Colorful vein-like structures showing the movement of ice across Antarctica are overlaid on a satellite image of the continent.

Find out how the upcoming NISAR mission, an Earth satellite designed to capture detailed views of our planet's changing surface, will provide new insights into everything from natural disasters to climate change. Plus, connect it all to STEM learning.

The next addition to NASA’s fleet of Earth Science orbiters is launching in 2024 and will represent a monumental leap forward in how we monitor our changing planet. The NISAR mission is a collaboration between NASA and the Indian Space Research Organisation that’s designed to monitor and study tiny movements of Earth’s surface from events like natural disasters and climate change.

Read on to find out how NISAR is pushing the boundaries of Earth science from space. Plus, learn how you can bring science and engineering from the mission to your students.

How NISAR Works

NISAR is among the most advanced radar systems on an Earth science mission to date due to its supersized antenna reflector, use of synthetic aperture radar, and ability to observe Earth in two different radar frequencies simultaneously.

Hear mission experts describe how the NISAR satellite will track our changing Earth in fine detail. Credit: NASA/JPL-Caltech

Extending above the spacecraft like a giant catcher's mitt, NISAR’s antenna reflector is 39 feet (12 meters) wide – the largest ever launched as part of a NASA Earth-observing mission. This antenna creates an observational window, or swath, of the surface beneath the spacecraft that is 150 miles (242 kilometers) wide. The swath size is determined by the radar wavelength and antenna size, which is important because there is a direct relationship between antenna size and the resolution of images and data that can be captured by NISAR.

The NISAR spacecraft flies over Earth's glowing blue horizon. A long boom extending above the spacecraft holds up a cylindrical structure with the antenna reflector stretched across its center.

NISAR's antenna reflector extends above the spacecraft like a catcher's mitt and is engineered to help the mission get an unprecedented view of Earth's surface. Credit: NASA/JPL-Caltech | + Expand image

We typically want the best resolution possible, but we’re limited by the size of the antenna we can build and deploy in space. Conventionally, the resolution on a satellite is a function of the wavelength it uses and the size of the antenna. The larger the wavelength, the bigger the antenna needs to be to get quality images. At typical radar wavelengths, with a 12 meter diameter reflector, the best achievable resolution would be as coarse as 10s of kilometers, which is not very useful for observing features on Earth at the human scale.

An angle extends down from a rectangle labeled radar antenna. A series of stacked ellipses representing radar pulses is at the widest part of the angle along a path labeled radar swath.

This diagram shows how synthetic aperature radar works by sending multiple radar pulses to an area on the ground from an antenna passing overhead. Credit: NASA | + Expand image

This is why NISAR utilizes an approach called synthetic aperture radar, or SAR, to synthetically magnify the resolution achievable from the antenna. With SAR, the spacecraft sends multiple signals, or pulses, to an area as it flies overhead. Each signal gets reflected back to the spacecraft, which is meticulously designed to “catch” the reflected signals thanks to its position and velocity. Each signal in the sequence is then focused into a single high-resolution image, creating an effect as if the spacecraft is using a much larger antenna.

Radar uses radio wavelengths, which are longer than those of visible light, allowing us to see through clouds and sometimes even tree coverage to the ground below, depending on the frequency of the radio waves. We’re also able to interpret a lot of information about the surface from the way the signal returns back to the orbiter. This is because NISAR will measure the amount of scatter, or dispersion, of the signal as compared to when it was originally transmitted.

For example, a rigid, sharp angled building will bounce the signal back to the receiver differently than a leafy tree. Different radio frequencies are better used for different surfaces because they are influenced by the type of surface being analyzed. To this end, NISAR is the first mission to use two different radar frequencies simultaneously. The L-Band can be used to monitor heavier vegetation and landscapes while the S-Band is better tuned for lighter vegetation and crop growth. The two wavelengths in general extend the range of sensitivity of the measurement to smaller and larger changes.

This combination of tools and features will allow NISAR to construct global maps of changes in the position of any given pixel at a scale of just centimeters as well as subtle changes in reflectivity due to land cover changes on all land and ice surfaces twice every 12 days. The resolution combined with repetition will allow scientists to monitor the changes taking place on our planet in a matter of days more comprehensively than ever before.

Specks of brightly covered squares dot an overhead image of Jefferson Parish, Louisiana. A key indicates how the colors correspond with the vertical velocity in mm/yr.

This satellite image of New Orleans is overlaid with synthetic aperature radar data from the UAVSAR instrument to show the rate at which the land was sinking in a section of New Orleans from June 2009 to July 2012. Credit: NASA/JPL-Caltech, Esri | › Learn more

What the NISAR Mission Will Show Us

Because of the massive amount of data produced by NISAR, we’ll be able to closely monitor the impacts of environmental events including earthquakes, landslides, and ice-sheet collapses. Data from NISAR could even be used to assess the risk of natural hazards.

Scientists can use NISAR to monitor tiny movements in Earth’s surface in areas prone to volcanic eruptions or landslides. These measurements are constructed using what’s called an interferogram, which looks at how the maps generated for each pass of the spacecraft have changed over time. For example, we could see immediate changes to the topography after an earthquake with an interferogram made from images NISAR collected shortly before and soon after the event.

On the left, a satellite takes a radar image of an area of Earth's surface during its first pass. On the right, during pass two, the satellite takes a radar image of the same area of the surface, which has now been displaced by an earthquake.

Using interferometry, as shown in this diagram, NISAR can capture changes or deformation in land surfaces, such as after an earthquake. | + Expand image

By tracking and recording these events and other movements on the surface leading up to natural disasters, it may be possible to identify warning signs that can improve detection and disaster response.

Two thin rectangular satellite images labeled Nov 13, 2009 and Nov 18, 2010 are followed by an equal sign and a third image of the same area with a neon colors overlaid and a heat-map scale showing movement in cm.

The first two images in this series were captured by the UAVSAR instrument during two separate passes over California's San Andreas Fault about a year apart. The two images were then combined to create the third image, which an interferogram that shows how the surface changed between the two passes of the instrument. Credit: NASA/JPL-Caltech | + Expand image

And NISAR isn’t just limited to studying the solid Earth. As missions prior have done, it will also be able to generate maps of polar ice sheets over time and detect changes in permafrost based on the regional movement of the soil below. These measurements will give climate scientists a clear picture of how much the ice is moving and deforming due to climate change and where it is thawing as the ground warms.

Additionally, NISAR can track land usage, deforestation, sea levels, and crustal deformation, informing scientists about the impacts of environmental and climate change on Earth.

Follow Along With NISAR

NISAR is scheduled to launch in 2024 from the Satish Dhawan Space Centre in Sriharikota, India, and will enter a polar orbit 460 miles (747 kilometers) above Earth. For the first 90 days after launch, the spacecraft will undergo checks and commissioning before beginning scientific observations for a primary mission designed to last three years.

Science from the mission will be downlinked to both NASA and ISRO ground stations below with data and the tools to process it freely available for download and use to all professional and citizen scientists.

Visit NASA’s NISAR mission page for the latest updates about the mission.

Teach Earth Science With NISAR

With the launch of NISAR, we will be better able to monitor and mitigate natural disasters and understand the effects of climate change. Bring the fleet of NASA Earth Science missions to your classroom with the following lessons and activities:


Student Projects and Activities


TAGS: K-12 Education, Resources, Earth Science, Climate Change, NISAR

  • Brandon Rodriguez