Jump to content

How New NASA, India Earth Satellite NISAR Will See Earth


Recommended Posts

  • Publishers
Posted

Set to launch within a few months, NISAR will use a technique called synthetic aperture radar to produce incredibly detailed maps of surface change on our planet.

When NASA and the Indian Space Research Organization’s (ISRO) new Earth satellite NISAR (NASA-ISRO Synthetic Aperture Radar) launches in coming months, it will capture images of Earth’s surface so detailed they will show how much small plots of land and ice are moving, down to fractions of an inch. Imaging nearly all of Earth’s solid surfaces twice every 12 days, it will see the flex of Earth’s crust before and after natural disasters such as earthquakes; it will monitor the motion of glaciers and ice sheets; and it will track ecosystem changes, including forest growth and deforestation.  

The mission’s extraordinary capabilities come from the technique noted in its name: synthetic aperture radar, or SAR. Pioneered by NASA for use in space, SAR combines multiple measurements, taken as a radar flies overhead, to sharpen the scene below. It works like conventional radar, which uses microwaves to detect distant surfaces and objects, but steps up the data processing to reveal properties and characteristics at high resolution.

To get such detail without SAR, radar satellites would need antennas too enormous to launch, much less operate. At 39 feet (12 meters) wide when deployed, NISAR’s radar antenna reflector is as wide as a city bus is long. Yet it would have to be 12 miles (19 kilometers) in diameter for the mission’s L-band instrument, using traditional radar techniques, to image pixels of Earth down to 30 feet (10 meters) across.

Synthetic aperture radar “allows us to refine things very accurately,” said Charles Elachi, who led NASA spaceborne SAR missions before serving as director of NASA’s Jet Propulsion Laboratory in Southern California from 2001 to 2016. “The NISAR mission will open a whole new realm to learn about our planet as a dynamic system.”

A satellite with large solar panels orbiting the Earth, with a large antenna array visible.
Data from NASA’s Magellan spacecraft, which launched in 1989, was used to create this image of Crater Isabella, a 108-mile-wide (175-kilometer-wide) impact crater on Venus’ surface. NISAR will use the same basic SAR principles to measure properties and characteristics of Earth’s solid surfaces.
NASA/JPL-Caltech

How SAR Works

Elachi arrived at JPL in 1971 after graduating from Caltech, joining a group of engineers developing a radar to study Venus’ surface. Then, as now, radar’s allure was simple: It could collect measurements day and night and see through clouds. The team’s work led to the Magellan mission to Venus in 1989 and several NASA space shuttle radar missions.

An orbiting radar operates on the same principles as one tracking planes at an airport. The spaceborne antenna emits microwave pulses toward Earth. When the pulses hit something — a volcanic cone, for example — they scatter. The antenna receives those signals that echo back to the instrument, which measures their strength, change in frequency, how long they took to return, and if they bounced off of multiple surfaces, such as buildings.

This information can help detect the presence of an object or surface, its distance away, and its speed, but the resolution is too low to generate a clear picture. First conceived at Goodyear Aircraft Corp. in 1952, SAR addresses that issue.

“It’s a technique to create high-resolution images from a low-resolution system,” said Paul Rosen, NISAR’s project scientist at JPL.

As the radar travels, its antenna continuously transmits microwaves and receives echoes from the surface. Because the instrument is moving relative to Earth, there are slight changes in frequency in the return signals. Called the Doppler shift, it’s the same effect that causes a siren’s pitch to rise as a fire engine approaches then fall as it departs.

Computer processing of those signals is like a camera lens redirecting and focusing light to produce a sharp photograph. With SAR, the spacecraft’s path forms the “lens,” and the processing adjusts for the Doppler shifts, allowing the echoes to be aggregated into a single, focused image.

Using SAR

One type of SAR-based visualization is an interferogram, a composite of two images taken at separate times that reveals the differences by measuring the change in the delay of echoes. Though they may look like modern art to the untrained eye, the multicolor concentric bands of interferograms show how far land surfaces have moved: The closer the bands, the greater the motion. Seismologists use these visualizations to measure land deformation from earthquakes.

Another type of SAR analysis, called polarimetry, measures the vertical or horizontal orientation of return waves relative to that of transmitted signals. Waves bouncing off linear structures like buildings tend to return in the same orientation, while those bouncing off irregular features, like tree canopies, return in another orientation. By mapping the differences and the strength of the return signals, researchers can identify an area’s land cover, which is useful for studying deforestation and flooding.

Such analyses are examples of ways NISAR will help researchers better understand processes that affect billions of lives.

“This mission packs in a wide range of science toward a common goal of studying our changing planet and the impacts of natural hazards,” said Deepak Putrevu, co-lead of the ISRO science team at the Space Applications Centre in Ahmedabad, India.

Learn more about NISAR at:

https://nisar.jpl.nasa.gov

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

2025-006

Keep Exploring

Discover More Topics From NASA

View the full article

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Similar Topics

    • By NASA
      NASA astronauts work to retrieve batteries and adapter plates from an external pallet during a spacewalk to upgrade the International Space Station’s power storage capacity.Credit: NASA Two NASA astronauts will venture outside the International Space Station, conducting U.S. spacewalk 93 on Thursday, May 1, to complete station upgrades.
      NASA will preview the upcoming spacewalk during a news conference at 2 p.m. EDT on Thursday, April 24, on the agency’s website from NASA’s Johnson Space Center in Houston. Learn how to watch NASA content through a variety of platforms, including social media.
      Participants in the news conference include:
      Bill Spetch, operations integration manager, International Space Station Program Diana Trujillo, spacewalk flight director, NASA Johnson Media interested in participating in person or by phone must contact the Johnson newsroom no later than 10 a.m. on Wednesday, April 23, at: 281-483-5111 or jsccommu@mail.nasa.gov. To ask questions, media must dial in no later than 15 minutes prior to the start of the news conference. Questions also may be submitted on social media using #AskNASA.
      The spacewalk is scheduled to last about six and a half hours. NASA will provide additional information, including live NASA+ coverage details, when available.
      NASA astronauts Anne McClain and Nichole Ayers will relocate a space station communications antennae and install a mounting bracket ahead of the installation of an additional set of International Space Station Rollout Solar Arrays, also called IROSA. The arrays will boost power generation capability by up to 30%, increasing the station’s total available power from 160 kilowatts to up to 215 kilowatts. The arrays will be installed on a future spacewalk following their arrival on a SpaceX Dragon commercial resupply services mission later this year.
      McClain will serve as spacewalk crew member 1 and will wear a suit with red stripes. Ayers will serve as spacewalk crew member 2 and will wear an unmarked suit. This will be the third spacewalk for McClain and the first for Ayers. U.S. spacewalk 93 will be the 275th spacewalk in support of space station assembly, maintenance, and upgrades.
      Learn more about International Space Station research and operations at:
      https://www.nasa.gov/station
      -end-
      Josh Finch / Claire O’Shea
      Headquarters, Washington
      202-358-1100
      joshua.a.finch@nasa.gov / claire.a.oshea@nasa.gov
      Sandra Jones
      Johnson Space Center, Houston
      281-483-5111
      sandra.p.jones@nasa.gov
      Share
      Details
      Last Updated Apr 18, 2025 LocationNASA Headquarters Related Terms
      International Space Station (ISS) Humans in Space ISS Research Johnson Space Center View the full article
    • By NASA
      2 min read
      Preparations for Next Moonwalk Simulations Underway (and Underwater)
      NASA’s C-130, now under new ownership, sits ready for its final departure from NASA’s Wallops Flight Facility in Virginia, on Friday, April 18, 2025. NASA/Garon Clark NASA’s C-130 Hercules, fondly known as the Herc, went wheels up at 9:45 a.m., Friday, April 18, as it departed from its decade-long home at NASA’s Wallops Flight Facility in Virginia, for the final time. The aircraft is embarking on a new adventure to serve and protect in the state of California where it is now under the ownership of the California Department of Forestry and Fire Protection (CAL FIRE). 
      The transition of the C-130 to CAL FIRE is part of a long-running, NASA-wide aircraft enterprise-management activity to consolidate the aircraft fleet and achieve greater operational efficiencies while reducing the agency’s infrastructure footprint. 
      The C-130 Hercules takes off for the final time from NASA’s Wallops Flight Facility in Virginia.NASA/Garon Clark “Our C-130 and the team behind it has served with great distinction over the past decade,” said David L. Pierce, Wallops Flight Facility director. “While our time with this amazing airframe has come to a close, I’m happy to see it continue serving the nation in this new capacity with CAL FIRE.”  
      The research and cargo aircraft, built in 1986, was acquired by NASA in 2015. Over the past decade, the C-130 supported the agency’s airborne scientific research, provided logistics support and movement of agency cargo, and supported technology demonstration missions. The aircraft logged approximately 1,820 flight hours in support of missions across the world during its time with the agency. 
      Additional aircraft housed at NASA Wallops will be relocated to NASA’s Langley Research Center in Hampton, Virginia, in the coming months. 
      For more information on NASA’s Wallops Flight Facility, visit: www.nasa.gov/wallops. 
      By Olivia Littleton
      NASA’s Wallops Flight Facility, Wallops Island, Va.
      Share
      Details
      Last Updated Apr 18, 2025 EditorOlivia F. LittletonLocationWallops Flight Facility Related Terms
      Wallops Flight Facility Explore More
      4 min read NASA to Launch Three Rockets from Alaska in Single Aurora Experiment
      UPDATE March 31, 2025: The third and final rocket of the AWESOME mission launched on Saturday,…
      Article 4 weeks ago 5 min read NASA Super Pressure Balloons Return to New Zealand for Test Flights
      Article 1 month ago 2 min read NASA Wallops Breaks Ground on New Causeway Bridge
      Article 4 days ago View the full article
    • By NASA
      3 min read
      Preparations for Next Moonwalk Simulations Underway (and Underwater)
      NASA test pilot Nils Larson inspects the agency’s F-15D research aircraft at NASA’s Armstrong Flight Research Center in Edwards, California, ahead of a calibration flight for a newly installed near-field shock-sensing probe. Mounted on the F-15D, the probe is designed to measure shock waves generated by the X-59 quiet supersonic aircraft during flight. The data will help researchers better understand how shock waves behave in close proximity to the aircraft, supporting NASA’s Quesst mission to enable quiet supersonic flight over land.NASA/Steve Freeman NASA test pilot Nils Larson inspects the agency’s F-15D research aircraft at NASA’s Armstrong Flight Research Center in Edwards, California, ahead of a calibration flight for a newly installed near-field shock-sensing probe. Mounted on the F-15D, the probe is designed to measure shock waves generated by the X-59 quiet supersonic aircraft during flight. The data will help researchers better understand how shock waves behave in close proximity to the aircraft, supporting NASA’s Quesst mission to enable quiet supersonic flight over land.NASA/Steve Freeman NASA’s F-15D research aircraft conducts a test flight near Edwards, California, with a newly installed near-field shock-sensing probe. Identical to a previously flown version that was intended as the backup, this new probe will capture shock wave data near the X-59 as it flies faster than the speed of sound, supporting NASA’s Quesst mission.NASA/Jim Ross NASA’s F-15D research aircraft conducts a test flight near Edwards, California, with a newly installed near-field shock-sensing probe. Identical to a previously flown version that was intended as the backup, this new probe will capture shock wave data near the X-59 as it flies faster than the speed of sound, supporting NASA’s Quesst mission.NASA/Jim Ross When you’re testing a cutting-edge NASA aircraft, you need specialized tools to conduct tests and capture data –but if those tools need maintenance, you need to wait until they’re fixed. Unless you have a backup. That’s why NASA recently calibrated a new shock-sensing probe to capture shock wave data when the agency’s X-59 quiet supersonic research aircraft begins its test flights.
      When an aircraft flies faster than the speed of sound, it produces shock waves that travel through the air, creating loud sonic booms. The X-59 will divert those shock waves, producing just a quiet supersonic thump. Over the past few weeks, NASA completed calibration flights on a new near-field shock-sensing probe, a cone-shaped device that will capture data on the shock waves that the X-59 will generate.
      This shock-sensing probe is mounted to an F-15D research aircraft that will fly very close behind the X-59 to collect the data NASA needs. The new unit will serve as NASA’s primary near-field probe, with an identical model NASA developed last year acting as a backup mounted to an additional F-15B.
      The two units mean the X-59 team has a ready alternative if the primary probe needs maintenance or repairs. For flight tests like the X-59’s – where data gathering is crucial and operations revolve around tight timelines, weather conditions, and other variables – backups for critical equipment help to ensure continuity, maintain schedule, and preserve efficiency of operations.
      “If something happens to the probe, like a sensor failing, it’s not a quick fix,” said Mike Frederick, principal investigator for the probe at NASA’s Armstrong Flight Research Center in Edwards, California. “The other factor is the aircraft itself. If one needs maintenance, we don’t want to delay X-59 flights.”
      To calibrate the new probe, the team measured the shock waves of a NASA F/A-18 research aircraft. Preliminary results indicated that the probe successfully captured pressure changes associated with shock waves, consistent with the team’s expectations. Frederick and his team are now reviewing the data to confirm that it aligns with ground mathematical models and meets the precision standards required for X-59 flights.
      Researchers at NASA Armstrong are preparing for additional flights with both the primary and backup probes on their F-15s. Each aircraft will fly supersonic and gather shock wave data from the other. The team is working to validate both the primary and backup probes to confirm full redundancy – in other words, making sure that they have a reliable backup ready to go.
      Share
      Details
      Last Updated Apr 17, 2025 EditorDede DiniusContactNicolas Cholulanicolas.h.cholula@nasa.gov Related Terms
      Aeronautics Aeronautics Research Mission Directorate Armstrong Flight Research Center Commercial Supersonic Technology Low Boom Flight Demonstrator Quesst (X-59) Supersonic Flight Explore More
      3 min read NASA Studies Wind Effects and Aircraft Tracking with Joby Aircraft
      Article 20 hours ago 3 min read Testing in the Clouds: NASA Flies to Improve Satellite Data
      Article 2 days ago 3 min read Going Home: NASA Retires S-3B Viking to POW/MIA Museum
      Article 2 days ago Keep Exploring Discover More Topics From NASA
      Armstrong Flight Research Center
      Humans in Space
      Climate Change
      Solar System
      View the full article
    • By NASA
      NASA researchers are sending three air quality monitors to the International Space Station to test them for potential future use on the Moon.Credit: NASA/Sara Lowthian-Hanna As NASA prepares to return to the Moon, studying astronaut health and safety is a top priority. Scientists monitor and analyze every part of the International Space Station crew’s daily life—down to the air they breathe. These studies are helping NASA prepare for long-term human exploration of the Moon and, eventually, Mars.

      As part of this effort, NASA’s Glenn Research Center in Cleveland is sending three air quality monitors to the space station to test them for potential future use on the Moon. The monitors are slated to launch on Monday, April 21, aboard the 32nd SpaceX commercial resupply services mission for NASA.

      Like our homes here on Earth, the space station gets dusty from skin flakes, clothing fibers, and personal care products like deodorant. Because the station operates in microgravity, particles do not have an opportunity to settle and instead remain floating in the air. Filters aboard the orbiting laboratory collect these particles to ensure the air remains safe and breathable.

      Astronauts will face another air quality risk when they work and live on the Moon—lunar dust.
      “From Apollo, we know lunar dust can cause irritation when breathed into the lungs,” said Claire Fortenberry, principal investigator, Exploration Aerosol Monitors project, NASA Glenn. “Earth has weather to naturally smooth dust particles down, but there is no atmosphere on the Moon, so lunar dust particles are sharper and craggier than Earth dust. Lunar dust could potentially impact crew health and damage hardware.”

      Future space stations and lunar habitats will need monitors capable of measuring lunar dust to ensure air filtration systems are functioning properly. Fortenberry and her team selected commercially available monitors for flight and ground demonstration to evaluate their performance in a spacecraft environment, with the goal of providing a dust monitor for future exploration systems.
      NASA Glenn Research Center’s Claire Fortenberry holds a dust sample collected from International Space Station air filters.Credit: NASA/Sara Lowthian-Hanna Glenn is sending three commercial monitors to the space station to test onboard air quality for seven months. All three monitors are small: no bigger than a shoe box. Each one measures a specific property that provides a snapshot of the air quality aboard the station. Researchers will analyze the monitors based on weight, functionality, and ability to accurately measure and identify small concentrations of particles in the air.

      The research team will receive data from the space station every two weeks. While those monitors are orbiting Earth, Fortenberry will have three matching monitors at Glenn. Engineers will compare functionality and results from the monitors used in space to those on the ground to verify they are working as expected in microgravity. Additional ground testing will involve dust simulants and smoke.

      Air quality monitors like the ones NASA is testing also have Earth-based applications. The monitors are used to investigate smoke plumes from wildfires, haze from urban pollution, indoor pollution from activities like cooking and cleaning, and how virus-containing droplets spread within an enclosed space.

      Results from the investigation will help NASA evaluate which monitors could accompany astronauts to the Moon and eventually Mars. NASA will allow the manufacturers to review results and ensure the monitors work as efficiently and effectively as possible. Testing aboard the space station could help companies investigate pollution problems here on Earth and pave the way for future missions to the Red Planet.
      NASA Glenn Research Center’s Claire Fortenberry demonstrates how space aerosol monitors analyze the quality of the air.Credit: NASA/Sara Lowthian-Hanna “Going to the Moon gives us a chance to monitor for planetary dust and the lunar environment,” Fortenberry said. “We can then apply what we learn from lunar exploration to predict how humans can safely explore Mars.”
      NASA commercial resupply missions to the International Space Station deliver scientific investigations in the areas of biology and biotechnology, Earth and space science, physical sciences, and technology development and demonstrations. Cargo resupply from U.S. companies ensures a national capability to deliver scientific research to the space station, significantly increasing NASA’s ability to conduct new investigations aboard humanity’s laboratory in space.
      Learn more about NASA and SpaceX’s 32nd commercial resupply mission to the space station:
      https://www.nasa.gov/nasas-spacex-crs-32/
      Explore More
      3 min read NASA Studies Wind Effects and Aircraft Tracking with Joby Aircraft
      Article 17 hours ago 4 min read Science Meets Art: NASA Astronaut Don Pettit Turns the Camera on Science
      Article 1 day ago 1 min read Recognizing Employee Excellence 
      Article 1 day ago View the full article
    • By European Space Agency
      Image: This very high-resolution image captures the Egyptian city of Giza and its surrounding area, including the world-famous Giza Pyramid Complex. View the full article
  • Check out these Videos

×
×
  • Create New...