NASA Earth Science Explained: Satellites, Climate and Planet Monitoring

NASA Earth science may be less famous than Moon landings, Mars rovers or the James Webb Space Telescope, but it is one of NASA’s largest and most practically important scientific activities.

NASA does not only look outward into space.

It also looks back at Earth.

More than 20 satellites operated by NASA’s Earth Science Division help researchers study our planet, while additional observations come from instruments on the International Space Station, aircraft, balloons, ships, field campaigns and sensors on the ground.

Together, these observations help scientists investigate:

• Earth’s atmosphere;
• oceans;
• freshwater;
• ice sheets and glaciers;
• forests and vegetation;
• agriculture;
• wildfires;
• air pollution;
• sea level;
• weather systems;
• carbon;
• earthquakes;
• volcanoes;
• land movement;
• climate variability and long-term change.

The key idea behind NASA Earth science is that none of these systems operates alone.

The ocean affects the atmosphere.

The atmosphere affects rainfall.

Rainfall affects rivers and agriculture.

Vegetation exchanges carbon with the atmosphere.

Ice changes sea level and reflects solar energy.

Changes in land use can influence ecosystems, water and climate.

NASA therefore studies Earth as a system, examining interactions among the water cycle, carbon cycle, atmosphere, ocean circulation, land, ice and the movement of energy through the planet.

That system-level approach is what makes NASA Earth science much more than a collection of satellite photographs.

NASA Earth Science at a Glance

Area	What NASA Studies
Atmosphere	Air quality, aerosols, ozone, clouds and atmospheric composition
Oceans	Sea level, ocean circulation, temperature and marine ecosystems
Freshwater	Rivers, lakes, reservoirs, groundwater and the water cycle
Land	Vegetation, agriculture, urban growth and land-use change
Ice	Glaciers, ice sheets, snow and sea ice
Climate	Long-term interactions among atmosphere, ocean, land and ice
Carbon cycle	Movement of carbon through atmosphere, ecosystems and oceans
Weather research	Storms, precipitation and atmospheric processes
Solid Earth	Earthquakes, volcanoes, landslides and crustal deformation
Natural hazards	Fires, floods, drought, storms and other disasters
Data	Open Earth-observation datasets for research and applications

NASA currently organizes its Earth science priorities around areas including atmospheric composition, water and energy, weather, climate variability and change, carbon and ecosystems, and Earth’s surface and interior.

What Is NASA Earth Science?

NASA Earth science is NASA’s scientific program for understanding Earth using observations from space, the air, oceans and land.

It applies many of the same techniques NASA uses to study other planets.

Scientists measure reflected light.

Infrared radiation.

Radar signals.

Atmospheric chemistry.

Gravity.

Surface height.

Temperature.

Moisture.

Vegetation.

Clouds.

Ocean color.

These measurements are then combined with field observations and computer models.

NASA’s Earth Science Division says it develops ways to observe oceans, land cover, ice, atmosphere and life, while investigating how changes in one part of the Earth system drive changes elsewhere.

That last point is essential.

NASA is not simply producing isolated maps.

It is trying to understand how an interconnected planet works.

Why Does NASA Study Earth?

NASA’s experience exploring space gives it an unusual perspective on Earth.

A satellite can repeatedly observe enormous areas using the same calibrated instruments.

That consistency makes long-term change easier to measure.

A ground observer can study one forest.

A satellite can repeatedly examine forests across continents.

A ship can measure one part of the ocean.

A satellite can observe ocean conditions over much of the planet.

A weather station can provide excellent local measurements.

A satellite can reveal the larger regional or global system around those observations.

NASA says Earth observations are used to support work involving agriculture, water and food security, urban planning, disaster preparedness, transportation, climate, weather and other societal needs.

This makes NASA Earth science both scientific and practical.

NASA Studies Earth as One System

Earth can be divided into broad components.

Atmosphere

The gases surrounding Earth.

Hydrosphere

Oceans, rivers, lakes, groundwater and other water.

Cryosphere

Ice sheets, glaciers, snow, permafrost and sea ice.

Biosphere

Living organisms and ecosystems.

Land and solid Earth

Continents, soils, rocks and the planet’s dynamic crust.

These systems constantly interact.

Consider a drought.

It may involve atmospheric circulation.

Reduced rainfall.

Higher temperatures.

Soil moisture.

Plant stress.

Water supplies.

Wildfire risk.

Agriculture.

One event touches several Earth systems.

That is why NASA Earth science increasingly focuses on relationships rather than treating every variable independently.

NASA Earth Science Satellites

NASA’s Earth-observation fleet contains many missions, each designed to measure different parts of the planet.

Important current examples include:

Mission	Main Purpose	Status in 2026
Landsat 8	Land imaging	Active
Landsat 9	Land imaging	Active
Terra	Atmosphere, land, oceans and energy	Active
SWOT	Oceans and surface water	Active
PACE	Ocean biology, aerosols and clouds	Active
TEMPO	North American air quality	Active
NISAR	Land, ice, ecosystems and surface movement	Active
Sentinel-6 Michael Freilich	Sea level	Active
Sentinel-6B	Sea level and atmospheric measurements	Active

NASA’s current Earth Science mission directory contains a much larger portfolio, so this table should be understood as a selection rather than the complete fleet.

Landsat: More Than 50 Years of Watching Earth’s Land

One of the most important programs in NASA Earth science is Landsat.

The first Landsat satellite launched in 1972.

The program, operated jointly by NASA and the U.S. Geological Survey, created the longest continuous space-based record of Earth’s land surface.

Today, Landsat 8 and Landsat 9 continue that record.

Landsat 9 launched on September 27, 2021 and operates as an active Earth-observation mission.

Landsat imagery helps researchers and resource managers monitor:

• deforestation;
• agricultural fields;
• urban growth;
• drought;
• wildfire damage;
• coastlines;
• glaciers;
• water quality;
• land-use change.

The power of Landsat does not come only from image quality.

It comes from continuity.

Researchers can compare modern observations with imagery collected decades earlier.

That makes gradual environmental change visible.

Why Long-Term Earth Records Matter

Imagine photographing a glacier once.

That photograph tells you what the glacier looked like that day.

Now photograph it repeatedly for 50 years.

The sequence tells a completely different story.

Scientists can estimate:

how quickly it changed,

whether change accelerated,

how seasonal variation compares with long-term trends.

The same principle applies to:

forests,

cities,

farmland,

coastlines,

lakes

and many other features.

This is why continuity is one of the most valuable characteristics of NASA Earth science.

Landsat Next and the Future of Land Monitoring

The Landsat record is intended to continue.

NASA and USGS are developing the next generation of the program.

Current NASA planning points toward a 2030 Landsat successor mission, with the future system intended to provide more frequent observations and expanded spectral capabilities. NASA’s current Earth Science project listings refer to the planned next mission as Landsat 10, while earlier development materials described the architecture as Landsat Next.

The terminology and architecture should therefore be checked again before publication close to launch.

The important point is that NASA intends the land-imaging record to continue.

PACE: Watching the Ocean’s Microscopic Life

NASA launched PACE on February 8, 2024.

PACE stands for:

Plankton, Aerosol, Cloud, ocean Ecosystem.

It is an active NASA Earth science mission studying interactions between oceans and atmosphere.

One major focus is phytoplankton.

These microscopic organisms live in oceans and other water bodies.

They play an enormous role in marine ecosystems and the carbon cycle.

PACE measures subtle differences in ocean color that help scientists distinguish different types and concentrations of phytoplankton.

It also studies aerosols and clouds.

That matters because tiny atmospheric particles can affect:

air quality,

cloud formation,

sunlight reaching Earth,

and climate.

PACE therefore links ocean biology with atmospheric science.

Why Ocean Color Matters

The ocean does not literally have one uniform blue color.

Different materials absorb and reflect different wavelengths.

Phytoplankton contain pigments.

Sediment changes reflected light.

Dissolved substances alter ocean color.

Sensitive satellite instruments can detect differences invisible to ordinary human vision.

PACE uses those measurements to help scientists understand marine ecosystems and ocean health.

NASA says the mission also improves understanding of the ocean carbon cycle and how climate change affects phytoplankton communities.

This demonstrates how NASA Earth science can extract biological information from light measured hundreds of kilometers above the planet.

SWOT: Measuring Earth’s Water

Another major mission is SWOT.

Its full name is:

Surface Water and Ocean Topography.

NASA and the French space agency CNES developed the mission with contributions from Canada and the United Kingdom.

SWOT launched on December 16, 2022 and remains active.

Its purpose is ambitious:

measure how water is distributed and changing across Earth’s surface.

SWOT observes:

• oceans;
• rivers;
• lakes;
• reservoirs;
• wetlands.

NASA describes it as the first global survey of Earth’s surface water at this level of detail.

Why SWOT Is Important

Water availability is one of humanity’s most practical environmental challenges.

Managers need to know:

How much water is in reservoirs?

How are lakes changing?

How much water moves through rivers?

How does the ocean surface vary?

How does sea level behave near coastlines?

SWOT combines oceanography and hydrology.

It measures water height and surface area, allowing scientists to estimate changing water volumes and study ocean circulation.

This type of observation shows how NASA Earth science can connect fundamental research with water-resource planning.

NISAR: Radar That Sees Earth Differently

One of the newest major NASA Earth science missions is NISAR.

The name stands for:

NASA-ISRO Synthetic Aperture Radar.

It is a partnership between NASA and the Indian Space Research Organisation.

NISAR launched from India on July 30, 2025 and entered routine science operations in early January 2026. NASA lists it as an active mission.

Its radar instruments can measure tiny changes in Earth’s surface.

NISAR studies:

• earthquakes;
• volcanoes;
• landslides;
• glaciers;
• ice sheets;
• agriculture;
• forests;
• wetlands;
• groundwater-related movement;
• ecosystems.

Why Radar Is So Powerful

Optical satellites rely on reflected sunlight.

Clouds can block their view.

Radar works differently.

NISAR transmits microwave signals toward Earth and measures how they return.

This allows observations through clouds and during day or night.

The mission carries both L-band and S-band synthetic-aperture radar systems.

NASA says NISAR observes Earth’s land and ice-covered surfaces globally with a 12-day repeat cycle from ascending and descending passes, producing an average revisit of roughly six days.

This makes it especially valuable for detecting change.

NISAR Data Became Available in 2026

NISAR’s importance grew further in 2026 as the mission began releasing science products.

NASA reported that provisional calibrated L-band data were released publicly in July 2026, while the spacecraft remained in its science phase.

This reinforces another central principle of NASA Earth science:

the mission is not finished when a satellite collects an image.

The real scientific value comes when observations become calibrated datasets researchers can analyze.

TEMPO: Watching Air Pollution Hour by Hour

The TEMPO instrument studies air quality over North America.

TEMPO stands for:

Tropospheric Emissions: Monitoring of Pollution.

It launched in 2023 and remains active.

From geostationary orbit, TEMPO can repeatedly measure atmospheric pollution during the day across an area extending from Mexico City to Canada’s oil sands and from the Atlantic to the Pacific.

TEMPO measures substances and atmospheric properties associated with:

ozone,

aerosols,

clouds

and air pollution.

Its ability to observe the same region frequently is especially useful.

A polar-orbiting satellite might pass over once or twice.

TEMPO can reveal how pollution changes through the day.

NASA Earth Science and Air Quality

Air pollution is not constant.

Morning traffic.

Industrial activity.

Wildfire smoke.

Weather.

Sunlight-driven chemistry.

All can change pollution concentrations over hours.

This makes high-frequency measurements valuable.

TEMPO illustrates how NASA Earth science can help bridge space-based research and local environmental questions.

NASA’s job is not to replace ground-based air-quality monitoring.

Instead, satellite observations add regional context that ground networks alone cannot provide.

Sentinel-6B and Sea-Level Monitoring

A particularly important recent mission is Sentinel-6B.

The satellite launched on November 16, 2025 and is now an active mission.

It joins Sentinel-6 Michael Freilich in measuring ocean height.

The Sentinel-6 program continues a high-precision sea-level record that began in 1992 with TOPEX/Poseidon and continued through the Jason satellite series.

Sentinel-6B measures sea level over around 90% of the world’s oceans.

It also collects atmospheric temperature and humidity information useful for weather and climate research.

Long records like this help scientists distinguish natural variability from longer-term trends.

Terra: A Veteran Still Studying Earth

Not every important NASA Earth science spacecraft is new.

NASA’s Terra satellite launched in December 1999 and remains listed as an active mission in 2026.

Terra studies interactions among:

atmosphere,

land,

ocean

and Earth’s radiant energy.

Its long lifetime demonstrates the scientific value of maintaining consistent observations.

Terra has contributed data related to:

wildfires,

vegetation,

clouds,

aerosols,

volcanoes,

surface temperatures

and many other Earth-system processes.

NASA Earth Science and Climate Change

Climate is one of the most important subjects studied by NASA.

But NASA Earth science does not measure climate using one satellite or one temperature record.

Researchers examine multiple connected variables.

These include:

• atmospheric temperature;
• ocean heat;
• sea level;
• greenhouse gases;
• glaciers;
• ice sheets;
• sea ice;
• clouds;
• aerosols;
• vegetation;
• carbon;
• rainfall;
• water storage.

Climate is a long-term Earth-system problem.

Understanding it requires observations across decades and across many parts of the planet.

NASA’s current Earth Science program explicitly lists climate variability and change as one of its major scientific focus areas.

Weather and Climate Are Not the Same Thing

Weather describes shorter-term atmospheric conditions.

Climate describes patterns and statistical behavior across longer periods.

NASA contributes research and observations relevant to both.

Earth-observing satellites provide measurements that can improve understanding of storms, atmospheric temperature, moisture and other variables used in forecasting.

However, NASA is primarily a research and science agency.

Operational U.S. weather forecasting is led by organizations such as NOAA and the National Weather Service.

NASA often develops technologies and missions whose measurements later become valuable to operational agencies.

That distinction makes descriptions of NASA Earth science more accurate.

NASA Earth Science and Wildfires

Satellites are particularly useful during large fires.

They can identify thermal hotspots.

Map smoke.

Measure burned areas.

Track vegetation before and after a fire.

Observe regional atmospheric conditions.

NASA’s Earthdata infrastructure includes FIRMS, the Fire Information for Resource Management System, which provides satellite-derived fire and hotspot information.

Satellite data cannot replace firefighters on the ground.

It can provide wider situational awareness.

Floods, Drought and Water Security

Water appears repeatedly across NASA’s Earth-observation portfolio because it connects so many environmental systems.

SWOT studies surface water.

GRACE-style gravity missions can reveal changes in water storage.

Landsat observes reservoirs and agricultural landscapes.

Weather satellites contribute rainfall observations.

NISAR can detect some land deformation associated with groundwater change.

Combining these datasets can help scientists understand drought, floods and water availability more completely than any single instrument could.

This is a recurring theme in NASA Earth science:

multiple missions answering different pieces of one problem.

Earthquakes, Volcanoes and Landslides

NASA cannot prevent an earthquake.

Nor can a satellite stop a volcanic eruption.

But Earth observations can help scientists measure how Earth’s surface changes around these events.

NISAR is particularly important because synthetic-aperture radar can detect subtle deformation of the crust.

NASA says the mission is designed to improve understanding of processes including earthquakes, volcanoes and landslides.

Repeated radar observations can show how land moved before or after an event.

This information contributes to geophysical research and hazard analysis.

NASA Earth Science and Agriculture

Satellites can observe crops and agricultural land at regional and global scales.

Measurements can reveal:

vegetation health,

soil moisture,

water stress,

changes in planted area,

drought conditions.

Landsat’s long record is particularly useful because agricultural regions can be compared across seasons and decades.

PACE and other missions add information about atmospheric and ecosystem processes.

NISAR can observe crop and vegetation structure using radar.

NASA’s Earth-observation program therefore contributes data useful to food-security research and agricultural management.

NASA Earth Science and the Carbon Cycle

Carbon moves continuously between:

atmosphere,

plants,

soils,

oceans

and rocks.

This movement is known as the carbon cycle.

Changes in one reservoir affect others.

NASA studies this system using satellites, aircraft, field observations and computer models.

Understanding carbon is important because carbon dioxide is a greenhouse gas and because carbon is fundamental to ecosystems and life.

NASA’s Earth Science program lists carbon cycle and ecosystems as one of its major scientific priorities.

PACE contributes through measurements of phytoplankton.

Land missions observe vegetation.

Atmospheric instruments measure greenhouse gases and related processes.

The result is a system-level picture.

Why NASA Earth Science Data Are Open

A major advantage of NASA Earth science is that much of the scientific data are freely available.

NASA’s Earth Science Data Systems program provides open access to the agency’s archive of Earth-observation data.

Researchers do not generally need to purchase individual satellite scenes from NASA.

The Earthdata system provides access to observations from:

satellites,

the ISS,

aircraft campaigns,

field campaigns,

in-situ instruments

and model outputs.

NASA’s Earthdata Search currently provides access to billions of Earth observations across disciplines such as atmosphere, ocean, land, cryosphere and hydrology.

Open data allows universities, governments, businesses and independent researchers around the world to build on publicly funded science.

Why One Earth Satellite Is Not Enough

Different missions answer different questions.

Landsat is excellent for detailed land imagery.

NISAR measures physical surface change with radar.

PACE studies ocean color and aerosols.

TEMPO watches atmospheric pollution frequently.

SWOT measures water height.

Sentinel-6 measures sea level with extreme precision.

No one satellite can replace the others.

The best understanding often comes when researchers combine several datasets.

For example, coastal flooding research might combine:

sea-level measurements,

rainfall,

land elevation,

soil moisture,

river levels,

storm information.

That multi-mission approach is central to NASA Earth science.

NASA Earth Science vs NASA Space Telescopes

The distinction is mostly about target and purpose.

NASA space telescopes such as Hubble and Webb look outward at the universe.

Earth-observing satellites point primarily back toward our own planet.

The engineering can still overlap.

Both require:

precision instruments,

spacecraft power,

communications,

data processing,

calibration,

orbital operations.

For the astronomy side of NASA’s science portfolio, read NASA Space Telescopes Explained.

International Partnerships

NASA rarely conducts modern Earth science completely alone.

Examples include:

NISAR with ISRO.

SWOT with France’s CNES and contributions from Canada and the United Kingdom.

Sentinel-6B with ESA, EUMETSAT, NOAA and additional European partners.

The reason is practical.

Earth is one planet.

Environmental systems cross borders.

International missions allow agencies to combine technology, funding, expertise and data.

Future of NASA Earth Science

The future of NASA Earth science will involve both continuity and new technology.

Continuity matters because long records are irreplaceable.

Scientists cannot go back to 1992 and remeasure sea level with a modern satellite.

They need overlapping missions that preserve calibration across generations.

At the same time, new instruments can provide:

higher spatial resolution,

more frequent observations,

new wavelength coverage,

better radar,

smaller satellites,

greater computing capability.

NASA’s current Earth Science Projects portfolio includes future missions planned around atmospheric composition, precipitation and continued Landsat observations around 2030.

The precise mission names and schedules can change, so future dates should always be rechecked.

NASA Earth Science Timeline

Year	Milestone
1972	First Landsat launches
1992	Modern precision satellite sea-level record begins with TOPEX/Poseidon
1999	Terra launches
2013	Landsat 8 launches
2021	Landsat 9 launches
Dec. 2022	SWOT launches
April 2023	TEMPO launches
Feb. 2024	PACE launches
July 2025	NISAR launches
Nov. 2025	Sentinel-6B launches
Jan. 2026	NISAR begins routine science operations
July 2026	NISAR provisional calibrated L-band data released
Around 2030	Next-generation Landsat and other Earth missions planned

Frequently Asked Questions About NASA Earth Science

What is NASA Earth science?

NASA Earth science is NASA’s program for studying Earth’s atmosphere, oceans, water, land, ecosystems, ice, climate and solid Earth using satellites, aircraft, field observations and computer models.

Why does NASA study Earth?

Earth is a planet, and NASA applies its scientific and spaceflight expertise to understanding how our planet’s interconnected systems work and change.

How many Earth satellites does NASA operate?

NASA’s Earth Science Division currently says it operates more than 20 satellites in orbit, alongside additional research campaigns and instruments.

What is Landsat?

Landsat is the NASA-USGS program that has produced the longest continuous space-based record of Earth’s land surface since 1972. Landsat 8 and Landsat 9 are active.

What is PACE?

PACE is an active NASA mission launched in February 2024 that studies phytoplankton, ocean color, aerosols and clouds to improve understanding of oceans, atmosphere and climate.

What does SWOT measure?

SWOT measures the height and changing distribution of Earth’s oceans and surface freshwater, including rivers, lakes and reservoirs.

What is NISAR?

NISAR is a NASA-ISRO radar mission launched in July 2025. It observes changes in Earth’s land, ice, water and vegetation and entered its science phase in 2026.

Does NASA monitor air pollution?

Yes. TEMPO is one active NASA instrument that measures air pollution across North America at high temporal resolution.

Does NASA study climate change?

Yes. Climate variability and change is one of NASA Earth Science’s major research areas, alongside atmospheric composition, water, weather, ecosystems and Earth’s surface.

Does NASA predict the weather?

NASA conducts atmospheric research and provides observations useful for weather forecasting, but operational U.S. forecasts are primarily produced by NOAA and the National Weather Service.

Is NASA Earth science data free?

NASA’s Earth Science Data Systems program provides open access to NASA Earth-observation data through Earthdata and related services.

How does NASA Earth science help with disasters?

Satellite data can help researchers and responders observe fires, floods, storms, landslides, volcanic activity and other hazards while improving understanding of how those events develop and affect communities.

Conclusion: NASA Earth Science Turns Space Into a Tool for Understanding Home

The most important destination for some NASA spacecraft is not Mars.

Not the Moon.

Not Jupiter.

Not another star.

It is Earth.

NASA Earth science turns the perspective of space exploration back toward the planet where every human lives.

Landsat shows how forests, cities, agriculture and landscapes change over decades.

SWOT measures Earth’s surface water.

PACE examines microscopic life in the ocean and tiny particles in the atmosphere.

TEMPO watches pollution change across North America.

Sentinel-6B extends a sea-level record that reaches back to 1992.

NISAR uses radar to measure how land, ice and ecosystems change with extraordinary precision.

Individually, each mission studies part of the planet.

Together, they reveal Earth as a system.

That system is complicated.

Oceans absorb heat and carbon.

Clouds influence Earth’s energy balance.

Ice stores enormous amounts of freshwater.

Vegetation moves carbon between land and atmosphere.

Rain connects atmosphere and land.

Rivers transport water and sediment.

Human cities and agriculture change the surface.

Wildfires alter ecosystems and air quality.

No one measurement can explain all of it.

That is why NASA Earth science depends on a fleet rather than one perfect satellite.

It also depends on time.

Landsat observations stretch back more than half a century.

Satellite sea-level measurements now span more than three decades.

Long records help researchers distinguish a temporary event from a persistent trend.

They allow today’s measurements to be compared with the past.

And they give future scientists something that cannot be recreated later:

a record of what Earth looked like now.

The scientific value goes beyond academic research.

NASA Earth observations are used in work related to agriculture, water, wildfires, natural hazards, air quality, infrastructure and disaster response.

Perhaps equally important is the way NASA distributes the information.

Earth science observations are broadly available through NASA’s open-data infrastructure.

Researchers around the world can access enormous archives without needing to own a satellite.

That allows one mission to support thousands of separate investigations.

A satellite may have one set of instruments.

Its data can answer questions the original mission team never anticipated.

That is one reason NASA Earth science should be treated as a major part of the NASA pillar rather than a small climate subsection.

NASA explores other worlds to understand the universe.

It studies Mars to learn whether another planet was once habitable.

It studies distant planets to understand how planetary systems form.

But Earth remains the only world known to support life.

Understanding how it works is therefore not secondary to planetary science.

It is one of planetary science’s most important challenges.

For the complete agency overview, read NASA Explained.

For the historical development of NASA’s scientific programs, read NASA History Explained.

For NASA’s current human return to lunar exploration, see NASA Artemis Program Explained.

For robotic planetary exploration beyond Earth, read NASA Mars Missions Explained.

For NASA observatories looking outward into the universe, continue with NASA Space Telescopes Explained.

For NASA’s efforts to understand and respond to hazardous near-Earth objects, read NASA Planetary Defense Explained.

Authoritative Sources Used

NASA Earth Science Division overview and current program structure.

NASA Earth Science mission directory.

NASA/USGS Landsat mission information.

NASA PACE and SWOT mission information.

NASA-ISRO NISAR mission information.

NASA Sentinel-6B mission information.

NASA Earthdata open-data resources.

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