sky. At its closest approach, the spacecraft appears only a few degrees away from the sun, and at its farthest, a bit more than 10 degrees away. Despite this apparent offset, the spacecraft remains closely aligned with the sun–Earth line, never straying more than a fraction of a percent from it. This geometry allows the spacecraft to maintain an uninterrupted view of the sun while keeping its communications signals clear of the sun’s intense glare.
The orbital paths followed near L1 arise from the complex gravitational interactions involving the sun, Earth and the spacecraft—a scenario known as the three-body problem. Instead of remaining stationary, the spacecraft intentionally drifts slightly away from the exact center of the L1 region. The combined gravitational pull of the Earth and sun then gently pulls it back, helping sustain the looping motion. A complete cycle around the L1 region typically takes about 180 days.
Because Lissajous and other orbits around L1 are naturally unstable, sometimes spacecraft must make small course corrections using onboard thrusters. These brief maneuvers, called station-keeping burns, help keep the spacecraft on their intended path. The process is similar to making subtle steering corrections while driving down a long, straight road, with gravity doing most of the work.
NOAA’s Deep Space Satellite
Satellites such as the Space weather Observations at L1 to Advance Readiness (SOLAR-1) can detect potentially disruptive solar storms and other space weather events before their effects reach our planet. These missions help safeguard our satellites, power grids, communications systems and navigation networks that modern society depends on. They also provide advance warning of hazardous radiation conditions, helping to protect astronauts working in space.