Satellite imagery

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Satellite images are pictures of Earth taken from space by imaging satellites owned by governments and companies. These images are licensed to governments, map makers, and businesses for uses like navigation and planning.

A quick look at history
- The earliest space pictures came from suborbital flights in the 1940s. A US V-2 rocket in 1946 sent photos from about 105 km up, much higher than earlier balloon experiments.
- The first orbital photos of Earth appeared in 1959 with Explorer 6. Moon photos from Luna 3 followed later in 1959.
- The famous Blue Marble image was taken in 1972. That same year the United States started the Landsat program, which continues to create Earth images.
- In 1977 the KH-11 program began providing more timely, real-time looking imagery. Landsat 9 was launched in 2021, continuing a long-running data set.

Who provides satellite images
- Many countries run their own programs, and Europe runs the Sentinel satellites as part of its earth observation efforts.
- Private companies also provide commercial imagery. Examples include GeoEye, Maxar (with WorldView satellites), Pléiades, SPOT, Planet Labs (Dove and SkySat), and others. Some fleets are very high resolution, able to see details smaller than a meter, while others cover large areas more slowly.
- NASA makes many of its images free for the public through the NASA Earth Observatory.

How satellite images work and what they show
- Satellites capture different kinds of light and signals, including visible light, near-infrared, infrared, and radar. This gives a wide range of information about land, water, and atmosphere.
- Image quality depends on several kinds of “resolution”: spatial (how much ground a pixel covers), spectral (how many color bands or wavelengths), temporal (how often an area is imaged), radiometric (sensitivity to light), and geometric (how accurately the image aligns with real-world distances).
- Landsat images often come in about 30-meter resolution, but some high‑resolution private satellites see details as small as a few centimeters. Aerial photography can be even sharper but is usually more expensive per area.

What’s done with the data
- The images are processed and combined with other map data in geographic information systems (GIS). They’re used for farming, weather, water and land management, urban planning, environmental monitoring, disaster response, education, and scientific research.
- Processing may include correcting for distortions and removing clouds. Large image libraries exist, and software helps turn raw data into usable maps and analyses.

Privacy and access
- Public concern exists about who can see what from above. Many providers say their images reflect what anyone could potentially see by flying over a location.
- Because the data volume is huge, specialized software and experts are often needed to analyze and extract useful information from the images.

In short, satellite imagery helps people understand the planet, plan for the future, and respond to events, using a range of instruments, partners, and applications.