This leads us to the topic of satellite imagery frequency: Do they photograph Earth continuously, or on a schedule?
This article explores the nuances of image frequency, differences between public/commercial options, and major data providers.
Satellite imagery frequency is determined by several factors, including the satellite's orbit, design, and mission objectives. Civilian Earth observation satellites typically operate in low Earth orbit (LEO) at altitudes ranging from 100 to 2,000 km, most often a few hundred kilometers.
The majority travel along polar orbits, usually heliocentric, enabling them to cover the entire planet’s surface. These satellites orbit Earth with a period of approximately 90-100 minutes, moving at speeds between 6.9 and 7.8 km/s.
According to the official Landsat program website, this satellite images the entire Earth every 16 days. In collaboration with Landsat 9, this revisit time shortens to 8 days for a given area.
The Copernicus mission, with two satellites (2A and 2B), offers a revisit time of 5 days, and for some applications, even 3 days when accounting for camera tilt angles (off-nadir).
These Airbus satellites cover up to 6 million km² daily—more than the entire EU’s surface area—delivering images at a 1.5-meter resolution.
Planet’s constellation of over 430 minisatellites photographs all of Earth’s land surface daily, with a resolution of 3-5 meters.
Geostationary satellites, positioned in GEO (36,000 km above the equator), capture images every 15 minutes, though these are primarily meteorological data, with an orbital speed of 3.08 km/s.
During a single orbit lasting 1-3 hours, Earth rotates, allowing the satellite to image different surface sections in narrow strips.
After a few or several days, the satellite revisits the same area—hence the concept of temporal resolution, or revisit time.
The fact that a satellite takes a picture doesn’t guarantee it will be usable. Optical satellites like Landsat or SPOT are sensitive to cloud cover, which can render images worthless. In contrast, radar satellites (SAR), such as TerraSAR-X or ICEYE (with 38+ satellites), can “see” through clouds, but their imaging frequency depends on mission goals or specific orders.
Tiltable camera systems (off-nadir) enhance flexibility by reducing revisit times, though the angle can affect image quality.
With Satellite Imagery Report OnGeo™ Intelligence, you can preview available satellite imagery before committing to a purchase, ensuring you only pay for cloud-free scenes. This enables you to reject images with clouds, optimizing your investment.
Public satellites like Landsat and Sentinel operate on transparent schedules, however, commercial satellites offer flexibility regarding satellite imagery frequency. Companies like Maxar, Airbus, and Planet offer images captured either on client request or at the operator's discretion.
Find out:
Commercial operators often build data archives for later sale, raising the question: are images saved if no one orders them? They likely capture them regularly, but the data is curated based on demand.
Analysis of provider websites and available sources reveals that not all disclose details about imaging frequency:
Planet excels in volume and frequency, Maxar and Airbus lead in quality (VHR), while public sources like USGS provide free access.
Satellites photograph Earth at varying frequencies: from every 15 minutes (Meteosat) to every 16 days (Landsat 8).
Weather conditions and operator policies complicate availability, while commercial providers blend schedules with on-demand flexibility.
Choosing a provider depends on your needs — and with OnGeo Intelligence, you can order imagery for any location on Earth in just a few moments.