NASA Earth Science: How Satellites Watch Our Planet 24/7

NASA operates one of the largest Earth-observation fleets in the world — currently 25+ active missions watching the planet across the electromagnetic spectrum. Together they measure climate, weather, ice, oceans, biosphere, atmosphere, and more, with data freely available to anyone.

Key active missions

• Landsat 9 — continues a 50-year-long record of land surface imaging in optical and thermal bands.
• NISAR — joint NASA/ISRO synthetic aperture radar that watches surface deformation and ice motion.
• PACE — Plankton, Aerosol, Cloud, and ocean Ecosystem mission, characterizing ocean biology and air pollution.
• ICESat-2 — laser altimetry that measures ice sheet elevation changes to a few centimeters.
• GRACE-FO — twin satellites that measure variations in Earth's gravity to track water and ice mass.
• OCO-2 / OCO-3 — Orbiting Carbon Observatory, mapping atmospheric CO₂.
• TEMPO — geostationary air quality observer over North America.

How the data flows

Almost all NASA Earth science data is free and open. EarthData (earthdata.nasa.gov) is the central portal. Specialized portals — Worldview, Giovanni, AppEEARS — make data accessible to researchers, educators, and the public without requiring specialized software.

Active NASA Earth missions

25+

Total data archive

~80+ petabytes (and growing)

Data access cost

Free for science and public use

Largest single mission cost

~$1B for flagships like NISAR

Update frequency for global coverage

Daily for many products

Why it matters

Climate science depends on continuous, calibrated, multi-decade satellite records. Disaster response — from wildfires to hurricanes — uses Earth observation in near-real time. Agriculture, fisheries, and water management worldwide rely on free NASA data. The fleet is some of the most cost-effective public infrastructure ever built.