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By NASA
The NISAR mission will help map crops and track their development through the entire growing season. Using synthetic aperture radar, the satellite will be able to observe both small plots of farmland and monitor trends across broad regions, gathering data to in-form agricultural decision making.Adobe Stock/Greg Kelton Data from the NISAR satellite will be used to map crop growth, track plant health, and monitor soil moisture — offering detailed, timely information for decision making.
When it launches this year, the NISAR (NASA-ISRO Synthetic Aperture Radar) satellite will provide a powerful data stream that could help farmers in the U.S. and around the world. This new Earth mission by NASA and the Indian Space Research Organisation will help monitor the growth of crops from planting to harvest, generating crucial insights on how to time plantings, adjust irrigation schedules, and, ultimately, make the most of another precious resource: time.
Using synthetic aperture radar, NISAR will discern the physical characteristics of crops, as well as the moisture content of the plants and the soil they grow in. The mission will have the resolution to see small plots of farmland, but a potentially more meaningful benefit will come from its broad, frequent coverage of agricultural regions.
The satellite will image nearly all of Earth’s land twice every 12 days and will be able to resolve plots down to 30 feet (10 meters) wide. The cadence and resolution could allow users to zoom in to observe week-to-week changes on small farms or zoom out to monitor thousands of farms for broader trends. Such big-picture perspective will be useful for authorities managing crops or setting farm policy.
Tapping NISAR data, decision-makers could, for example, estimate when rice seedlings were planted across a region and track their height and blooming through the season while also monitoring the wetness of the plants and paddies over time. An unhealthy crop or drier paddies may signal the need to shift management strategies.
NISAR will provide maps of croplands on a global basis every two weeks. Observations will be uninterrupted by weather and provide up-to-date information on the large-scale trends that affect international food security. Credit: NASA/JPL-Caltech “It’s all about resource planning and optimizing, and timing is very important when it comes to crops: When is the best time to plant? When is the best time to irrigate? That is the whole game here,” said Narendra Das, a NISAR science team member and agricultural engineering researcher at Michigan State University in East Lansing.
Mapping Crops
NISAR is set to launch this year from ISRO’s Satish Dhawan Space Centre on India’s southeastern coast. Once in operation, it will produce about 80 terabytes of data products per day for researchers and users across numerous areas, including agriculture.
Satellites have been used for large-scale crop monitoring for decades. Because microwaves pass through clouds, radar can be more effective at observing crops during rainy seasons than other technologies such as thermal and optical imaging. The NISAR satellite will be the first radar satellite to employ two frequencies, L- and S-band, which will enable it to observe a broader range of surface features than a single instrument working at one frequency.
Microwaves from the mission’s radars will be able to penetrate the canopies of crops such as corn, rice, and wheat, then bounce off the plant stalks, soil, or water below, and then back to the sensor. This data will enable users to estimate the mass of the plant matter (biomass) that’s aboveground in an area. By interpreting the data over time and pairing it with optical imagery, users will be able to distinguish crop types based on growth patterns.
Data gathered in 2017 by the European Sentinel-1 SAR satellite program shows changes to croplands in the region southeast of Florida’s Lake Okeechobee. Colors in the fields indicate various crops in different parts of their growth and harvest cycles. NISAR will gather similar data in L- and S-band radar frequencies.ESA; processing and visualization by Earth Big Data LLC Additionally, NISAR’s radars will measure how the polarization, or vertical and horizontal orientation of signals, changes after they bounce back to the satellite from the surface. This will enable a technique called polarimetry that, when applied to the data, will help identify crops and estimate crop production with better accuracy.
“Another superpower of NISAR is that when its measurements are integrated with traditional satellite observations, especially vegetation health indexes, it will significantly enhance crop information,” added Brad Doorn, who oversees NASA’s water resources and agriculture research program.
The NISAR satellite’s high-resolution data on which crops are present and how well they are growing could feed into agricultural productivity forecasts.
“The government of India — or any government in the world — wants to know the crop acreage and the production estimates in a very precise way,” said Bimal Kumar Bhattacharya, the agricultural applications lead at ISRO’s Space Applications Centre in Ahmedabad. “The high-repeat time-series data of NISAR will be very, very helpful.”
Tracking Soil Moisture
The NISAR satellite can also help farmers gauge the water content in soil and vegetation. In general, wetter soils tend to return more signals and show up brighter in radar imagery than drier soils. There is a similar relationship with plant moisture.
A collaboration between NASA and the Indian Space Research Organisation, NISAR will use synthetic aperture radar to offer insights into change in Earth’s ecosystems, including its agricultural lands. The spacecraft, depicted here in an artist’s concept, will launch from India.NASA/JPL-Caltech These capabilities mean that NISAR can estimate the water content of crops over a growing season to help determine if they are water-stressed, and it can use signals that have scattered back from the ground to estimate soil moisture.
The soil moisture data could potentially inform agriculture and water managers about how croplands respond to heat waves or droughts, as well as how quickly they absorb water and then dry out following rain — information that could support irrigation planning.
“Resource managers thinking about food security and where resources need to go are going to be able to use this sort of data to have a holistic view of their whole region,” said Rowena Lohman, an Earth sciences researcher at Cornell University in Ithaca, New York, and soil moisture lead on the NISAR science team.
More About NISAR
The NISAR satellite is a joint collaboration between NASA and ISRO and marks the first time the two agencies have cooperated on flight hardware for an Earth-observing mission. Managed by Caltech, NASA’s Jet Propulsion Laboratory leads the U.S. component of the project and provided the L-band SAR. NASA JPL also provided the radar reflector antenna, the deployable boom, a high-rate communication subsystem for science data, GPS receivers, a solid-state recorder, and payload data subsystem. NASA’s Goddard Space Flight Center manages the Near Space Network, which will receive NISAR’s L-band data.
The ISRO Space Applications Centre is providing the mission’s S-band SAR. The U R Rao Satellite Centre provided the spacecraft bus. The launch vehicle is from Vikram Sarabhai Space Centre, launch services are through Satish Dhawan Space Centre, and satellite mission operations are by the ISRO Telemetry Tracking and Command Network. The National Remote Sensing Centre is responsible for S-band data reception, operational products generation, and dissemination.
To learn more about NISAR, visit:
https://nisar.jpl.nasa.gov
How NISAR Will See Earth What Sets NISAR Apart From Other Earth Satellites News Media Contacts
Andrew Wang / Jane J. Lee
Jet Propulsion Laboratory, Pasadena, Calif.
626-379-6874 / 818-354-0307
andrew.wang@jpl.nasa.gov / jane.j.lee@jpl.nasa.gov
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Last Updated Mar 12, 2025 Related Terms
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Explore Hubble Hubble Home Overview About Hubble The History of Hubble Hubble Timeline Why Have a Telescope in Space? Hubble by the Numbers At the Museum FAQs Impact & Benefits Hubble’s Impact & Benefits Science Impacts Cultural Impact Technology Benefits Impact on Human Spaceflight Astro Community Impacts Science Hubble Science Science Themes Science Highlights Science Behind Discoveries Hubble’s Partners in Science Universe Uncovered Explore the Night Sky Observatory Hubble Observatory Hubble Design Mission Operations Missions to Hubble Hubble vs Webb Team Hubble Team Career Aspirations Hubble Astronauts News Hubble News Hubble News Archive Social Media Media Resources Multimedia Multimedia Images Videos Sonifications Podcasts e-Books Online Activities Lithographs Fact Sheets Posters Hubble on the NASA App Glossary More 35th Anniversary Online Activities 6 Min Read NASA’s Hubble Finds Kuiper Belt Duo May Be Trio
This artist’s concept depicts one of the possible scenarios for the 148780 Altjira system in the solar system’s Kuiper Belt. Credits:
NASA, ESA, Joseph Olmsted (STScI) The puzzle of predicting how three gravitationally bound bodies move in space has challenged mathematicians for centuries, and has most recently been popularized in the novel and television show “3 Body Problem.” There’s no problem, however, with what a team of researchers say is likely a stable trio of icy space rocks in the solar system’s Kuiper Belt, found using data from NASA’s Hubble Space Telescope and the ground-based W. M. Keck Observatory in Hawaii.
If confirmed as the second such three-body system found in the region, the 148780 Altjira system suggests there could be similar triples waiting to be discovered, which would support a particular theory of our solar system’s history and the formation of Kuiper Belt objects (KBOs).
“The universe is filled with a range of three-body systems, including the closest stars to Earth, the Alpha Centauri star system, and we’re finding that the Kuiper Belt may be no exception,” said the study’s lead author Maia Nelsen, a physics and astronomy graduate of Brigham Young University in Provo, Utah.
Known since 1992, KBOs are primitive icy remnants from the early solar system found beyond the orbit of Neptune. To date, over 3,000 KBOs have been cataloged, and scientists estimate there could be several hundred thousand more that measure over 10 miles in diameter. The largest KBO is dwarf planet Pluto.
The Hubble finding is crucial support for a KBO formation theory, in which three small rocky bodies would not be the result of collision in a busy Kuiper Belt, but instead form as a trio directly from the gravitational collapse of matter in the disk of material surrounding the newly formed Sun, around 4.5 billion years ago. It’s well known that stars form by gravitational collapse of gas, commonly as pairs or triples, but that idea that cosmic objects like those in the Kuiper Belt form in a similar way is still under investigation.
This artist’s concept depicts one of the possible scenarios for the 148780 Altjira system in the solar system’s Kuiper Belt. It is likely a hierarchical triple formation, in which two very close companions are orbited by a third member at a greater distance. The inner bodies are too close together to be resolved by the Hubble Space Telescope. But Hubble observations of the orbit of the outermost object were used to determine that the central body is not a single spherical object. Other possibilities are that the inner object is a contact binary, where two separate bodies become so close they touch each other. Another idea is that the central body is oddly flat, like a pancake. Of the 40 identified binary objects in the Kuiper Belt, another system, Lempo, has been found to be a triple. The Altjira system is located in the outer reaches of the solar system, 3.7 billion miles away, or 44 times the distance between Earth and the Sun. In this artist’s concept, our Sun is in the constellation Sagittarius, with the Milky Way in the background. The bright red star Antares appears at the top center. Dust in the plane of our solar system glows as zodiacal light. NASA, ESA, Joseph Olmsted (STScI) The Altjira system is located in the outer reaches of the solar system, 3.7 billion miles away, or 44 times the distance between Earth and the Sun. Hubble images show two KBOs located about 4,700 miles (7,600 kilometers) apart. However, researchers say that repeated observations of the objects’ unique co-orbital motion indicate the inner object is actually two bodies that are so close together they can’t be distinguished at such a great distance.
“With objects this small and far away, the separation between the two inner members of the system is a fraction of a pixel on Hubble’s camera, so you have to use non-imaging methods to discover that it’s a triple,” said Nelsen.
This takes time and patience, Nelsen explained. Scientists have gathered a 17-year observational baseline of data from Hubble and the Keck Observatory, watching the orbit of the Altjira system’s outer object.
“Over time, we saw the orientation of the outer object’s orbit change, indicating that the inner object was either very elongated or actually two separate objects,” said Darin Ragozzine, also of Brigham Young University, a co-author of the Altjira study.
“A triple system was the best fit when we put the Hubble data into different modeling scenarios,” said Nelsen. “Other possibilities are that the inner object is a contact binary, where two separate bodies become so close they touch each other, or something that actually is oddly flat, like a pancake.”
Currently, there are about 40 identified binary objects in the Kuiper Belt. Now, with two of these systems likely triples, the researchers say it is more likely they are looking not at an oddball, but instead a population of three-body systems, formed by the same circumstances. However, building up that evidence takes time and repeated observations.
Recent research using data from the Keck Observatory and NASA’s Hubble Space Telescope has revealed a potential three-body system in the Kuiper Belt, known as the Altjira system. This discovery challenges traditional collision theories by suggesting that these triple systems might form directly from the gravitational collapse of material in the early solar disk.
Nasa’s Goddard Space Flight Center; Producer: Paul Morris The only Kuiper Belt objects that have been explored in detail are Pluto and the smaller object Arrokoth, which NASA’s New Horizons mission visited in 2015 and 2019, respectively. New Horizons showed that Arrokoth is a contact binary, which for KBOs means that two objects that have moved closer and closer to one another are now touching and/or have merged, often resulting in a peanut shape. Ragozzine describes Altjira as a “cousin” of Arrokoth, a member of the same group of Kuiper Belt objects. They estimate Altjira is 10 times larger than Arrokoth, however, at 124 miles (200 kilometers) wide.
While there is no mission planned to fly by Altjira to get Arrokoth-level detail, Nelsen said there is a different upcoming opportunity for further study of the intriguing system. “Altjira has entered an eclipsing season, where the outer body passes in front of the central body. This will last for the next ten years, giving scientists a great opportunity to learn more about it,” Nelsen said. NASA’s James Webb Space Telescope is also joining in on the study of Altjira as it will check if the components look the same in its upcoming Cycle 3 observations.
The Hubble study is published in The Planetary Science Journal.
The Hubble Space Telescope has been operating for over three decades and continues to make ground-breaking discoveries that shape our fundamental understanding of the universe. Hubble is a project of international cooperation between NASA and ESA (European Space Agency). NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope and mission operations. Lockheed Martin Space, based in Denver, Colorado, also supports mission operations at Goddard. The Space Telescope Science Institute (STScI) in Baltimore, Maryland, which is operated by the Association of Universities for Research in Astronomy, conducts Hubble science operations for NASA.
Facebook logo @NASAHubble @NASAHubble Instagram logo @NASAHubble Media Contact:
Claire Andreoli (claire.andreoli@nasa.gov)
NASA’s Goddard Space Flight Center, Greenbelt, Maryland
Leah Ramsay
Space Telescope Science Institute, Baltimore, Maryland
Ray Villard
Space Telescope Science Institute, Baltimore, Maryland
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Last Updated Mar 04, 2025 Editor Andrea Gianopoulos Location NASA Goddard Space Flight Center Related Terms
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By European Space Agency
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