Preparations for Next Moonwalk Simulations Underway (and Underwater)
Artemis II crew members (left to right) Reid Wiseman, Christina Koch, and Jeremy Hansen share information about themselves and their mission during a town hall at NASA’s Glenn Research Center in Cleveland.
Credit:NASA/Sara Lowthian-Hanna
Three of the four astronauts who will venture around the Moon on Artemis II, the first crewed flight paving the way for future lunar surface missions, visited NASA’s Glenn Research Center in Cleveland, Sept. 10-11. NASA Glenn is an integral part of the development of the Orion spacecraft and a leader in propulsion, power, and communications research.
Commander Reid Wiseman and Mission Specialists Christina Koch and Jeremy Hansen (Canadian Space Agency) discussed their upcoming mission and hosted a question-and-answer session during town hall events at Lewis Field in Cleveland and NASA’s Neil Armstrong Test Facility in Sandusky, Ohio. Victor Glover, who was unable to attend, is the pilot and fourth crew member. Both events included tours and recognition of employees who have contributed to the success of Artemis missions.
Artemis II crew members Reid Wiseman, Christina Koch, and Jeremy Hansen (left to right, wearing blue flight suits) and other NASA personnel look down into the stainless-steel vacuum chamber in the In-Space Propulsion Facility at NASA’s Neil Armstrong Test Facility in Sandusky, Ohio. This is the world’s only facility capable of testing full-scale upper stage launch vehicles and rocket engines under simulated high-altitude conditions.
Credit:NASA/Sara Lowthian-Hanna
The Artemis II crew will lift off on an approximately 10-day mission from Launch Complex 39B at NASA’s Kennedy Space Center in Florida, blazing beyond Earth’s grasp atop the agency’s mega Moon rocket. The crew will check out Orion’s systems and perform a targeting demonstration test relatively close to Earth before venturing around the Moon.
NASA, NOAA: Sun Reaches Maximum Phase in 11-Year Solar Cycle
In a teleconference with reporters on Tuesday, representatives from NASA, the National Oceanic and Atmospheric Administration (NOAA), and the international Solar Cycle Prediction Panel announced that the Sun has reached its solar maximum period, which could continue for the next year.
The solar cycle is a natural cycle the Sun goes through as it transitions between low and high magnetic activity. Roughly every 11 years, at the height of the solar cycle, the Sun’s magnetic poles flip — on Earth, that’d be like the North and South poles swapping places every decade — and the Sun transitions from being calm to an active and stormy state.
Visible light images from NASA’s Solar Dynamics Observatory highlight the appearance of the Sun at solar minimum (left, Dec. 2019) versus solar maximum (right, May 2024). During solar minimum, the Sun is often spotless. Sunspots are associated with solar activity and are used to track solar cycle progress.
For these images and more relating to solar maximum, visit https://ift.tt/ncCAVM4.
NASA/SDO
Images from NASA’s Solar Dynamics Observatory highlight the appearance of the Sun at solar minimum (left, December 2019) versus solar maximum (right, May 2024). These images are in the 171-angstrom wavelength of extreme ultraviolet light, which reveals the active regions on the Sun that are more common during solar maximum.
For these images and more relating to solar maximum, visit https://ift.tt/ncCAVM4.
NASA/SDO
NASA and NOAA track sunspots to determine and predict the progress of the solar cycle — and ultimately, solar activity. Sunspots are cooler regions on the Sun caused by a concentration of magnetic field lines. Sunspots are the visible component of active regions, areas of intense and complex magnetic fields on the Sun that are the source of solar eruptions.
“During solar maximum, the number of sunspots, and therefore, the amount of solar activity, increases,” said Jamie Favors, director, Space Weather Program at NASA Headquarters in Washington. “This increase in activity provides an exciting opportunity to learn about our closest star — but also causes real effects at Earth and throughout our solar system.”
The solar cycle is the natural cycle of the Sun as it transitions between low and high activity. During the most active part of the cycle, known as solar maximum, the Sun can unleash immense explosions of light, energy, and solar radiation — all of which create conditions known as space weather. Space weather can affect satellites and astronauts in space, as well as communications systems — such as radio and GPS — and power grids on Earth.
Credits: Beth Anthony/NASA
Solar activity strongly influences conditions in space known as space weather. This can affect satellites and astronauts in space, as well as communications and navigation systems — such as radio and GPS — and power grids on Earth. When the Sun is most active, space weather events become more frequent. Solar activity has led to increased aurora visibility and impacts on satellites and infrastructure in recent months.
During May 2024, a barrage of large solar flares and coronal mass ejections (CMEs) launched clouds of charged particles and magnetic fields toward Earth, creating the strongest geomagnetic storm at Earth in two decades — and possibly among the strongest displays of auroras on record in the past 500 years.
May 3–May 9, 2024, NASA’s Solar Dynamics Observatory observed 82 notable solar flares. The flares came mainly from two active regions on the Sun called AR 13663 and AR 13664. This video highlights all flares classified at M5 or higher with nine categorized as X-class solar flares. Credit: NASA
“This announcement doesn’t mean that this is the peak of solar activity we’ll see this solar cycle,” said Elsayed Talaat, director of space weather operations at NOAA. “While the Sun has reached the solar maximum period, the month that solar activity peaks on the Sun will not be identified for months or years.”
Scientists will not be able to determine the exact peak of this solar maximum period for many months because it’s only identifiable after they’ve tracked a consistent decline in solar activity after that peak. However, scientists have identified that the last two years on the Sun have been part of this active phase of the solar cycle, due to the consistently high number of sunspots during this period. Scientists anticipate that the maximum phase will last another year or so before the Sun enters the declining phase, which leads back to solar minimum. Since 1989, the Solar Cycle Prediction Panel — an international panel of experts sponsored by NASA and NOAA — has worked together to make their prediction for the next solar cycle.
Solar cycles have been tracked by astronomers since Galileo first observed sunspots in the 1600s. Each solar cycle is different — some cycles peak for larger and shorter amounts of time, and others have smaller peaks that last longer.
Sunspot number over the previous 24 solar cycles. Scientists use sunspots to track solar cycle progress; the dark spots are associated with solar activity, often as the origins for giant explosions — such as solar flares or coronal mass ejections — which can spew light, energy, and solar material out into space.
For these images and more relating to solar maximum, visit https://ift.tt/ncCAVM4.
NOAA’s Space Weather Prediction Center
“Solar Cycle 25 sunspot activity has slightly exceeded expectations,” said Lisa Upton, co-chair of the Solar Cycle Prediction Panel and lead scientist at Southwest Research Institute in San Antonio, Texas. “However, despite seeing a few large storms, they aren’t larger than what we might expect during the maximum phase of the cycle.”
The most powerful flare of the solar cycle so far was an X9.0 on Oct. 3 (X-class denotes the most intense flares, while the number provides more information about its strength).
NOAA anticipates additional solar and geomagnetic storms during the current solar maximum period, leading to opportunities to spot auroras over the next several months, as well as potential technology impacts. Additionally, though less frequent, scientists often see fairly significant storms during the declining phase of the solar cycle.
The Solar Cycle 25 forecast, as produced by the Solar Cycle 25 Prediction Panel. Sunspot number is an indicator of solar cycle strength — the higher the sunspot number, the stronger the cycle.
For these images and more relating to solar maximum, visit https://ift.tt/ncCAVM4.
NOAA’s Space Weather Prediction Center
NASA and NOAA are preparing for the future of space weather research and prediction. In December 2024, NASA’s Parker Solar Probe mission will make its closest-ever approach to the Sun, beating its own record of closest human-made object to the Sun. This will be the first of three planned approaches for Parker at this distance, helping researchers to understand space weather right at the source.
NASA is launching several missions over the next year that will help us better understand space weather and its impacts across the solar system.
Space weather predictions are critical for supporting the spacecraft and astronauts of NASA’s Artemis campaign. Surveying this space environment is a vital part of understanding and mitigating astronaut exposure to space radiation.
NASA works as a research arm of the nation’s space weather effort. To see how space weather can affect Earth, please visit NOAA’s Space Weather Prediction Center, the U.S. government’s official source for space weather forecasts, watches, warnings, and alerts.
By Abbey Interrante NASA’s Goddard Space Flight Center, Greenbelt, Md.
Media Contact: Sarah Frazier, NASA’s Goddard Space Flight Center, Greenbelt, Md. sarah.frazier@nasa.gov
Making the most of a solar eclipse demands attention to detail. Do you have what it takes? NASA’s Eclipse Megamovie project launched a new coding competition, and they need your help to organize images from the April 8, 2024 total solar eclipse. This is your chance to make a lasting contribution to solar science!
The Eclipse Megamovie project asked volunteers to take photos of the total solar eclipse that took place on April 8, 2024 to discover the secret lives of solar jets and plumes. Many jets and plumes seem to disappear or change from the time they are formed on the Sun to when they move out into the solar wind. Thanks to the efforts of over 145 citizen scientists, more than 1 terabyte of photographs were collected and are now being analyzed. These images will help scientists track disappearing jets and plumes, shedding light on how these solar events impact space weather and our understanding of the Sun’s outer atmosphere.
One of the standout volunteers in the Eclipse Megamovie project is Hy Tran, a citizen scientist who earned praise from the science team for his detailed feedback and mentorship of fellow volunteers. “We love working with volunteers like Hy,” said Eclipse Megamovie scientist Hannah Hellman. “They bring passion, experience, and technological knowledge to our projects.”
Superstar volunteer Hy Tran helps mentor other eclipse chasers. You can join the Eclipse Megamovie project now by taking part in a coding competition!
Tran’s day job is in metrology—the science of measurement (not to be confused with meteorology!). “In my professional life,” said Tran, “I support a measurement standards and calibration program, so we live by having good procedures!” He also volunteers in technical societies, focusing on standards development, engineering, and technology education. Outside of work, Hy mentors and serves as a local leader in science/technology/engineering/mathematics (STEM) outreach. He loves woodturning and dabbles in amateur astrophotography and underwater photography. The technical challenges of participating in eclipse science projects so far have hit his sweet spot.
Although it will be a while until the next eclipse, the Eclipse Megamovie team still needs your help. Join volunteers like Hy and participate in their coding competition! Your mission is to create the most accurate sorting machine that categorizes a solar eclipse photograph into a specific solar eclipse phase. Not only will your code help organize the massive amounts of data collected, but you’ll also have the chance to win some prizes.
Prizes for the Competition
First Place: Image-stabilized binoculars with solar filters, a feature on the Eclipse Megamovie website, an Eclipse Megamovie Team Patch, a NASA calendar, an Eclipse Megamovie sticker, and a First Prize Certificate.
Second and Third Place: A feature on the Eclipse Megamovie website, an Eclipse Megamovie Team Patch, a NASA calendar, an Eclipse Megamovie sticker, and a certificate.
Think you’ve got the skills to tackle this challenge? Visit the Eclipse Megamovie project website to sign up today!
For more information, visit the Eclipse Megamovie page at Kaggle: https://ift.tt/6cML2BN.
The study of X-ray emission from astronomical objects reveals secrets about the Universe at the largest and smallest spatial scales. Celestial X-rays are produced by black holes consuming nearby stars, emitted by the million-degree gas that traces the structure between galaxies, and can be used to predict whether stars may be able to host planets hospitable to life. X-ray observations have shown that most of the visible matter in the universe exists as hot gas between galaxies and have conclusively demonstrated that the presence of “dark matter” is needed to explain galaxy cluster dynamics, that dark matter dominates the mass of galaxy clusters, and that it governs the expansion of the cosmos.
X-ray observations also enable us to probe mysteries of the Universe on the smallest scales. X-ray observations of compact objects such as white dwarfs, neutron stars, and black holes allow us to use the Universe as a physics laboratory to study conditions that are orders of magnitude more extreme in terms of density, pressure, temperature, and magnetic field strength than anything that can be produced on Earth. In this astrophysical laboratory, researchers expect to reveal new physics at the subatomic scale by conducting investigations such as probing the neutron star equation of state and testing quantum electrodynamics with observations of neutron star atmospheres. At NASA’s Marshall Space Flight Center, a team of scientists and engineers is building, testing, and flying innovative optics that bring the Universe’s X-ray mysteries into sharper focus.
A composite X-ray/Optical/Infrared image of the Crab Pulsar. The X-ray image from the Chandra X-ray Observatory (blue and white), reveals exquisite details in the central ring structures and gas flowing out of the polar jets. Optical light from the Hubble Space Telescope (purple) shows foreground and background stars as pinpoints of light. Infrared light from the Spitzer Space Telescope (pink) traces cooler gas in the nebula. Finally, magnetic field direction derived from X-ray polarization observed by the Imaging X-ray Polarimetry Explorer is shown as orange lines.
Magnetic field lines: NASA/Bucciantini et al; X-ray: NASA/CXC/SAO; Optical: NASA/STScI; Infrared: NASA-JPL-Caltech
Unlike optical telescopes that create images by reflecting or refracting light at near-90-degree angles (normal incidence), focusing X-ray optics must be designed to reflect light at very small angles (grazing incidence). At normal incidence, X-rays are either absorbed by the surface of a mirror or penetrate it entirely. However, at grazing angles of incidence, X-rays reflect very efficiently due to an effect called total external reflection. In grazing incidence, X-rays reflect off the surface of a mirror like rocks skipping on the surface of a pond.
A classic design for astronomical grazing incidence optics is the Wolter-I prescription, which consists of two reflecting surfaces, a parabola and hyperbola (see figure below). This optical prescription is revolved around the optical axis to produce a full-shell mirror (i.e., the mirror spans the full circumference) that resembles a gently tapered cone. To increase the light collecting area, multiple mirror shells with incrementally larger diameters and a common focus are fabricated and nested concentrically to comprise a mirror module assembly (MMA).
Focusing optics are critical to studying the X-ray universe because, in contrast to other optical systems like collimators or coded masks, they produce high signal-to-noise images with low background noise. Two key metrics that characterize the performance of X-ray optics are angular resolution, which is the ability of an optical system to discriminate between closely spaced objects, and effective area, which is the light collecting area of the telescope, typically quoted in units of cm2. Angular resolution is typically measured as the half-power diameter (HPD) of a focused spot in units of arcseconds. The HPD encircles half of the incident photons in a focused spot and measures the sharpness of the final image; a smaller number is better.
Schematic of a full-shell Wolter-I X-ray optic mirror module assembly with five concentrically nested mirror shells. Parallel rays of light enter from the left, reflect twice off the reflective inside surface of the shell (first off the parabolic segment and then off the hyperbolic segment), and converge at the focal plane.
NASA MSFC
NASA Marshall Space Flight Center (MSFC) has been building and flying lightweight, full-shell, focusing X-ray optics for over three decades, always meeting or exceeding angular resolution and effective area requirements. MSFC utilizes an electroformed nickel replication (ENR) technique to make these thin full-shell X-ray optics from nickel alloy.
X-ray optics development at MSFC began in the early 1990s with the fabrication of optics to support NASA’s Advanced X-ray Astrophysics Facility (AXAF-S) and then continued via the Constellation-X technology development programs. In 2001, MSFC launched a balloon payload that included two modules each with three mirrors, which produced the first focused hard X-ray (>10 keV) images of an astrophysical source by imaging Cygnus X-1, GRS 1915, and the Crab Nebula. This initial effort resulted in several follow-up missions over the next 12 years, and became known as the High Energy Replicated Optics (HERO) balloon program.
In 2012, the first of four sounding rocket flights of the Focusing Optics X-ray Solar Imager (FOXSI) flew with MSFC optics onboard, producing the first focused images of the Sun at energies greater than 5 keV. In 2019 the Astronomical Roentgen Telescope X-ray Concentrator (ART-XC) instrument on the Spectr-Roentgen-Gamma Mission launched with seven MSFC-fabricated X-ray MMAs, each containing 28 mirror shells. ART-XC is currently mapping the sky in the 4-30 keV hard X-ray energy range, studying exotic objects like neutron stars in our own galaxy as well as active galactic nuclei, which are spread across the visible universe. In 2021, the Imaging X-ray Polarimetry Explorer (IXPE), flew and is now performing extraordinary science with an MSFC-led team using three, 24-shell MMAs that were fabricated and calibrated in-house.
Most recently, in 2024, the fourth FOXSI sounding rocket campaign launched with a high-resolution MSFC MMA. The optics achieved 9.5 arcsecond HPD angular resolution during pre-flight test with an expected 7 arcsecond HPD in gravity-free flight, making this the highest angular resolution flight observation made with a nickel-replicated X-ray optic. Currently MSFC is fabricating an MMA for the Rocket Experiment Demonstration of a Soft X-ray (REDSoX) polarimeter, a sounding rocket mission that will fly a novel soft X-ray polarimeter instrument to observe active galactic nuclei. The REDSoX MMA optic will be 444 mm in diameter, which will make it the largest MMA ever produced by MSFC and the second largest replicated nickel X-ray optic in the world.
Scientists Wayne Baumgartner (left, crouched) and Nick Thomas (left, standing) calibrate an IXPE MMA in the MSFC 100 m Beamline. Scientist Stephen Bongiorno (right) applies epoxy to an IXPE shell during MMA assembly.
NASA MSFC
The ultimate performance of an X-ray optic is determined by errors in the shape, position, and roughness of the optical surface. To push the performance of X-ray optics toward even higher angular resolution and achieve more ambitious science goals, MSFC is currently engaged in a fundamental research and development effort to improve all aspects of full-shell optics fabrication.
Given that these optics are made with the Electroformed Nickel Replication technique, the fabrication process begins with creation of a replication master, called the mandrel, which is a negative of the desired optical surface. First, the mandrel is figured and polished to specification, then a thin layer of nickel alloy is electroformed onto the mandrel surface. Next, the nickel alloy layer is removed to produce a replicated optical shell, and finally the thin shell is attached to a stiff holding structure for use.
Each step in this process imparts some degree of error into the final replicated shell. Research and development efforts at MSFC are currently concentrating on reducing distortion induced during the electroforming metal deposition and release steps. Electroforming-induced distortion is caused by material stress built into the electroformed material as it deposits onto the mandrel. Decreasing release-induced distortion is a matter of reducing adhesion strength between the shell and mandrel, increasing strength of the shell material to prevent yielding, and reducing point defects in the release layer.
Additionally, verifying the performance of these advanced optics requires world-class test facilities. The basic premise of testing an optic designed for X-ray astrophysics is to place a small, bright X-ray source far away from the optic. If the angular size of the source, as viewed from the optic, is smaller than the angular resolution of the optic, the source is effectively simulating X-ray starlight. Due to the absorption of X-rays by air, the entire test facility light path must be placed inside a vacuum chamber.
At MSFC, a group of scientists and engineers operate the Marshall 100-meter X-ray beamline, a world-class end-to-end test facility for flight and laboratory X-ray optics, instruments, and telescopes. As per the name, it consists of a 100-meter-long vacuum tube with an 8-meter-long, 3-meter-diameter instrument chamber and a variety of X-ray sources ranging from 0.25 – 114 keV. Across the street sits the X-Ray and Cryogenic Facility (XRCF), a 527-meter-long beamline with an 18-meter-long, 6-meter-diameter instrument chamber. These facilities are available for the scientific community to use and highlight the comprehensive optics development and test capability that Marshall is known for.
Within the X-ray astrophysics community there exist a variety of angular resolution and effective area needs for focusing optics. Given its storied history in X-ray optics, MSFC is uniquely poised to fulfill requirements for large or small, medium- or high-angular-resolution X-ray optics. To help guide technology development, the astrophysics community convenes once per decade to produce a decadal survey. The need for high-angular-resolution and high-throughput X-ray optics is strongly endorsed by the National Academies of Sciences, Engineering, and Medicine report, Pathways to Discovery in Astronomy and Astrophysics for the 2020s.In pursuit of this goal, MSFC is continuing to advance the state of the art in full-shell optics. This work will enable the extraordinary mysteries of the X-ray universe to be revealed.
Project Leads
Dr. Jessica Gaskin and Dr. Stephen Bongiorno, NASA Marshall Space Flight Center (MSFC)
Sponsoring Organizations
The NASA Astrophysics Division supports this work primarily through the Internal Scientist Funding Model Direct Work Package and competed solicitations. This work is also supported by the Heliophysics Division through competed solicitations, as well as by directed work from other government entities.
Preparations for Next Moonwalk Simulations Underway (and Underwater)
At the end of 2022, 65 percent of the Western United States was in severe drought, the result of a two decades long mega drought in the Colorado River Basin that had captured headlines around the world.
However, it was flooding, not drought, that was making headlines when we began our research for this story about OpenET, a revolutionary new online platform geared towards helping farmers and water managers monitor and reduce water use in watersheds where supplies were not keeping up with demand.
The start of 2023 brought flooding to many counties in California, leaving 68 percent of the state with suddenly little to no drought. And caused Forrest Melton, the NASA Project Scientist for OpenET and Associate Program Manager for agriculture and water resources with the NASA Earth Action program, to pause our video interview after a tree fell down outside his Bay Area home on a rainy day in March, 2023.
Coming online again after calling the fire department, Melton didn’t seem all too optimistic that the wet conditions would last. “California tends to swing between the two extremes of drought and flood,” Melton said. He referenced the 2016/17 winter which had particularly high precipitation but was followed by dry conditions during the following years, before the relief brought by the heavy rains, and flooding, in early 2023.
According to NOAA’s National Integrated Drought Information System it will take more than one wet winter to replenish groundwater in many parts of the western United States. Groundwater levels across the California Central Valley and many parts of the Ogallala Aquifer continue to decline. The need for better water management remains essential, and yet the data necessary to support new approaches has not been broadly available.
Enter the OpenET project, a multi-disciplinary, collaborative effort to make satellite-based evapotranspiration (ET) data available to the public. Melton describes the project as providing invaluable and scientifically robust data at all scales, “that can be used to support day to day decision making and long range planning to try to solve some really long standing and important water management challenges in the West.”
What is Evapotranspiration?
Evapotranspiration is the combined process of evaporation and transpiration, both of which transfer water from the land surface to the atmosphere as water vapor. Evaporation transforms water from the surface of the ground or bodies of water into water vapor, while transpiration is water vapor that is evaporated from plant tissues and escapes through the stomata, the tiny pores in plant leaves and stems. It is a process that is happening all around us almost all the time, but because water vapor is invisible to the human eye, it is very hard to measure on the ground.
A conceptual diagram of near-surface hydrology.
M. W. Toews
To understand the effect evapotranspiration has on a local water cycle, picture a large decorative fountain. Typically, these fountains recycle the same water over and over. As a fountain runs, water is pumped out of the fountain heads, falls back into the fountain’s basin, and then flows back through the pipe system before starting the process all over again. We can think of the water remaining within this fountain’s local water system as non-consumptive water use. Some water, however, will be lost from the fountain’s local water system by evaporating from the pool’s surface or mist from the fountain’s spray.
Imagine the fountain also has lily pads growing in its basin. The lily pads will use the fountain’s water to survive and grow, losing some of that water to transpiration. The total water lost is evapotranspiration, and is considered consumptive water use, because it cannot be reused by the fountain. Tracking evapotranspiration can tell you how much water is removed or “depleted” from a local water system, and how much water needs to be added back in to support plant growth and maintain a healthy balance between water supply and water use. If too much water leaves the fountain, it will stop running. If too much water is added, it will overflow.
These concepts can be applied more broadly to the hydrologic cycle as a whole, and evapotranspiration data can play an important part in designing and implementing sustainable water management practices to combat larger issues like drought, as well as both short and long-term reductions in water availability. Historically, ET data have been obtained from ground-based instruments and methods, such as weighing lysimeters, which weigh soil and plants to track the water volume lost by evaporation or transpiration. Another common method is called eddy covariance, which calculates the amount of water vapor transported away from the land surface by wind eddies as they move across the land surface. But both are expensive and difficult to install and maintain, and measurements are only representative of a small portion of an individual agricultural field. It is cost prohibitive to collect these measurements over larger areas.
What makes OpenET different?
The OpenET team saw the important niche left open by traditional evapotranspiration measurement methods and filled it. They built upon decades of research funded by NASA, USDA and USGS and developed a new platform that can take easily accessible and already available data from satellite programs, like Landsat, and combine it with weather data to calculate the ET for every quarter acre of land. Satellites can record information like the Earth’s surface temperature and how much of the incoming light from the sun is being reflected back out to space. OpenET is able to use physically-based mathematical models to combine the satellite and weather data and output accurate data on evapotranspiration rates and volumes.
This information is then made easily accessible through OpenET’s Data Explorer, a free web-based tool that allows anyone with an internet connection to access the data OpenET provides. Users begin by selecting an area of interest from a map of the western United States that provides data at the satellite resolution of a quarter-acre, and also broken down into known areas of interest and individual agricultural fields, each color coded with a heat map of evapotranspiration. Cooler colors indicate higher rates of evapotranspiration while warmer colors indicate lower rates. Users can zoom into specific areas on the map, and with just a click, a chart pops up showing the evapotranspiration trends for a given area, for the current year and the past five years.
The chart can show monthly ET trends, useful for understanding seasonal fluctuations, and also cumulative trends, useful for understanding year-to-year changes in evapotranspiration. “The OpenET team took a user-driven design approach from the beginning, and each element of the Data Explorer and the open data services is there because a water manager or farmer asked for it,” Melton explained. As we played around with the map, it became apparent how much work was put into developing this project. Scientists needed to improve models and assess the accuracy of data, programmers had to develop the user interface and data services, designers needed to make the interface intuitive enough to be impactful, agriculture and environmental groups needed to help validate the model’s accuracy, and users of all types needed to provide requirements and then test the product to make sure their needs were actually met.
The OpenET consortium includes NASA, USGS, USDA Agricultural Research Service (ARS), Environmental Defense Fund (EDF), Google Earth Engine, California State University Monterey Bay (CSUMB), Desert Research Institute (DRI), Habitat Seven, Chapman University, Cornell University, University of Nebraska-Lincoln and close to a dozen other universities and experts across the U.S. NASA Ames Research Center and CSUMB have played key roles in the scientific and technical leadership of the effort from the outset, working closely with DRI, EDF and the recently formed non-profit OpenET, Inc. In addition, over 100 partners from the water management, agriculture and conservation community provided user requirements and assisted with the design and testing of the OpenET platform and tools.
“OpenET would not be possible without the contributions of each one of those partners,” Melton said. “Both on the implementation side and those who are translating the data from OpenET into solutions to long standing challenges.”
Map of farmlands showing ET data for 2024. The cooler colors represent higher levels of evapotranspiration (ET), while warmer colors indicate areas with less ET.
OpenET
Models like those built into OpenET can be extremely useful tools for understanding patterns in ET and water use, but are only helpful if their accuracy is known. The OpenET science team recently completed the largest accuracy assessment to date for field-scale satellite-based ET data, comparing the satellite data to ground-based measurements at more than 150 sites across the U.S. Led by John Volk of the Desert Research Institute, the study was published in Nature Water earlier this year. A key finding was that across all sites, an ensemble value computed from six different ET models performed the best overall, leveraging the strengths of each individual satellite-driven model.
However, the study also found that some models performed best for particular crop types or regions, which is important information for water managers and farmers who need the most accurate data possible. Publishing the results as an open access study with all data and analysis made publicly available was also important to build trust in the data. While the study highlighted some limitations of the models and priorities for future research, the rigorous and reproducible accuracy assessment helps to build user confidence that they can use the data, while being aware of the expected accuracy for different applications of the data.
Bridging the Gap Between Farmers and Resource Managers
OpenET has already contributed to one significant win for farmers that affects how water use will be monitored and reported in the Sacramento-San Joaquin Delta.
This inland river delta covers 750,000 acres and is an important water resource in California, but one where accelerated demand combined with habitat loss and water quality issues has led to major concerns. In the Delta, large portions of the agricultural land are below sea level. Levees protect the fields and contain the river channels that supply water for irrigation. In 2023, the state began requiring farmers to maintain a water meter or measuring device on each diversion, where water is diverted from a river for irrigation. However, this measurement proved challenging and costly as there are thousands of diversions in the Delta, and the measuring equipment was inaccurate and difficult to maintain in this environment. In addition, water users also had to pay for meters at the locations where water that drained from the fields was pumped back over the levees and into the river channels.
The Sacramento-San Joaquin River Delta is a major water resource in California.
Matthew Trump
“Mostly, what the state was interested in was the consumptive use: how much (water) was actually removed from the supply in that region,” Melton said. “So, it’s the perfect place for using OpenET because evapotranspiration really is the majority of the consumptive use in the Delta, if not all of it.”
After the launch of OpenET, farmers in the Delta worked with the Delta Watermaster, the California State Water Resources Control Board, the OpenET team and the Delta Measurement Consortium to develop an alternative compliance plan that used OpenET data to help streamline the water use required reporting for this complex region. Once the alternative compliance plan was approved, Forrest Melton and Will Carrara of NASA worked with the state Water Resources Control Board, the Delta Watermaster and water management agencies, and Jordan Harding of HabitatSeven to implement this solution. The Delta Alternative Compliance Plan, also known as the Delta ACP, allows farmers to use OpenET data to estimate their water usage; enabling farmers to complete their use reports in a matter of minutes.
“It’s the first time that satellite-based evapotranspiration data has been automatically integrated with a state-managed water reporting system,” Melton said.
Last year, more than 70% of farmers in the Bay-Delta region chose to use OpenET and to report their water use through the Delta ACP website, and they expect this percentage to continue to increase over time.
“The best part is that it is saving farmers hundreds of hours on preparing and submitting reports, avoiding millions of dollars in costs for farmers to deploy and maintain meters, and giving the state consistent and reproducible data on water use that has been reviewed and approved by the water user,” Melton said.
According to Delta Watermaster, Jay Ziegler, this approach has a clear benefit in the unique water flow setting of the Delta. “In reality, OpenET – and the use of publicly accessible data measuring ET is the only way to really discern consumptive use of water in the Delta on a reliable basis,” Ziegler said. “Candidly, we don’t really have a viable “plan B” in the absence of applying Open ET for water use reporting.”
In reality, OpenET – and the use of publicly accessible data measuring ET is the only way to really discern consumptive use of water in the Delta on a reliable basis.
Jay ziegler
Sacramento-San Joaquin Delta Watermaster
Water Beyond Borders
As water scarcity is increasingly becoming an urgent issue all around the world, it’s easy to imagine how many countries could benefit from OpenET data.
OpenET’s first international partnership is led by Anderson Ruhoff, a professor in Hydrology and Remote Sensing at the Federal University of Rio Grande do Sul, Brazil, where his team developed an evapotranspiration model called geeSEBAL for Brazil’s Water Agency.
Ruhoff learned about OpenET while he was in the US on a visiting professorship in Nebraska. He was intrigued and reached out to Melton who encouraged him to attend an upcoming conference in Reno, Nevada, where OpenET would be featured. The conference was due to start in just a few days time.
“So I had to find a last minute ticket to Reno and I’m glad I bought it, because when I arrived there they invited me to join Open ET. It was quite a coincidence,” Ruhoff said, smiling as he remembered the spontaneous decision. “We adapted our model for the US and started to participate in their work.”
In March, 2024, Ruhoff and OpenET launched an extension of the tool, called OpenET Brazil, with financial support from the Agência Nacional de Águas e Saneamento Básico (ANA), the Brazilian national water agency. The tool, called OpenET Brazil, will have similar goals as OpenET in the U.S., and the data collected will help improve Open ET’s accuracy overall.
Melton feels this will be a “great test case” for both working with new environmental conditions (in Brazil there frequently is more cloud cover than in the US during key parts of the growing season) and also developing new collaborations.
“The partnership will help us figure out how we can work with international partners to make the ET data useful,” Melton said. “The key aspect of our approach to geographic expansion is that leading scientists in each country and region, like Dr. Ruhoff, will lead the implementation, accuracy assessment, and the development of applications and partnerships for their country.”
Brazil has one of the world’s largest sources of freshwater, the Amazon River, and yet it can still be affected by drought. This is partly due to the fact that deforestation in the Amazon Rainforest has an impact on the entire region’s water cycle. Trees draw water up from the soil and during photosynthesis they release vapor into the atmosphere. This water vapor will accumulate and form precipitation. Trees are “basically a huge water pump,” Ruhoff said, and the Amazon Rainforest is large enough that it helps to produce the rainy season. But when deforestation is allowed to happen over large areas, that mechanism is interrupted. As a result of this disruption, the dry season is predicted to intensify, becoming longer and dryer, which in turn can affect crop production in Brazil as well as the rainfall that is critical for sustaining water supplies in Brazil and other areas of South America.
“Water doesn’t see borders. It doesn’t follow our rules,” Ruhoff said. “Deforestation in one place can affect people thousands of kilometers away.”
Water doesn’t see borders. It doesn’t follow our rules. Deforestation in one place can affect people thousands of kilometers away.
Anderson Ruhoff
Professor of Hydrology and Remote Sensing, Federal University of Rio Grande do Sul, Brazil
Studying evapotranspiration can reveal the impacts of deforestation with even more clarity. And importantly, it’s also public information. “So not only the farmers and water managers but every citizen can check how much water is being used in their area, especially during drought. It’s democratic information in that way,” Ruhoff said. “I think it’s important to have this information openly available and to try and reach as many people as possible.”
Melton feels there’s the potential to expand the project, if more people like Ruhoff are there to lead the way.
“There’s huge potential, but there do need to be stakeholders that come to the table and say that this is something that they’re interested in,” Melton said. “Water is so important and at times so contentious that it’s really important the data is seen as trusted. When there is a local leader, that substantially increases the likelihood that it will be trusted, and most importantly, used to bring people together to develop solutions.”
The geeSEBAL application that Anderson Ruhoff’s team developed, which now informs the OpenET platform.
Science Direct/Anderson Ruhoff
Even when you live in a water-scarce region like California it’s easy to take water for granted. What platforms like OpenET can do for us, however, is make water, even in its most diffuse form, more visible to everyone.
Written by Jane Berg and Rachel Sender, co-published with the Bay Area Environmental Research Institute
