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NASA Astronomy Picture of the Day
September 11, 2025
The Umbra of Earth
The dark, inner shadow of planet Earth is called the umbra. Shaped like a cone extending into space, it has a circular cross section most easily seen during a lunar eclipse. And on the night of September 7/8 the Full Moon passed near the center of Earth's umbral cone, entertaining eclipse watchers around much of our fair planet, including parts of Antarctica, Australia, Asia, Europe, and Africa. Recorded from Zhangjiakou City, China, this timelapse composite image uses successive pictures from the total lunar eclipse, progressing left to right, to reveal the curved cross-section of the umbral shadow sliding across the Moon. Sunlight scattered by the atmosphere into Earth's umbra causes the lunar surface to appear reddened during totality. But close to the umbra's edge, the limb of the eclipsed Moon shows a distinct blue hue. The blue eclipsed moonlight originates as rays of sunlight pass through layers high in the upper stratosphere, colored by ozone that scatters red light and transmits blue. In the total phase of this leisurely lunar eclipse, the Moon was completely within the Earth's umbra for about 83 minutes.
https://apod.nasa.gov/apod/astropix.html
NASA bans Chinese nationals from working on programs at facilities
Sept. 11, 2025 / 8:59 AM
NASA has banned Chinese citizens with valid U.S. visas from working on its space programs at its facilities.
NASA said that Chinese nationals would be barred from using its "facilities, materials and networks to ensure the security of our work," after Chinese workers contributing to research were locked out of their IT systems and prevented from attending in-person meetings on Sept. 5.
A NASA press secretary, Bethany Stevens, confirmed that NASA had taken "internal action pertaining to Chinese nationals – including restricting physical and cybersecurity access to our facilities."
Acting NASA Administrator Sean Duffy said the United States and China are currently engaged in "a second space race."
"The Chinese want to get back to the moon before us. That's not going to happen," he said.
"We're in a second space race right now," NASAs acting administrator Sean Duffy said.
Lawmakers stressed the need for the United States to put its footsteps on the moon before China, during a Senate hearing last week.
"China has made no secret of its goals," said Republican senator Ted Cruz. "If our adversaries achieve dominant space capabilities, it would pose a profound risk to America the stakes could not be higher."
By 2027 the United States is planning to land astronauts as part of its Artemis program on the moon.
China has said it's on track to put a person on the moon by 2030. In recent weeks, both countries have proposed a mission to set up a nuclear power plant on the moon by mid-2030.
"The first country to do so could potentially declare a 'keep-out' zone which would significantly inhibit the United States from establishing a planned Artemis presence if not there first," Duffy said.
"We will get to the moon under President Trump's term. Our mission is Artemis. We will win the second space race. China wants to beat us there, but we won't let them."
https://www.upi.com/Science_News/2025/09/11/nasa-bans-chinese-nationals-facilities/7221757593700/
https://www.jpl.nasa.gov/news/nasa-says-mars-rover-discovered-potential-biosignature-last-year/
https://science.nasa.gov/mars/the-mars-report/2025-september-special-edition/
https://science.nasa.gov/mission/mars-2020-perseverance/
NASA Says Mars Rover Discovered Potential Biosignature Last Year
Sept. 10, 2025
After a year’s worth of scientific scrutiny, the ‘Sapphire Canyon’ rock sample remains the mission’s best candidate for containing signs of ancient microbial life processes.
A sample collected by NASA’s Perseverance Mars rover from an ancient dry riverbed in Jezero Crater could preserve evidence of ancient microbial life.
Taken from a rock named “Cheyava Falls” last year, the sample, called “Sapphire Canyon,” contains potential biosignatures, according to a paper published Wednesday in the journal Nature.
A potential biosignature is a substance or structure that might have a biological origin but requires more data or further study before a conclusion can be reached about the absence or presence of life.
“This finding by Perseverance, launched under President Trump in his first term, is the closest we have ever come to discovering life on Mars.
The identification of a potential biosignature on the Red Planet is a groundbreaking discovery, and one that will advance our understanding of Mars,” said acting NASA Administrator Sean Duffy.
“NASA’s commitment to conducting Gold Standard Science will continue as we pursue our goal of putting American boots on Mars’ rocky soil.”
Perseverance came upon Cheyava Falls in July 2024 while exploring the “Bright Angel” formation, a set of rocky outcrops on the northern and southern edges of Neretva Vallis, an ancient river valley measuring a quarter-mile (400 meters) wide that was carved by water rushing into Jezero Crater long ago.
“This finding is the direct result of NASA’s effort to strategically plan, develop, and execute a mission able to deliver exactly this type of science — the identification of a potential biosignature on Mars,” said Nicky Fox, associate administrator, Science Mission Directorate at NASA Headquarters in Washington.
“With the publication of this peer-reviewed result, NASA makes this data available to the wider science community for further study to confirm or refute its biological potential.”
The rover’s science instruments found that the formation’s sedimentary rocks are composed of clay and silt, which, on Earth, are excellent preservers of past microbial life. They also are rich in organic carbon, sulfur, oxidized iron (rust), and phosphorous.
“The combination of chemical compounds we found in the Bright Angel formation could have been a rich source of energy for microbial metabolisms,” said Perseverance scientist Joel Hurowitz of Stony Brook University, New York and lead author of the paper.
“But just because we saw all these compelling chemical signatures in the data didn’t mean we had a potential biosignature. We needed to analyze what that data could mean.”
First to collect data on this rock were Perseverance’s PIXL (Planetary Instrument for X-ray Lithochemistry) and SHERLOC (Scanning Habitable Environments with Raman & Luminescence for Organics & Chemicals) instruments.
While investigating Cheyava Falls, an arrowhead-shaped rock measuring 3.2 feet by 2 feet (1 meter by 0.6 meters), they found what appeared to be colorful spots.
The spots on the rock could have been left behind by microbial life if it had used the raw ingredients, the organic carbon, sulfur, and phosphorus, in the rock as an energy source.
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In higher-resolution images, the instruments found a distinct pattern of minerals arranged into reaction fronts (points of contact where chemical and physical reactions occur) the team called leopard spots.
The spots carried the signature of two iron-rich minerals: vivianite (hydrated iron phosphate) and greigite (iron sulfide).
Vivianite is frequently found on Earth in sediments, peat bogs, and around decaying organic matter. Similarly, certain forms of microbial life on Earth can produce greigite.
The combination of these minerals, which appear to have formed by electron-transfer reactions between the sediment and organic matter, is a potential fingerprint for microbial life, which would use these reactions to produce energy for growth.
The minerals also can be generated abiotically, or without the presence of life. Hence, there are ways to produce them without biological reactions, including sustained high temperatures, acidic conditions, and binding by organic compounds.
However, the rocks at Bright Angel do not show evidence that they experienced high temperatures or acidic conditions, and it is unknown whether the organic compounds present would’ve been capable of catalyzing the reaction at low temperatures.
The discovery was particularly surprising because it involves some of the youngest sedimentary rocks the mission has investigated. An earlier hypothesis assumed signs of ancient life would be confined to older rock formations.
This finding suggests that Mars could have been habitable for a longer period or later in the planet’s history than previously thought, and that older rocks also might hold signs of life that are simply harder to detect.
“Astrobiological claims, particularly those related to the potential discovery of past extraterrestrial life, require extraordinary evidence,” said Katie Stack Morgan, Perseverance’s project scientist at NASA’s Jet Propulsion Laboratory in Southern California.
“Getting such a significant finding as a potential biosignature on Mars into a peer-reviewed publication is a crucial step in the scientific process because it ensures the rigor, validity, and significance of our results.
And while abiotic explanations for what we see at Bright Angel are less likely given the paper’s findings, we cannot rule them out.”
The scientific community uses tools and frameworks like the CoLD scale and Standards of Evidence to assess whether data related to the search for life actually answers the question, Are we alone?
Such tools help improve understanding of how much confidence to place in data suggesting a possible signal of life found outside our own planet.
Sapphire Canyon is one of 27 rock cores the rover has collected since landing at Jezero Crater in February 2021.
Among the suite of science instruments is a weather station that provides environmental information for future human missions, as well as swatches of spacesuit material so that NASA can study how it fares on Mars.
Managed for NASA by Caltech, NASA JPL built and manages operations of the Perseverance rover on behalf of the agency’s Science Mission Directorate as part of NASA’s Mars Exploration Program portfolio.
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moar Perseverance Rover
Perseverance’s PIXL Finds Vivianite, Greigite in ‘Cheyava Falls’ Sample
Sept. 10, 2025
NASA’s Perseverance Mars rover generated this mineral map showing the presence of two minerals — vivianite (purple and pink) and greigite (dull yellow and green) — on the surface of a rock nicknamed “Cheyava Falls.”
The data helped scientists determine the rock contained a potential biosignature, which is a substance or structure that might have a biological origin but requires more data or further study before a conclusion can be reached about the absence or presence of life.
Perseverance’s PIXL (Planetary Instrument for X-ray Lithochemistry) and SHERLOC (Scanning Habitable Environments with Raman & Luminescence for Organics & Chemicals) instruments found a distinct pattern of minerals arranged into reaction fronts (points of contact where chemical and physical reactions occur) that the team called “leopard spots.”
The leopard spots carried the signature of vivianite (hydrated iron phosphate) and greigite (iron sulfide). Vivianite appears within black spots mission scientists refer to as “poppy seeds” and in the dark rims of the larger “leopard spots.”
Greigite is seen within the interiors of the leopard spots, which could have been left behind by microbial life if it had used the raw ingredients — the organic carbon, sulfur, and phosphorus — in the rock as an energy source.
Vivianite is frequently found on Earth in sediments and peat bogs and around decaying organic matter. Similarly, certain forms of microbial life on Earth can produce greigite.
The combination of these minerals, which appear to have formed by electron-transfer reactions between the sediment and organic matter, is a potential “fingerprint” for microbial life, which would use these reactions to produce energy for growth.
The minerals can also be generated abiotically, or without the presence of life.
Managed for NASA by Caltech, JPL built and manages operations of the Perseverance rover on behalf of the agency’s Science Mission Directorate as part of NASA’s Mars Exploration Program portfolio.
The Mars 2020 Perseverance mission is part of NASA’s Mars Exploration Program (MEP) portfolio and the agency’s Moon to Mars exploration approach, which includes Artemis missions to the Moon that will help prepare for human exploration of the Red Planet.
https://www.jpl.nasa.gov/images/pia26640-perseverances-pixl-finds-vivianite-greigite-in-cheyava-falls-sample/
Mastcam-Z imager Aboard the Perseverance Mars Rover
Sept. 10, 2025
The Mastcam-Z imager aboard the Perseverance Mars rover captured this mosaic of “Cheyava Falls” (bottom, right of center) and surrounding rocks on June 22, 2024, the 1187th sol (or Martian day) of the rover’s mission. The mosaic is composed of 108 individual images.
https://www.jpl.nasa.gov/images/mastcam-z-imager-aboard-the-perseverance-mars-rover/
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Map of Mars’ Jezero Crater
Sept. 10, 2025
This map of Mars’ Jezero Crater and vicinity was created by the German Aerospace Center in Berlin, using data from the High-Resolution Stereo Camera (HRSC) aboard the ESA (European Space Agency) Mars Express spacecraft
https://www.jpl.nasa.gov/images/map-of-mars-jezero-crater/
Perseverance’s SHERLOC Finds Organic Molecules in ‘Bright Angel’
Sept. 10, 2025
This graph displays data collected by NASA’s Perseverance Mars rover from targets in a rock formation nicknamed “Bright Angel.”
Scientists later determined one of those targets, a rock nicknamed “Cheyava Falls” (second line from the top), contained a potential biosignature.
A potential biosignature is a substance or structure that might have a biological origin but requires more data or further study before a conclusion can be reached about the absence or presence of life.
The graph includes “G-bands” — a type of signal in Raman spectroscopy — indicating the presence of organic molecules, which can be created by both geological as well as biological sources.
(“Bknd” is shorthand for “background.”) The data was collected by an instrument on the end of Perseverance’s robotic arm called SHERLOC (Scanning Habitable Environments with Raman & Luminescence for Organics & Chemicals).
A key objective for Perseverance’s mission on Mars is astrobiology, including the search for signs of ancient microbial life.
The rover is characterizing the planet’s geology and past climate, to help pave the way for human exploration of the Red Planet, and is the first mission to collect and cache Martian rock and regolith.
The Mars 2020 Perseverance mission is part of NASA’s Mars Exploration Program (MEP) portfolio and the agency’s Moon to Mars exploration approach, which includes Artemis missions to the Moon that will help prepare for human exploration of the Red Planet.
Managed for NASA by Caltech, JPL built and manages operations of the Perseverance rover on behalf of the agency’s Science Mission Directorate as part of NASA’s Mars Exploration Program portfolio.
https://www.jpl.nasa.gov/images/pia26639-perseverances-sherloc-finds-organic-molecules-in-bright-angel/
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Airborne Data Applications for Invasive Species Mapping
Sept. 11, 2025
Invasive species have become an increasing threat to local or endemic species, both in terrestrial and aquatic environments, as they can cause catastrophic impacts on ecosystem health and function.
The occurrence and impacts of invasive species are expected to increase as we face compounding challenges linked with a changing climate, urban expansion, and extreme weather events.
Remote sensing is one tool we can use to monitor and predict future spread of invasive species.
In collaboration with NASA's Oak Ridge National Laboratory Distributed Active Archive Center (ORNL DAAC), NASA's Applied Remote Sensing Training Program (ARSET) is offering a live, advanced online training on September 30, 2025, covering the use of airborne data for invasive species mapping.
Participants will leave with a better understanding of the applications and limitations of imaging spectroscopy and airborne data products.
The skills honed in this training will support participants in their land management and planning decisions.
The no-cost training is open to the public and recommended for experienced resource managers, remote sensing technicians, ecologists, and academics. Register today on the training webpage.
https://www.earthdata.nasa.gov/news/airborne-data-applications-invasive-species-mapping
https://www.earthdata.nasa.gov/learn/trainings/airborne-data-applications-invasive-species-mapping
NASA Uses Colorado Mountains for Simulated Artemis Moon Landing Course
Sep 10, 2025
NASA has certified a new lander flight training course using helicopters, marking a key milestone in crew training for Artemis missions to the Moon.
Through Artemis, NASA explore the lunar South Pole, paving the way for human exploration farther into the solar system, including Mars.
The mountains in northern Colorado offer similar visual illusions and flight environments to the Moon.
NASA partnered with the Colorado Army National Guard at the High-Altitude Army National Guard Aviation Training Site near Gypsum, Colorado, to develop the foundational flight training course.
“Artemis astronauts who will land on the Moon will need to master crew coordination and communication with one another,” said Paul Felker, acting deputy director of flight operations at NASA’s Johnson Space Center in Houston.
“Much like they will on the Moon, astronaut teams are learning how to work together efficiently in a stressful environment to identify hazards, overcome degraded visual environments, and evaluate risks to successfully land.”
During the two-week certification run in late August, NASA astronauts Mark Vande Hei and Matthew Dominick participated in flight and landing training to help certify the course. The pair took turns flying a helicopter and navigating to landing zones.
Artemis flight crew trainers, mission control leads, and lunar lander operational experts from NASA Johnson joined them on each helicopter flight to assess the instruction, training environment, and technical applications for crewed lunar missions.
The NASA astronauts and trained instructor pilots with the Army National Guard flew to progressively more challenging landing zones throughout the course, navigating the mountainous terrain, and working together to quickly and efficiently land the aircraft.
Teams can train year-round using the course. Depending on the season, the snowy or dusty conditions can cause visual obstruction. Lunar dust can cause similar visual impairment during future crewed missions.
“Here in Colorado, we have specifically flown to dusty areas, so we know and understand just how important dust becomes during the final descent phase,” Vande Hei said.
“Dust will interact with the lander thrusters on the Moon. During our flight training, we have had to revert to our instruments – just like we would on the Moon – because astronauts may lose all their visual cues when they’re near the surface.”
During Artemis III, four astronauts inside the agency’s Orion spacecraft on top of the SLS (Space Launch System rocket) will launch to meet SpaceX’s Starship Human Landing System in lunar orbit.
Orion will then dock with the Starship system and two astronauts will board the lander. Astronauts will use the Starship lander to safely transport themselves from lunar orbit to the lunar surface.
Following surface operations, the two astronauts will use Starship to launch from the lunar surface, back to lunar orbit, and dock with Orion to safely journey back to Earth.
The NASA-focused course has been in development since 2021. Vande Hei and Dominick are the 24th and 25th NASA astronauts to participate in and evaluate the course based on functionality and Artemis mission needs.
One ESA (European Space Agency) astronaut has also participated in the course.
“This course will likely be one of the first group flight training opportunities for the Artemis III crew,” said NASA astronaut Doug Wheelock, who helped to develop the foundational training course for the agency.
“While the astronauts will also participate in ground and simulation training in Ohio and Texas, the real-world flight environment in Colorado at offers astronauts an amazing simulation of the problem solving and decision making needed to control and maneuver a lunar lander across an equally dynamic landscape.”
Though the course is now certified for Artemis, teams will continue to evaluate the training based on astronaut and technical feedback to ensure mission success and crew safety.
Through the Artemis campaign, NASA will send astronauts to explore the Moon for scientific discovery, economic benefits, and to build the foundation for the first crewed missions to Mars for the benefit of all.
https://www.nasa.gov/directorates/esdmd/artemis-campaign-development-division/human-landing-system-program/nasa-uses-colorado-mountains-for-simulated-artemis-moon-landing-course/
https://www.youtube.com/watch?v=qBiUXbBMKLU
Biology, Botany Research Advancing Health as Two Resupply Missions Near Launch
September 10, 2025
Scientific operations filled the day for the Expedition 73 crew with a wide variety of research advancing human health on and off the Earth.
Meanwhile, two rockets on opposite sides of the world stand at their launch pads and are counting down to their lift off to resupply the International Space Station.
Doctors on the ground continuously study what happens to a crew member’s body after months of living and working in microgravity.
The voluminous data is measured and collected almost constantly revealing the physical and mental changes an astronaut goes through during the course of a long-term spaceflight.
The insights help doctors develop numerous countermeasures to protect crews as NASA and its international partners plan longer missions farther away from Earth to the Moon, Mars, and beyond.
Cardiovascular health in space is a key research topic for scientists studying how the lack of gravity affects an astronaut’s blood flow.
NASA Flight Engineer Zena Cardman on Wednesday wore chest electrodes and scanned her leg arteries with an ultrasound device as medical experts from Canada, France, and the U.S. remotely guided the operations.
The doctors were looking for signs of space-caused arterial stiffness and changes in cardiac function for the CIPHER human research investigation using the Vascular Echo hardware.
Cardman later partnered with NASA Flight Engineer Jonny Kim and studied how bone stem cells, recently delivered aboard a SpaceX Dragon cargo craft, adapt to microgravity.
The duo took turns processing the cell samples in the Destiny laboratory module’s Microgravity Science Glovebox before stowing them inside a science freezer for future analysis.
Doctors will use the data gleaned from the experiment to learn how to protect an astronaut’s skeletal system in space and treat aging conditions and bone diseases on Earth.
NASA Flight Engineer Mike Fincke explored ways to produce vitamins and nutrients on spacecraft helping supply adequate nutrition for crews on space missions without reliance on cargo missions launched from Earth.
He treated yeast, yogurt, and fermented milk samples then installed them in a research incubator for the BioNutrients-3 investigation seeking to create a biomanufacturing facility to help sustain future space crews.
Another way to sustain and nourish crews too far away from Earth to be resupplied is to grow crops in spaceships or space habitats.
Flight Engineer Kimiya Yui of JAXA (Japan Aerospace Exploration Agency) explored space botany studying how plant cells divide in microgravity.
He first processed algae cell samples retrieved from a research incubator then stowed them inside a science freezer for future treatment.
The cell samples will be imaged inside JAXA’s COSMIC fluorescent microscope to visualize microgravity’s effect on plant cell division and microstructures.
Understanding how weightlessness affects plant growth may lead to food crop production techniques on missions to the Moon and Mars.
Station Commander Sergey Ryzhikov and Flight Engineer Alexey Zubritsky, both Roscosmos cosmonauts, joined each other in the Nauka science module configuring physics research gear to study advanced space propulsion systems and plasma-based technologies.
Flight Engineer Oleg Platonov started his shift in the Zarya module replacing electronic power components before an afternoon Earth photography session imaging glaciers in South America and mountains in Africa.
Roscosmos’ Progress 93 spacecraft, packed with 2.8 tons of food, fuel, and supplies, sits atop a Soyuz rocket at its launchpad at the Baikonur Cosmodrome in Kazakhstan counting down to a liftoff at 11:54 a.m. EDT on Thursday.
It will orbit Earth for two days before docking to the Zvezda service module at 1:27 p.m. on Saturday where it will stay for six months.
Just one day after the Progress 93’s arrival, Northrop Grumman’s Cygnus XL resupply ship will launch atop a SpaceX Falcon 9 rocket at 6:11 p.m. on Sunday, Sept. 14, from Florida’s Cape Canaveral Space Force Station.
Cygnus will deliver over 11,000 pounds of new science experiments and station hardware to the orbital outpost. Kim, assisted by Cardman, will be at the cupola’s robotics workstation commanding the Canadarm2 robotic arm to capture the spacecraft at 6:35 a.m. on Wednesday, Sept. 17.
Ground controllers will then take over and remotely command Canadarm2 to install Cygnus to the Unity module’s Earth-facing port about an hour-and-a-half later for a six-month stay.
https://www.nasa.gov/blogs/spacestation/2025/09/10/biology-botany-research-advancing-health-as-two-resupply-missions-near-launch/
NASA Invites Media to View Artemis Moon Rocket, Spacecraft at Kennedy
Sep 10, 2025
Media are invited to see NASA’s fully assembled Artemis II SLS (Space Launch System) rocket and Orion spacecraft in mid-October before its crewed test flight around the Moon next year.
The event at NASA’s Kennedy Space Center in Florida will showcase hardware for the Artemis II lunar mission, which will test capabilities needed for deep space exploration.
NASA and industry subject matter experts will be available for interviews.
Attendance is open to U.S. citizens and international media. Media accreditation deadlines are as follows:
International media without U.S. citizenship must apply by 11:59 p.m. EDT on Monday, Sept. 22.
U.S. media and U.S. citizens representing international media organizations must apply by 11:59 p.m. EDT on Monday, Sept. 29.
Media wishing to take part in person must apply for credentials at:
https://media.ksc.nasa.gov
Credentialed media will receive a confirmation email upon approval, along with additional information about the specific date for the mid-October activities when they are determined.
NASA’s media accreditation policy is available online. For questions about accreditation, please email: ksc-media-accreditat@mail.nasa.gov. For other questions, please contact the NASA Kennedy newsroom at: 321-867-2468.
Prior to the media event, the Orion spacecraft will transition from the Launch Abort System Facility to the Vehicle Assembly Building at NASA Kennedy, where it will be placed on top of the SLS rocket.
The fully stacked rocket will then undergo complete integrated testing and final hardware closeouts ahead of rolling the rocket to Launch Pad 39B for launch.
During this effort, technicians will conduct end-to-end communications checkouts, and the crew will practice day of launch procedures during their countdown demonstration test.
Artemis II will send NASA astronauts Reid Wiseman, Victor Glover, Christina Koch, and CSA (Canadian Space Agency) astronaut Jeremy Hansen on an approximately 10-day journey around the Moon and back.
As part of a Golden Age of innovation and exploration, Artemis will pave the way for new U.S.-crewed missions on the lunar surface ahead in preparation toward the first crewed mission to Mars.
To learn more about the Artemis II mission, visit:
https://www.nasa.gov/mission/artemis-ii
https://www.nasa.gov/news-release/nasa-invites-media-to-view-artemis-moon-rocket-spacecraft-at-kennedy/
https://science.nasa.gov/earth/nasa-data-trainings-help-uruguay-navigate-drought/
NASA Data, Trainings Help Uruguay Navigate Drought
Sep 10, 2025
NASA satellite data and trainings helped Uruguay create a drought-response tool that its National Water Authority now uses to monitor reservoirs and guide emergency decisions.
A similar approach could be applied in the United States and other countries around the world. From 2018 to 2023, Uruguay experienced its worst drought in nearly a century.
The capital city of Montevideo, home to nearly 2 million people, was especially hard hit. By mid-2023, Paso Severino, the largest reservoir and primary water source for Montevideo, had dropped to just 1.7% of its capacity.
As water levels declined, government leaders declared an emergency. They began identifying backup supplies and asked: Was there water left in other upstream reservoirs — mainly used for livestock and irrigation — that could help?
That’s when environmental engineer Tiago Pohren and his colleagues at the National Water Authority (DINAGUA - Ministry of Environment) turned to NASA data and trainings to build an online tool that could help answer that question and improve monitoring of the nation’s reservoirs.
“Satellite data can inform everything from irrigation scheduling in the Great Plains to water quality management in the Chesapeake Bay,” said Erin Urquhart, manager of the water resources program at NASA Headquarters in Washington.
“NASA provides the reliable data needed to respond to water crises anywhere in the world.”
Learning to Detect Water from Space
The DINAGUA team learned about NASA resources during a 2022 workshop in Buenos Aires, organized by the Interagency Science and Applications Team (ISAT).
Led by NASA, the U.S. Army Corps of Engineers, and the U.S. Department of State, the workshop focused on developing tools to help manage water in the La Plata River Basin, which spans multiple South American countries including Uruguay.
At the workshop, researchers from NASA introduced participants to methods for measuring water resources from space. NASA’s Applied Remote Sensing (ARSET) program also provided a primer on remote sensing principles.
“NASA doesn’t just deliver data,” said John Bolten, NASA’s lead scientist for ISAT and chief of the Hydrological Sciences Laboratory at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.
“We collaborate with our partners and local experts to translate the data into information that is useful, usable, and relevant. That kind of coordination is what makes NASA’s water programs so effective on the ground, at home and around the world.”
The DINAGUA team brought ideas and provided guidelines to Pohren for a tool that applies Landsat and Sentinel satellite imagery to detect changes in Uruguay’s reservoirs.
Landsat, a joint NASA-U.S. Geological Survey mission, provides decades of satellite imagery to track changes in land and water.
The Sentinel missions, a part of the European Commission managed Copernicus Earth Observation program and operated by ESA (the European Space Agency), provide complementary visible, infrared, and microwave imagery for surface water assessments.
From a young age, Pohren was familiar with water-related challenges, as floods repeatedly inundated his relatives’ homes in his hometown of Montenegro, Brazil.
It was extra motivation for him as he scoured ARSET tutorials and taught himself to write computer code. The result was a monitoring tool capable of estimating the surface area of Uruguay’s reservoirs over time.
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The tool draws on several techniques to differentiate the surface water extent of reservoirs. These techniques include three optical indicators derived from the Landsat 8 and Sentinel-2 satellites:
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Normalized Difference Water Index, which highlights water by comparing how much green and near-infrared light is reflected. Water absorbs infrared light, so it stands out clearly from land.
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Modified Normalized Difference Water Index, which swaps near-infrared with shortwave infrared to improve the contrast and reduce errors when differentiating between water and built-up or vegetated areas.
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Automated Water Extraction Index, which combines four types of reflected light — green, near-infrared, and two shortwave infrared bands — to help separate water from shadows and other dark features.
From Emergency Tool to Everyday Asset
In 2023, the DINAGUA team used Pohren’s tool to examine reservoirs located upstream from Montevideo’s drinking water intake. But the data told a tough story.
“There was water available in other reservoirs, but it was a very small amount compared to the water demand of the Montevideo metropolitan region,” Pohren said.
Simulations showed that even if all of the water were released, most of it would not reach the water intake for Montevideo or the Paso Severino reservoir.
Despite this news, the analysis prevented actions that might have wasted important resources for maintaining productive activities in the upper basin, Pohren said.
Then, in August 2023, rain began to refill Uruguay’s reservoirs, allowing the country to declare an end to the water crisis.
Though the immediate water crisis has passed, the tool Pohren created will be useful in the future in Uruguay and around the world.
During an ISAT workshop in 2024, he shared his tool with international water resources managers with the hope it could aid their own drought response efforts.
And DINAGUA officials still use it to identify and monitor dams, irrigation reservoirs, and other water bodies in Uruguay.
Pohren continues to use NASA training and data to advance reservoir management.
He’s currently exploring an ARSET training on how the Surface Water and Ocean Topography (SWOT) mission will further improve the system by allowing DINAGUA to directly measure the height of water in reservoirs.
He is also following NASA’s new joint mission with ISRO (the Indian Space Research Organization) called NISAR, which launched on July 30.
The NISAR satellite will provide radar data that detects changes in water extent, regardless of cloud cover or time of day.
“If a drought happens again,” Pohren said, “with the tools that we have now, we will be much more prepared to understand what the conditions of the basin are and then make predictions.”
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