Members Can Post Anonymously On This Site
Mysterious satellite captured on camera by ISS crew
-
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
A capacity increase by almost 80%! In late July 2024, the Malargüe deep-space communication station completed an important upgrade of its antenna feed that will allow missions to send much more data back to Earth.
View the full article
-
By European Space Agency
The first IRIDE satellite – the Pathfinder Hawk – is now in orbit around Earth after lifting off on a SpaceX Falcon 9 rocket from the Vandenberg Space Force Base in California on 14 January.
As its ‘Pathfinder’ name suggests, this new microsatellite is a prototype for one of the six IRIDE constellations, which are tailored to provide information for a wide range of environmental, emergency and security services for Italy.
View the full article
-
By USH
The crew of a Surjet private air service flight had an unusual encounter on December 23 while returning to Fort Lauderdale. Flight attendant Cassandra Martin, along with two pilots, was onboard the aircraft flying over the Bahamas when an unexpected event caught their attention.
“I suddenly heard air traffic control say, ‘We have a foreign object; can you please identify it?'” Martin recounted to NBC Miami.
Curious, she looked out the window. “I glanced to the left, and the pilot noticed three objects, though I only saw one. I quickly grabbed my phone, pressed it against the window, and tried to record a video of the object,” she explained.
Martin described the orb as white, later shifting to a faint green hue, almost as though surrounded by an electric field. The object followed their flight for about 45 minutes before disappearing.
What made the sighting extraordinary was the altitude. The jet was cruising at approximately 43,000 to 45,000 feet, yet the orb was far above the aircraft and still managed to track it for the extended duration.
The orb’s speed and maneuverability ruled out possibilities such as a balloon or a consumer drone. Unless the orb is of extraterrestrial origin, the orb might be a craft or drone equipped with highly advanced technology not yet publicly known, akin to recent reports of sophisticated drones spotted across the U.S.
This remarkable incident follows a December 16, 2024 sighting aboard United Airlines flight UA2359 from Chicago to Newark. During that flight, a passenger filmed several unidentified orbs at altitudes between 40,000 and 50,000 feet. Additionally, reports surfaced from at least four commercial airline pilots who witnessed mysterious, colorful, circular lights moving at extreme speeds over Oregon in the same month.
These repeated sightings raise questions: Are they advanced black projects hidden from public knowledge or evidence of something extraterrestrial? Regardless of their origin, the increasing reports of advanced drones and strange orbs suggest that something significant is occurring. View the full article
-
By NASA
Internal view of LignoSat’s structure shows the relationship among wooden panels, aluminum frames, and stainless-steel shafts.Credit: Kyoto University In December 2024, five CubeSats deployed into Earth’s orbit from the International Space Station. Among them was LignoSat, a wooden satellite from JAXA (Japanese Aerospace Exploration Agency) that investigates the use of wood in space. Findings could offer a more sustainable alternative to conventional satellites.
A previous experiment aboard station exposed three species of wood to the space environment to help researchers determine the best option for LignoSat. The final design used 10 cm long honoki magnolia wood panels assembled with a Japanese wood-joinery method.
Researchers will use sensors to evaluate strain on the wood and measure its responses to temperature and radiation in space. Geomagnetic levels will also be monitored to determine whether the geomagnetic field can penetrate the body of the wooden satellite and interfere with its technological capabilities. Investigating uses for wood in space could lead to innovative solutions in the future.
A traditional Japanese wooden joining method, the Blind Miter Dovetail Joint, is used for LignoSat to connect two wooden panels without using glue or nails.Credit: Kyoto University Three CubeSats are deployed from space station, including LignoSat. Keep Exploring Discover More Topics From NASA
Latest News from Space Station Research
Space Station Technology Demonstration
Space Station Research Results
Space Station Research and Technology Resources
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.