Members Can Post Anonymously On This Site
-
Similar Topics
-
By NASA
NASA’s Jet Propulsion Laboratory used radar data taken by ESA’s Sentinel-1A satellite before and after the 2015 eruption of the Calbuco volcano in Chile to create this inter-ferogram showing land deformation. The color bands west of the volcano indicate land sinking. NISAR will produce similar images.ESA/NASA/JPL-Caltech A SAR image — like ones NISAR will produce — shows land cover on Mount Okmok on Alaska’s Umnak Island . Created with data taken in August 2011 by NASA’s UAVSAR instrument, it is an example of polarimetry, which measures return waves’ orientation relative to that of transmitted signals.NASA/JPL-Caltech 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 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.”
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
Share
Details
Last Updated Jan 21, 2025 Related Terms
NISAR (NASA-ISRO Synthetic Aperture Radar) Earth Earth Science Earth Science Division Jet Propulsion Laboratory Explore More
4 min read NASA Scientists, Engineers Receive Presidential Early Career Awards
Article 4 days ago 6 min read NASA International Space Apps Challenge Announces 2024 Global Winners
Article 5 days ago 3 min read NASA Scientists Find New Human-Caused Shifts in Global Water Cycle
Article 5 days ago Keep Exploring Discover More Topics From NASA
Missions
Humans in Space
Climate Change
Solar System
View the full article
-
By European Space Agency
Image: This Copernicus Sentinel-2 image captures the borders between North and South Dakota and Minnesota blanketed with snow and ice. View the full article
-
By NASA
NASA has selected Mary Beth Schwartz as director of NASA’s Johnson Space Center Center Operations directorate. Schwartz previously served as the directorate’s deputy director.
“I’m excited to embark on my new role as director for Johnson’s Center Operations directorate,” Schwartz said. “It is an honor to lead an organization that is foundational to the center’s mission success.”
Ms. Schwartz began her NASA career as a NASA intern and has since held a variety of key roles. These include serving as a space shuttle flight controller, chair of the PSRP (Payload Safety Review Panel) for both the International Space Station and Space Shuttle programs, where she led establishment of PSRP franchises with international partners. She also served as the manager of the Safety and Mission Assurance business office, leading efforts in consolidation and budget integration, and as the associate director of Johnson engineering responsible for budget and facility functions.
Throughout her career, Schwartz has been recognized for her contributions to NASA, receiving the NASA Exceptional Service medal, as well as the NASA Honor and Silver Snoopy awards.
“Mary Beth has a unique perspective of Center Operations, not only as a mission and customer-focused organization, but as an organization that is key to employee experience,” said Vanessa Wyche, director of NASA’s Johnson Space Center. “I appreciate her vision for the organization, commitment to the mission, and overall genuine respect of the workforce. I am extremely pleased to announce her selection for this position.”
Ms. Schwartz earned her Bachelor of Science in Mechanical Engineering from the University of Houston.
View the full article
-
By NASA
If you ask Johnson Space Center employees why they work for NASA, many will tell you it was always their dream. For others, landing a job at NASA was an unexpected stop on their career path. Here is a look at where five Johnson team members worked before NASA and how they are helping to advance the agency’s mission today.
Michelle Wood
How it started: Michelle Wood working as an American Sign Language interpreter (left). How it’s going: Wood as a flight controller in Johnson Space Center’s Mission Control Center in Houston. Images courtesy of Wood Wood worked as an American Sign Language interpreter before joining NASA about seven years ago. Today, she is an Operational Support Officer flight controller and instructor in the Mission Control Center.
***
Warnecke Miller
How it started: Miller is shown completing firearms training as a Federal Bureau of Investigation intern in the summer of 1998 (left). How it’s going: Miller emceeing a retirement celebration for a Johnson colleague in April 2024. Images courtesy of Miller Miller has been an attorney in Johnson’s Office of the General Counsel for 12 years. Before that, she served as an administrative law judge for Social Security and adjudicated disability cases.
***
Celeste Budwit-Hunter
How it started: Celeste Budwit-Hunter is pictured as a school counselor (left). How it’s going: Budwit-Hunter with NASA astronauts Mike Finke, Suni Williams, and Butch Wilmore and her Procedures Group editorial team members in Johnson’s Space Vehicle Mockup Facility. Images courtesy of Budwit-Hunter Budwit-Hunter was a technical writer in the oil and gas industry before earning a master’s degree in family therapy. She went on to work for The Council on Alcohol and Drugs (now The Council on Recovery) and then as a private school counselor for students with learning disabilities. She returned to technical writing while starting a private family therapy practice. After several years of treatment and recovery following a cancer diagnosis, Budwit-Hunter applied to become an editor in the Flight Operations Director’s Procedures Group. She is now the group’s lead editor and is training to become a book manager.
***
Don Walker
How it started: A photo of a young Don Walker standing in front of an Apollo lunar module mockup on the Johnson campus in the early 1970s (left). How it’s going: Walker’s official NASA portrait. Walker worked as a freelancer in television production before joining the Johnson team 38 years ago. Today, Walker is an engineering technician in the Office of the Chief Information Officer, working master control for the center’s television operations.
***
Donna Coyle
How it started: Donna Coyle as a college student in Rome (left). How it’s going: Coyle outside Space Center Houston prior to the Expedition 68 crew debrief and awards ceremony in 2023. Images courtesy of Coyle Coyle earned a bachelor’s degree in international relations before switching gears to work as an expeditor in the oil and gas industry. That role involved working with cross-functional teams to ensure the smooth and timely delivery of equipment and materials to worksites. After visiting locations and seeing how equipment, piping, and steel were made, she was inspired to go back to school to become an engineer. Coyle’s grandfather worked at NASA during the Apollo missions, and she decided to follow in his footsteps. She joined the Johnson team in 2021 as a crew time engineer, analyzing astronaut time as a resource to help with decision-making before and during expeditions to the International Space Station.
Do you want to join the NASA team? Visit our Careers site to explore open opportunities and find your place with us!
View the full article
-
By NASA
NASA On April 21, 1972, NASA astronaut John W. Young, commander of the Apollo 16 mission, took a far-ultraviolet photo of Earth with an ultraviolet camera. Young’s original black-and-white picture was printed on Agfacontour professional film three times, with each exposure recording only one light level. The three light levels were then colored blue (dimmest), green (next brightest), and red (brightest), resulting in the enhanced-color image seen here.
Dr. George Carruthers, a scientist at the Naval Research Laboratory, developed the ultraviolet camera – the first Moon-based observatory – for Apollo 16. Apollo 16 astronauts placed the observatory on the Moon in April 1972, where it sits today on the Moon’s Descartes highland region, in the shadow of the lunar module Orion.
Image credit: NASA
View the full article
-
-
Check out these Videos
Recommended Posts
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.