Last November, NASA and its European partners launched the Sentinel-6B satellite to improve hurricane forecasts, help protect infrastructure, and benefit commercial industries, including shipping. The satellite now is flying 30 seconds behind its predecessor, Sentinel-6 Michael Freilich. Both satellites are providing precise sea level height measurements during what oceanographers expect to be a historic El Niño, a naturally occurring oceanic phenomenon in which warmer-than-usual Pacific waters shift global weather patterns.

The two satellites make up the Copernicus Sentinel-6/Jason-CS (Continuity of Service) mission, the latest in a series of ocean-observing radar altimetry missions that have been monitoring Earth’s changing seas continuously since the early 1990s.

The data each satellite is collecting will not only allow scientists to better understand this year’s El Niño but will also help them create more accurate hurricane predictions.

“This El Niño was a late-bloomer,” said Josh Willis, Sentinel-6B’s project scientist at NASA’s Jet Propulsion Laboratory in Southern California. “It didn’t kick off until the middle of the year and is just now reaching a strength similar to what we’ve seen in the satellite record during significant El Niños in 1997 and 2015. We expect it to be big, and it’s already having big impacts.”

El Niños generally scramble weather patterns tied to rainfall and storms, including hurricanes. They also redistribute heat in the ocean, which affects sea level. Normally, Earth’s warmest ocean waters sit along the equator in the western Pacific. During El Niño, weakened winds, which usually blow westward along the equator, result in heat spreading east toward South America. The change in ocean heat shifts hurricane activity from the Atlantic to the Pacific Ocean.

Predicting hurricane strength

On July 15, Sentinel-6B began delivering low-latency data to scientists that could be used for weather predictions. That data will take some time to work its way into the research models on which meteorologists and climate scientists rely, but when it does, those improved models could save lives.

Data from Sentinel-6 satellite missions feeds into hurricane tracking algorithms used by federal and state agencies. Those predictions can activate disaster response efforts, mobilizing resources ranging from sandbag placement to National Guard activation. They also can lead to evacuation orders that require quick but well-informed decisions about logistics at a local level. More severe events may require engaging larger organizations, such as the Federal Emergency Management Agency.

A tropical storm can take a week or more to become a hurricane and make its way to a coastline, but a hurricane can rapidly intensify in the 48 hours prior to landfall, leaving planners little time to prepare.

“Hurricanes have been known to speed up quickly at the last moment, so the window in which to decide what to do is short,” said Deirdre Byrne, an oceanographer and altimetry expert with the National Oceanic and Atmospheric Administration (NOAA). “The goal is to forecast how much and how rapidly intensification will happen so that officials can make the right calls.”

Byrne oversees one of the country’s most crucial hurricane forecasting algorithms, NOAA’s Satellite Ocean Heat Content Suite, which has been operating since 2012.

Each Sentinel-6 satellite measures ocean height, as well as the size of waves and marine wind speed, using a radar altimeter, which bounces thousands of radar pulses a second off the crests and troughs of waves. Ocean height varies from place to place and provides insight into the ocean’s heat content, since warm water expands. That, in turn, helps forecast how fast hurricanes will grow.

The satellites each carry a second instrument, called the Global Navigation Satellite System – Radio Occultation (GNSS-RO), which measures atmospheric properties, such as humidity, pressure, and temperature.

Among the measurements Sentinel-6 is gathering, Byrne is most anticipating the ocean height data, which she plans to begin incorporating into the current Satellite Ocean Heat Content Suite algorithm by the end of the year.

“In terms of data quality, the Sentinel-6 missions are unparalleled,” Byrne said.

Together, the missions are also extending a precise dataset deep into its fourth decade. This record of sea level observations traces back to the TOPEX/Poseidon mission, which launched in 1992, and continues through to the present day with Sentinel-6 Michael Freilich. Sentinel-6B will take over for its predecessor as the reference satellite for global sea level measurements later this year.

“The key is consistency, measuring the same way, every time,” said Severine Fournier, Sentinel-6B deputy project scientist, JPL. “That’s what lets us predict hurricanes, and, in turn, protect coastal communities and infrastructure.”

More about Sentinel-6B

Sentinel-6 Michael Freilich, named after a former director of NASA’s Earth Science Division, is one of two satellites that compose the Copernicus Sentinel-6/Jason-CS mission.

Sentinel-6/Jason-CS, a part of the European Union’s Earth observation program called Copernicus, was jointly developed by ESA (European Space Agency), EUMETSAT (European Organisation for the Exploitation of Meteorological Satellites), NASA, and NOAA, with funding support from the European Commission and technical support on performance from the French space agency CNES (Centre National d’Études Spatiales). Spacecraft monitoring and control, as well as the processing of all the altimeter science data, is carried out by EUMETSAT on behalf of the European Union’s Copernicus Programme, with the support of all partner agencies.

NASA JPL, a division of Caltech in Pasadena, contributed three science instruments for each Sentinel-6 satellite: the Advanced Microwave Radiometer, the GNSS-RO, and the Laser Retroreflector Array. NASA also contributed launch services, ground systems supporting operation of the agency’s science instruments, the science data processors for two of these instruments, and support for the United States members of the international Ocean Surface Topography Science Team.

For more about Sentinel-6B, visit:

https://science.nasa.gov/mission/sentinel-6B

-end-

Media Contacts

Andrew Good / Andrew Wang
Jet Propulsion Laboratory, Pasadena, Calif.
818-393-2433 / 626-379-6874
andrew.c.good@jpl.nasa.gov / andrew.wang@jpl.nasa.gov

2026-060

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Pandora, NASA’s newest exoplanet mission and the first satellite to launch through the agency’s Astrophysics Pioneers program, is now making unique observations of worlds beyond our solar system and the stars they orbit. The mission will determine the atmospheric make-up of at least 20 exoplanets, including the presence of hazes, clouds, and water.

“Pandora’s data will help close a major gap in our knowledge about planets and their host stars because, right now, we can’t be entirely sure how the star’s light affects measurements of what makes up exoplanet atmospheres,” said Elisa Quintana, Pandora’s principal investigator at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “We designed the Pandora spacecraft and its in-depth observing program to better understand this vexing issue.”

The results of the mission will lay a firm foundation for interpreting measurements by NASA’s James Webb Space Telescope, as well as future observatories focused on finding habitable worlds. In fact, Pandora’s near-infrared detector is a spare originally developed for Webb.

“The spacecraft is healthy and all of the instruments are performing as well as we could have hoped,” said Jordan Karburn, Pandora’s deputy project manager at Lawrence Livermore National Laboratory in California. “Our team’s hard work throughout the commissioning process has paid off, and we can now confidently start science.”

Launched into low Earth orbit on Jan. 11, Pandora is an ambitious small satellite (SmallSat) funded by NASA’s Astrophysics Pioneers program. Pioneers are designed to explore compelling questions about the universe with fast-paced, low-cost missions that require a higher-than-usual tolerance for failure. 

Three factors make Pandora unique. It carries a novel all-aluminum telescope about 18 inches (45 centimeters) in diameter, it will study planets and their host stars simultaneously in both visible and infrared light, and it will observe targets for a much longer time than flagship observatories like Webb are able to.

Telescopes can sample a planet’s atmosphere in systems where the planet passes in front of its star as seen from our perspective. During this event, called a transit, some starlight skims the planet’s atmosphere before making its way to us. As this light interacts with atmospheric molecules, their chemical fingerprints become embedded in it. For each molecule, astronomers see brightness dips at characteristic wavelengths. 

But our instruments also see light from the whole star, not just what grazes the planet. Stellar surfaces aren’t uniform. They sport hotter, brighter areas called faculae and cooler, darker regions similar to sunspots. Both can grow, shrink, and change position as the star rotates.

“Water is one of the most important molecules we can measure to understand the composition and physical conditions of an exoplanet atmosphere,” said Benjamin Rackham, a team member at the Massachusetts Institute of Technology in Cambridge. “But features on the star can distort the water signal we’re searching for. Pandora is designed to disentangle the signals from the planet and the star, helping us to understand the planets more accurately and laying the groundwork for the eventual study of planets that could harbor life.”

Pandora’s telescope, jointly developed by Livermore and Corning Specialty Materials in Keene, New Hampshire, and its detectors make up the mission’s heart. The detectors will capture the star’s brightness in visible light and its near-infrared spectrum at the same time, while also obtaining a near-infrared spectrum from the planet when it transits the star. Over the course of its year-long primary mission, Pandora will observe at least 20 exoplanets 10 times with a long-duration stare covering 24 hours, with a transit included in each observation.

“Pandora’s advantage is its ability to observe targets for extended periods at multiple wavelengths, something high-demand flagship missions like Webb cannot regularly do,” said Knicole Colón, the mission’s project scientist at NASA Goddard. “Combining Pandora and Webb data will uniquely enable scientists to determine the properties of stellar surfaces and cleanly separate star and planetary signals.”

Pandora is led by NASA’s Goddard Space Flight Center. Lawrence Livermore National Laboratory provides the mission’s project management and engineering. Pandora’s telescope was manufactured by Corning and developed collaboratively with Livermore, which also developed the imaging detector assemblies, the mission’s control electronics, and all supporting thermal and mechanical subsystems. The infrared sensor was provided by NASA Goddard. Blue Canyon Technologies provided the bus, performed spacecraft assembly, integration and environmental testing, and is providing mission operations support. NASA’s Ames Research Center in California’s Silicon Valley performs the mission’s data processing. Pandora’s science data is available at the NASA Exoplanet Archive, which is operated by IPAC at the California Institute of Technology in Pasadena. The University of Arizona leads mission operations for Pandora and contributes to its science program. Many additional universities also support the science team.

To learn more about the Pandora mission, please visit:

https://science.nasa.gov/mission/pandora/

As the effects of the 2026 snow drought in the western United States carry into summer, NASA Earth data is feeding machine-learning forecasts that inform decisions about water, power, and public safety in Washington state.  

Tacoma Power, a Washington public utility, is using a U.S. technology company’s river-flow forecasts during a year of water extremes on the Cowlitz River. The utility’s largest hydroelectric project uses water stored behind Mayfield and Mossyrock dams to generate enough electricity to serve more than 151,000 homes each year.

Upstream Tech’s HydroForecast combines weather forecasts and river measurements with NASA-produced satellite data on snow cover and vegetation conditions to predict river flow from hours to days ahead. Updated every two hours, the forecasts are used by reservoir managers, hydropower producers, water utilities, and government agencies to prepare for storms, plan reservoir water releases, and navigate dry periods.

“Part of NASA’s mission is to make the view from space useful on the ground,” said Erin Urquhart, manager for NASA’s Water Resources program at the agency’s headquarters in Washington, D.C. “When an American company incorporates NASA’s freely available data into forecasts that help water managers prepare for floods, generate power, and steward water supplies, that’s NASA delivering practical value to the nation.”

Year of water extremes

During the winter of 2025-26, unusual warmth meant a larger share of precipitation fell as rain instead of snow across much of the West, while below-normal precipitation deepened deficits in some areas. January, February, and March each had the lowest Western snow cover for that month in the NASA MODIS (Moderate Resolution Imaging Spectroradiometer) satellite record since 2001.

On the Cowlitz, those conditions produced a season of extremes. In December 2025, a powerful atmospheric river brought a long, narrow band of Pacific moisture into the region, causing one of the largest one-day inflow surges ever recorded at Tacoma Power’s hydroelectric project. Across the season, that rain-heavy pattern sent water downstream quickly instead of building mountain snowpack that would melt and release water steadily into summer. Snowpack remained at just 20% to 50% of normal levels.

As winter became spring, the rain tapered off, and on April 8, Washington state placed every watershed, including the Cowlitz, under a drought emergency. From April through June, peak daily inflow into the project was among the lowest on record, leaving Tacoma Power with less incoming water to replenish its reservoirs ahead of summer demand, said Saul Villarreal, Tacoma Power’s senior hydro operations manager.

Turning satellite data into river forecasts

NASA turns observations collected by the VIIRS (Visible Infrared Imaging Radiometer Suite) instrument on the Suomi-NPP (Suomi National Polar-orbiting Partnership) satellite into data products that provide information about snow cover and vegetation greenness across entire watersheds, including where ground monitors are sparse.

To train HydroForecast, Upstream Tech collects and archives years of those NASA products alongside weather forecast data and actual river-flow measurements. Using records from hundreds of watersheds, the models learn common patterns in how water moves through the landscape and apply them in new locations.

Tests across multiple basins found that including snow and vegetation observations increased forecast skill, said Dr. Laura Read, director of technical and federal partnerships for HydroForecast at Upstream Tech. “NASA’s data gives us the reliability, global coverage, and consistency we need,” said Read. “Our short-term models run every two hours, so those inputs have to show up when we need them. Though we have stopgaps in place, any interruption to our operational pipeline is a huge deal.”

Tacoma Power uses HydroForecast alongside stream gauges, snow stations, and operator judgment. During the December storm, the NASA-informed, short-term forecast helped the utility anticipate how much water would reach the project and prepare for dynamic river conditions, while meeting operating requirements and keeping public safety at the forefront, Villarreal said.

As spring approached, the operational challenge reversed. Tacoma Power used HydroForecast’s seasonal model to track the growing risk of weak runoff and began keeping its reservoirs higher than usual to preserve water for summer. That left less space to contain another large storm, so operators continued checking the short-term forecast “to play defense,” and remained ready to adjust operations if another atmospheric river developed.

“The earlier we understand how conditions might change, the more effective planning we can do to manage our reservoir and balance the many demands of our system throughout the season,” said Villarreal.

Tacoma Power entered summer 2026 with reservoir levels near average despite the dry spring. The stored water supports reliable hydropower, required river flows to support fish and aquatic habitat, and public recreation. It also gives the utility more flexibility to meet electricity demand during heat waves or unexpected outages and, when possible, support the wider regional power system.

From forecasts to drought assessments

Tacoma Public Utilities’ Cowlitz Hydro Project is just one example of NASA science supporting water decisions across the West.

NASA also has partnered with the U.S. Department of Agriculture’s Natural Resources Conservation Service to bring satellite-based snow and groundwater information into machine-learning water-supply forecasts.

The National Oceanic and Atmospheric Administration’s Colorado Basin River Forecast Center uses MODIS and VIIRS data to adjust snowmelt rates in its model. The Bureau of Reclamation uses NASA and NASA-derived snow data, alongside other sources, for reservoir operations in California’s San Joaquin Basin.

NASA data and research have long informed the U.S. Drought Monitor, the weekly assessment used by farmers, water managers, and public agencies. NASA became a formal partner in 2026, expanding its role from providing information to helping produce the assessment. The agency took its first turn authoring the Drought Monitor during the week of Aug. 17.

About the Author

Emily DeMarco

Writer/Editor (IV), Earth Science Division

Emily is a science writer and editor with NASA’s Earth Science Division, with more than 10 years of experience in science journalism and communication. A former deputy news editor at the magazine Science News, she holds a master’s in environmental science and management from UC Santa Barbara’s Bren School, where she specialized in water resources management and science communication.

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A NASA-funded air pollution monitoring network has provided one of the most detailed long-term views yet of the role of black carbon, or soot produced by fires, diesel vehicles, and other combustion sources, in Ethiopia’s capital, Addis Ababa. The detailed measurements show how pollution changes by time of day and season, including increases associated with rush-hour traffic and holiday celebrations. The findings are relevant to cities around the world, including in the United States.

In a new paper published in ES&T: Air, scientists analyzed data collected throughout Addis Ababa between 2022 and 2025 from 10 air-quality monitoring sites deployed by NASA’s Multi-Angle Imager for Aerosols (MAIA) project.

The research comes as Ethiopia is taking steps aimed at improving air quality. In 2024, the country became the first in the world to ban the import of internal combustion engine vehicles, while cities have been adding bike lanes and electric vehicle infrastructure. The MAIA project’s measurements provide researchers with a baseline for understanding how air quality changes over time as Addis Ababa continues to grow and evolve.

The study focuses on particulate matter that is 2.5 micrometers or less in diameter, also known as PM2.5. The 2025 State of Global Air Report, cited in the paper, estimates that exposure to PM2.5 is associated with approximately 4.9 million deaths globally each year. Among the many kinds of PM2.5, black carbon has been has been studied for its potential effects on human health.

The paper found that Addis Ababa’s three-year average PM2.5 concentration was 30 micrograms per cubic meter, which is more than three times the level of the U.S. Environmental Protection Agency’s health-based annual PM2.5 standard. The new paper cites data from MAIA’s ground sensors indicating that average black carbon levels in Addis Ababa were approximately four to nine times higher than those measured in the three U.S. metropolitan areas the mission is monitoring.

“To our knowledge, this is the first long-term, multisite study of continuous PM2.5 and black carbon measurements in Ethiopia,” said Sina Hasheminassab, a coauthor of the paper and MAIA’s deputy principal investigator at NASA’s Jet Propulsion Laboratory in Southern California. “Many rapidly growing cities have limited long-term monitoring, so these measurements provide an important baseline for understanding how pollution changes across space and time.”

The composition and sources of PM2.5 can differ substantially between cities, depending on their local geography, traffic, industries, and more. Desert cities, for example, may have more dust, while those near coal-fired power plants may have higher concentrations of sulfate. Long-term surface measurements remain limited in many parts of the world.

NASA is supporting MAIA’s air pollution research in a dozen metropolitan areas around the globe, including three in the U.S.: Los Angeles, Atlanta, and Boston. The mission consists of a ground-based network of sensors already in operation as well as a space observatory, which uses a JPL-built camera that will be launched by the Italian Space Agency (ASI) on an ASI satellite no earlier than late 2027.

The camera is designed to identify different types of PM2.5 aerosols based on how they reflect light, making it possible to map particle concentrations over each city that the mission studies. Mounted on a gimbal, the camera captures data from multiple angles using JPL-pioneered technologies that make particles stand out more prominently against the surface background to provide valuable information about their shape and size.

The MAIA mission is the first NASA project to include public health researchers among a space mission’s team. These researchers will use MAIA’s PM2.5 concentration maps alongside health data to study potential relationships between different particle types and health outcomes. By developing a better understanding of particulate matter pollution, researchers can potentially advance how air quality is studied and managed.

“This paper shows how valuable the air sensor data is on its own, but combining the sensor network and satellite observations will be a game-changer,” said, Kyan Shlipak, the paper’s lead author, who worked on the research while interning at JPL.

Tracking black carbon

The greater Addis Ababa urban area is home to nearly 6 million people, and according to United Nations projections, that figure is expected to surpass 10 million by 2050.

“It’s a cosmopolitan city with many international communities,” said Araya Asfaw of Addis Ababa University, a coauthor of the paper and the MAIA project’s lead Ethiopian collaborator. “Think of it as Africa’s version of Brussels, where the European Union is based.”

“Even at night, when traffic dies down, you see high emissions from the burning of charcoal and other fuels,” Asfaw said.

The MAIA sensor network detected increases in black carbon during two major holidays in Addis Ababa that involve bonfires and was able to distinguish between particles originating from the fires and those from fossil fuel combustion. The findings demonstrate how detailed measurements can help researchers identify different sources of particulate matter and better understand how air quality varies across a city and over time.

To learn more about MAIA, visit:

https://science.nasa.gov/mission/maia/

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OIIR Nav

Aside from global access to cat videos, the presence of thousands of Starlink broadband internet access satellites in LEO has a very pleasant side effect for atmospheric researchers. Starlink publicly publishes near-real-time ephemeris data on its individual satellites. From this data you can deduce many details about the atmosphere at that altitude, including its density at specific altitudes at specific times, information which otherwise would be very hard to gather. Recently, this allowed [Mamoru Yamamoto] to determine the density of the thermosphere using tomography.

In a similar 2025 paper by [Zhuoliang Ou] et al. as published in Remote Sensing, this same data source was used to investigate details of the thermosphere. With Starlink publishing this data since 2021, this provides an invaluable dataset for studying this outermost part of the atmosphere.

Commencing just before the generally recognized transition into ‘space’ at 100 km altitude and below the Earth’s exosphere, the thermosphere‘s thickness fluctuates due to factors like solar irradiation and, with it, the exact altitude at which the exosphere begins. Generally, though, it is well above 600 km altitude. This places Starlink satellites as well as both active space stations (ISS and Tiangong) in the thermosphere.

[Zuholiang Ou] et al. established that the Starlink data matches well with that from a dedicated research satellite like SWARM-B, thus making it a useful source of scientific data.

The innovation in [Yamamoto-san]’s paper is that instead of using the typical two-line element (TLE) set, a more comprehensive tomographic approach was used, which essentially uses more data for a larger reconstruction, with the resolution claimed to be about on par with that of the SWARM satellites. This implies that although these Starlink satellites were never designed to be more than data relays, they may have accidentally become the biggest development in thermospheric research in a long time.

Of course, you can’t please everyone.