Members Can Post Anonymously On This Site
-
Similar Topics
-
By NASA
Teams at NASA’s Kennedy Space Center in Florida participate in the first joint integrated launch countdown simulation for Artemis I inside Firing Room 1 of the Launch Control Center on July 8, 2021. Seen at the top of the room is Charlie Blackwell-Thompson (right), launch director.Credit: NASA/Ben Smegelsky As four astronauts venture around the Moon on NASA’s Artemis II test flight in 2026, many people will support the journey from here on Earth. Teams directing operations from the ground include the mission management team, launch control team, flight control team, and the landing and recovery team, each with additional support personnel who are experts in every individual system and subsystem. The teams have managed every aspect of the test flight and ensure NASA is prepared to send humans beyond our atmosphere and into a new Golden Age of innovation and exploration.
Mission management team
Reviews of mission status and risk assessments are conducted by the mission management team, a group of 15 core members and additional advisors. Amit Kshatriya, NASA’s deputy associate administrator, Moon to Mars Program, will serve as the mission management team chair for the test flight.
Two days prior to launch, the mission management team will assemble to review mission risks and address any lingering preflight concerns. With more than 20 years of human spaceflight experience, Kshatriya will conduct polls at key decision points, providing direction for the relevant operations team. If circumstances during the flight go beyond established decision criteria or flight rules outlined ahead of the mission, the team will assess the situation based on the information available and decide how to respond.
Matt Ramsey, serving as the Artemis II mission manager, will oversee all elements of mission preparedness prior to the mission management team assembly two days before launch and serve as deputy mission management team chair throughout the mission. With more than two decades of experience at NASA, Ramsey managed the SLS (Space Launch System) Engineering Support Center for Artemis I.
Launch control team
The launch control team coordinates launch operations from NASA’s Kennedy Space Center in Florida. Charlie Blackwell-Thompson serves as the agency’s Artemis launch director, responsible for integrating and coordinating launch operations for the SLS, Orion, and Exploration Ground Systems Programs, including developing and implementing plans for countdown, troubleshooting, and timing.
Two days before liftoff, when the countdown for launch begins, Blackwell-Thompson’s team will begin preparations for launch from their console positions in Firing Room 1 in Kennedy’s Launch Control Center. On the day of launch, Blackwell-Thompson and her team will manage countdown progress, propellent loading, and launch commit criteria. The criteria include standards for systems involved in launch, and the team will monitor the rocket until it lifts off from the launchpad.
Rick Henfling, flight director, monitors systems in the Flight Control Center at NASA’s Johnson Space Center in Houston.Credit: NASA Flight control team
From solid rocket booster ignition until the crew is safety extracted from the Orion capsule following splashdown in the Pacific Ocean at the end of their mission, the flight control team oversees operations from the Mission Control Center at NASA’s Johnson Space Center in Houston. Multiple flight directors will take turns leading the team throughout the 10-day mission to support operations around the clock. Jeff Radigan, bringing more than 20 years of International Space Station experience to Artemis II, will serve as lead flight director for the mission. The work for this role begins well in advance of the mission with building mission timelines; developing flight rules and procedures; leading the flight control team through simulations that prepare them for the flight test; and then helping them carry out the plan.
On launch day, the ascent flight control team will be led by Judd Frieling, an Artemis I flight director who also supported more than 20 shuttle missions as a flight controller. Frieling is responsible for overseeing the crew’s ascent to space, including performance of SLS core stage engines, solid rocket boosters, and propulsion systems from the moment of launch until the separation of Orion from the Interim Cryogenic Propulsion Stage. As Orion is propelled toward the Moon, guidance of operations will pass to the next flight director.
At the opposite end of the mission, Rick Henfling will take the lead for Orion’s return to Earth and splashdown. Orion will reenter Earth’s atmosphere at roughly 25,000 mph to about 20 mph for a parachute-assisted splashdown. Drawing from a background supporting space shuttle ascent, entry, and abort operations and 10 years as a space station flight director, Henfling and the team will monitor weather forecasts for landing, watch over Orion’s systems through the dynamic entry phase, and to ensure the spacecraft is safely shutdown before handing over operations to the recovery team.
At any point during the mission, a single voice will speak to the crew in space on behalf of all members of the flight control team: the capsule communicator, or CapCom. The CapCom ensures the crew in space receives clear and concise communication from the teams supporting them on the ground. NASA astronaut Stan Love will serve as the lead CapCom for Artemis II. Love flew aboard STS-122 mission and has acted as CapCom for more than a dozen space station expeditions. He is also part of the astronaut office’s Rapid Prototyping Lab, which played a key role in development of Orion’s displays and controls.
Landing, recovery team
Retrieval of the crew and Orion crew module will be in the hands of the landing and recovery team, led by Lili Villarreal. The team will depart San Diego on a Department of Defense ship, and head to the vicinity of the landing site several days before splashdown for final preparations alongside the U.S. Navy and DOD.
The recovery team is made up of personnel operating from the ship, land, and air to recover both astronauts and the capsule. Decision-making authority during the recovery phase of mission operations belongs to Villarreal, who served as deputy flow director for Artemis I and worked in the operations division for the space station.
The success of Artemis II will pave the way for the next phase of the agency’s campaign, landing on the lunar South Pole region on Artemis III. These teams, along with the four crew members and countless NASA engineers, scientists, and personnel, are driving humanity’s exploration on the Moon, Mars, and beyond.
View the full article
-
By NASA
5 min read
Astronomers Map Stellar ‘Polka Dots’ Using NASA’s TESS, Kepler
Scientists have devised a new method for mapping the spottiness of distant stars by using observations from NASA missions of orbiting planets crossing their stars’ faces. The model builds on a technique researchers have used for decades to study star spots.
By improving astronomers’ understanding of spotty stars, the new model — called StarryStarryProcess — can help discover more about planetary atmospheres and potential habitability using data from telescopes like NASA’s upcoming Pandora mission.
“Many of the models researchers use to analyze data from exoplanets, or worlds beyond our solar system, assume that stars are uniformly bright disks,” said Sabina Sagynbayeva, a graduate student at Stony Brook University in New York. “But we know just by looking at our own Sun that stars are more complicated than that. Modeling complexity can be difficult, but our approach gives astronomers an idea of how many spots a star might have, where they are located, and how bright or dark they are.”
A paper describing StarryStarryProcess, led by Sagynbayeva, published Monday, August 25, in The Astrophysical Journal.
Watch to learn how a new tool uses data from exoplanets, worlds beyond our solar system, to tell us about their polka-dotted stars.
NASA’s Goddard Space Flight Center
Download images and videos through NASA’s Scientific Visualization Studio.
NASA’s TESS (Transiting Exoplanet Survey Satellite) and now-retired Kepler Space Telescope were designed to identify planets using transits, dips in stellar brightness caused when a planet passes in front of its star.
These measurements reveal how the star’s light varies with time during each transit, and astronomers can arrange them in a plot astronomers call a light curve. Typically, a transit light curve traces a smooth sweep down as the planet starts passing in front of the star’s face. It reaches a minimum brightness when the world is fully in front of the star and then rises smoothly as the planet exits and the transit ends.
By measuring the time between transits, scientists can determine how far the planet lies from its star and estimate its surface temperature. The amount of missing light from the star during a transit can reveal the planet’s size, which can hint at its composition.
Every now and then, though, a planet’s light curve appears more complicated, with smaller dips and peaks added to the main arc. Scientists think these represent dark surface features akin to sunspots seen on our own Sun — star spots.
The Sun’s total number of sunspots varies as it goes through its 11-year solar cycle. Scientists use them to determine and predict the progress of that cycle as well as outbreaks of solar activity that could affect us here on Earth.
Similarly, star spots are cool, dark, temporary patches on a stellar surface whose sizes and numbers change over time. Their variability impacts what astronomers can learn about transiting planets.
Scientists have previously analyzed transit light curves from exoplanets and their host stars to look at the smaller dips and peaks. This helps determine the host star’s properties, such as its overall level of spottiness, inclination angle of the planet’s orbit, the tilt of the star’s spin compared to our line of sight, and other factors. Sagynbayeva’s model uses light curves that include not only transit information, but also the rotation of the star itself to provide even more detailed information about these stellar properties.
To view this video please enable JavaScript, and consider upgrading to a web browser that
supports HTML5 video
This artist’s concept illustrates the varying brightness of star with a transiting planet and several star spots. NASA’s Goddard Space Flight Center “Knowing more about the star in turn helps us learn even more about the planet, like a feedback loop,” said co-author Brett Morris, a senior software engineer at the Space Telescope Science Institute in Baltimore. “For example, at cool enough temperatures, stars can have water vapor in their atmospheres. If we want to look for water in the atmospheres of planets around those stars — a key indicator of habitability — we better be very sure that we’re not confusing the two.”
To test their model, Sagynbayeva and her team looked at transits from a planet called TOI 3884 b, located around 141 light-years away in the northern constellation Virgo.
Discovered by TESS in 2022, astronomers think the planet is a gas giant about five times bigger than Earth and 32 times its mass.
The StarryStarryProcess analysis suggests that the planet’s cool, dim star — called TOI 3384 — has concentrations of spots at its north pole, which also tips toward Earth so that the planet passes over the pole from our perspective.
Currently, the only available data sets that can be fit by Sagynbayeva’s model are in visible light, which excludes infrared observations taken by NASA’s James Webb Space Telescope. But NASA’s upcoming Pandora mission will benefit from tools like this one. Pandora, a small satellite developed through NASA’s Astrophysics Pioneers Program, will study the atmospheres of exoplanets and the activity of their host stars with long-duration multiwavelength observations. The Pandora mission’s goal is to determine how the properties of a star’s light differs when it passes through a planet’s atmosphere so scientists can better measure those atmospheres using Webb and other missions.
“The TESS satellite has discovered thousands of planets since it launched in 2018,” said Allison Youngblood, TESS project scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “While Pandora will study about 20 worlds, it will advance our ability to pick out which signals come from stars and which come from planets. The more we understand the individual parts of a planetary system, the better we understand the whole — and our own.”
Facebook logo @NASAUniverse @NASAUniverse Instagram logo @NASAUniverse By Jeanette Kazmierczak
NASA’s Goddard Space Flight Center, Greenbelt, Md.
Media Contact:
Alise Fisher
202-358-2546
alise.m.fisher@nasa.gov
NASA Headquarters, Washington
Share
Details
Last Updated Aug 25, 2025 Related Terms
Astrophysics Exoplanet Atmosphere Exoplanets Galaxies, Stars, & Black Holes Galaxies, Stars, & Black Holes Research Goddard Space Flight Center Kepler / K2 Stars TESS (Transiting Exoplanet Survey Satellite) The Universe View the full article
-
By NASA
A scanning electron microscope image of a micrometeorite impact crater in a particle of asteroid Bennu material. Credits: NASA/Zia Rahman 5 min read
NASA’s Bennu Samples Reveal Complex Origins, Dramatic Transformation
Asteroid Bennu, sampled by NASA’s OSIRIS-REx mission in 2023, is a mixture of dust that formed in our solar system, organic matter from interstellar space, and pre-solar system stardust. Its unique and varied contents were dramatically transformed over time by interactions with water and exposure to the harsh space environment.
These insights come from a trio of newly published papers based on the analysis of Bennu samples by scientists at NASA and other institutions.
Bennu is made of fragments from a larger parent asteroid destroyed by a collision in the asteroid belt, between the orbits of Mars and Jupiter. One of the papers, co-led by Jessica Barnes at the University of Arizona, Tucson, and Ann Nguyen of NASA’s Johnson Space Center in Houston and published in the journal Nature Astronomy, suggests that Bennu’s ancestor was made up of material that had diverse origins—near the Sun, far from the Sun, and even beyond our solar system.
The analyses show that some of the materials in the parent asteroid, despite very low odds, escaped various chemical processes driven by heat and water and even survived the extremely energetic collision that broke it apart and formed Bennu.
“We traced the origins of these initial materials accumulated by Bennu’s ancestor,” said Nguyen. “We found stardust grains with compositions that predate the solar system, organic matter that likely formed in interstellar space, and high temperature minerals that formed closer to the Sun. All of these constituents were transported great distances to the region that Bennu’s parent asteroid formed.”
The chemical and atomic similarities of samples from Bennu, the asteroid Ryugu (sampled by JAXA’s (the Japan Aerospace Exploration Agency) Hayabusa2 mission) and the most chemically primitive meteorites collected on Earth suggest their parent asteroids may have formed in a similar, distant region of the early solar system. Yet the differences from Ryugu and meteorites that were seen in the Bennu samples may indicate that this region changed over time or did not mix as well as some scientists have thought.
We found stardust grains with compositions that predate the solar system, organic matter that likely formed in interstellar space, and high temperature minerals that formed closer to the Sun.
Ann Nguyen
Planetary Scientist
Though some original constituents survived, most of Bennu’s materials were transformed by reactions with water, as reported in the paper co-led by Tom Zega of the University of Arizona and Tim McCoy of the Smithsonian’s National Museum of Natural History in Washington and published in Nature Geoscience. In fact, minerals in the parent asteroid likely formed, dissolved, and reformed over time.
“Bennu’s parent asteroid accumulated ice and dust. Eventually that ice melted, and the resulting liquid reacted with the dust to form what we see today, a sample that is 80% minerals that contain water,” said Zega. “We think the parent asteroid accumulated a lot of icy material from the outer solar system, and then all it needed was a little bit of heat to melt the ice and cause liquids to react with solids.”
Bennu’s transformation did not end there. The third paper, co-led by Lindsay Keller at NASA Johnson and Michelle Thompson of Purdue University, also published in Nature Geoscience, found microscopic craters and tiny splashes of once-molten rock – known as impact melts – on the sample surfaces, signs that the asteroid was bombarded by micrometeorites. These impacts, together with the effects of solar wind, are known as space weathering and occurred because Bennu has no atmosphere to protect it.
“The surface weathering at Bennu is happening a lot faster than conventional wisdom would have it, and the impact melt mechanism appears to dominate, contrary to what we originally thought,” said Keller. “Space weathering is an important process that affects all asteroids, and with returned samples, we can tease out the properties controlling it and use that data and extrapolate it to explain the surface and evolution of asteroid bodies that we haven’t visited.”
Ann Nguyen, co-lead author of a new paper that gives insights into the diverse origin of asteroid Bennu’s “parent” asteroid works alongside the NanoSIMS 50L (nanoscale secondary ion mass spectrometry) ion microprobe in the Astromaterials Research and Exploration Science Division at NASA’s Johnson Space Center in Houston. Credit: NASA/James Blair As the leftover materials from planetary formation 4.5 billion years ago, asteroids provide a record of the solar system’s history. But as Zega noted, we’re seeing that some of these remnants differ from what has been found in meteorites on Earth, because certain types of asteroids burn up in the atmosphere and never make it to the ground. That, the researchers point out, is why collecting actual samples is so important.
“The samples are really crucial for this work,” Barnes said. “We could only get the answers we got because of the samples. It’s super exciting that we’re finally able to see these things about an asteroid that we’ve been dreaming of going to for so long.”
The next samples NASA expects to help unravel our solar system’s story will be Moon rocks returned by the Artemis III astronauts.
NASA’s Goddard Space Flight Center provided overall mission management, systems engineering, and the safety and mission assurance for OSIRIS-REx. Dante Lauretta of the University of Arizona, Tucson, is the principal investigator. The university leads the science team and the mission’s science observation planning and data processing. Lockheed Martin Space in Littleton, Colorado, built the spacecraft and provided flight operations. Goddard and KinetX Aerospace were responsible for navigating the OSIRIS-REx spacecraft. Curation for OSIRIS-REx takes place at NASA’s Johnson Space Center in Houston. International partnerships on this mission include the OSIRIS-REx Laser Altimeter instrument from the Canadian Space Agency and asteroid sample science collaboration with JAXA’s Hayabusa2 mission. OSIRIS-REx is the third mission in NASA’s New Frontiers Program, managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama, for the agency’s Science Mission Directorate in Washington.
Melissa Gaskill
Johnson Space Center
For more information on NASA’s OSIRIS-REx mission, visit:
https://science.nasa.gov/mission/osiris-rex/
Karen Fox / Molly Wasser
Headquarters, Washington
202-358-1600
karen.c.fox@nasa.gov / molly.l.wasser@nasa.gov
Victoria Segovia
Johnson Space Center
(281) 483-5111
victoria.segovia@nasa.gov
View the full article
-
By NASA
A collaboration between NASA and the small business Aloft Sensing produced a new compact radar system that will enable researchers to leverage High Altitude Long Endurance (HALE) platforms to observe dynamic Earth systems. This new radar is small, provides highly sensitive measurements, and doesn’t require GPS for positioning; eventually, it could be used on vehicles in space.
HALE InSAR flies aboard a high-altitude balloon during a test-flight. This lightweight instrument will help researchers measure ground deformation and dynamic Earth systems. Credit: Aloft Sensing Long before a volcano erupts or a mountainous snowpack disappears, millimeter-scale changes in Earth’s surface indicate larger geologic processes are at work. But detecting those minute changes, which can serve as early warnings for impending disasters, is difficult.
With support from NASA’s Earth Science Technology Office (ESTO ) a team of researchers from the small aerospace company Aloft Sensing is developing a compact radar instrument for observing Earth’s surface deformation, topography, and vegetation with unprecedented precision.
Their project, “HALE InSAR,” has demonstrated the feasibility of using high-altitude, long-endurance (HALE) vehicles equipped with Interferometric Synthetic Aperture Radar (InSAR) to observe changes in surface deformation mere millimeters in size and terrain information with centimetric vertical accuracy.
“It’s a level of sensitivity that has eluded traditional radar sensors, without making them bulky and expensive,” said Lauren Wye, CEO of Aloft Sensing and principal investigator for HALE InSAR.
HALE vehicles are lightweight aircraft designed to stay airborne for extended periods of time, from weeks to months and even years. These vehicles can revisit a scene multiple times an hour, making them ideal for locating subtle changes in an area’s geologic environment.
InSAR, a remote sensing technique that compares multiple images of the same scene to detect changes in surface topography or determine structure, is also uniquely well-suited to locate these clues. But traditional InSAR instruments are typically too large to fly aboard HALE vehicles.
HALE InSAR is different. The instrument is compact enough for a variety of HALE vehicles, weighing less than 15 pounds (seven kilograms) and consuming fewer than 300 watts of power, about as much energy as it takes to power an electric bike.
HALE InSAR leverages previously-funded NASA technologies to make such detailed measurements from a small platform: a novel electronically steered antenna and advanced positioning algorithms embedded within an agile software-defined transceiver. These technologies were developed under ESTO’s Instrument Incubation Program (IIP) and Decadal Survey Incubation (DSI) Program, respectively.
“All of the design features that we’ve built into the instrument are starting to showcase themselves and highlight why this payload in particular is distinct from what other small radars might be looking to achieve,” said Wye.
One of those features is a flat phased array antenna, which gives users the ability to focus HALE InSAR’s radar beam without physically moving the instrument. Using a panel about the size of a tablet computer, operators can steer the beam electronically, eliminating the need for gimbles and other heavy components, which helps enable the instrument’s reduced size and weight.
A close up HALE InSAR fixed to a high-altitude airship. The flat planar antenna reduces the instruments mass and eliminates the need for gimbles and other heavy components. Credit: Aloft Sensing “SAR needs to look to the side. Our instrument can be mounted straight down, but look left and right on every other pulse such that we’re collecting a left-looking SAR image and a right-looking SAR image essentially simultaneously. It opens up opportunities for the most mass-constrained types of stratospheric vehicles,” said Wye.
Using advanced positioning algorithms, HALE InSAR also has the unique ability to locate itself without GPS, relying instead on feedback from its own radar signals to determine its position even more accurately. Brian Pollard, Chief Engineer at Aloft Sensing and co-investigator for HALE InSAR, explained that precise positioning is essential for creating high-resolution data about surface deformation and topography.
“SAR is like a long exposure camera, except with radio waves. Your exposure time could be a minute or two long, so you can imagine how much smearing goes on if you don’t know exactly where the radar is,” said Pollard.
Navigating without GPS also makes HALE InSAR ideal for field missions in austere environments where reliable GPS signals may be unavailable, increasing the instrument’s utility for national security applications and science missions in remote locations.
The Aloft Sensing team recently achieved several key milestones, validating their instrument aboard an airship at 65,000 feet as well as small stratospheric balloons. Next, they’ll test HALE InSAR aboard a fixed wing HALE aircraft. A future version of their instrument could even find its way into low Earth orbit on a small satellite.
Wye credits NASA support for helping her company turn a prototype into a proven instrument.
“This technology has been critically enabled by ESTO, and the benefit to science and civil applications is huge,” said Wye. “It also exemplifies the dual-use potential enabled by NASA-funded research. We are seeing significant military interest in this capability now that it is reaching maturity. As a small business, we need this hand-in-hand approach to be able to succeed.”
For more information about opportunities to work with NASA to develop new Earth observation technologies, visit esto.nasa.gov.
For additional details, see the entry for this project on NASA TechPort.
Project Lead: Dr. Lauren Wye, CEO, Aloft Sensing
Sponsoring Organization: NASA’s Instrument Incubation Program (IIP)
Share
Details
Last Updated Aug 19, 2025 Related Terms
Earth Science Division Earth Science Technology Office Science-enabling Technology Technology Highlights Explore More
1 min read Snapshot Wisconsin Celebrates 10 Years and 100 Million Photos Collected!
The Snapshot Wisconsin project recently collected their 100 millionth trail camera photo! What’s more, this…
Article
2 weeks ago
2 min read Polar Tourists Give Positive Reviews to NASA Citizen Science in Antarctica
Article
1 month ago
7 min read A New Alloy is Enabling Ultra-Stable Structures Needed for Exoplanet Discovery
Article
2 months ago
View the full article
-
By NASA
Explore This Section Earth Earth Observer Editor’s Corner Feature Articles Meeting Summaries News Science in the News Calendars In Memoriam Announcements More Archives Conference Schedules Style Guide 21 min read
A Decade of Global Water Cycle Monitoring: NASA Soil Moisture Active Passive Mission
Introduction
The NASA Soil Moisture Active Passive (SMAP) mission, launched in 2015, has over 10 years of global L-band radiometry observations. The low frequency [1.4 GHz frequency or 21 cm (8 in) wavelength] measurements provide information on the state of land surfaces in all weather conditions – regardless of solar illumination. A principal objective of the SMAP mission is to provide estimates of surface soil moisture and its frozen or thawed status. Over the land surface, soil moisture links the water, energy, and carbon cycles. These three cycles are the main drivers of regional climate and regulate the functioning of ecosystems.
The achievement of 10 years in orbit is a fitting time to reflect on what SMAP has accomplished. After briefly discussing the innovative measurement approach and the instrument payload (e.g., a radiometer and a regrettably short-lived L-band radar), a significant section of this article is devoted to describing the mission’s major scientific achievements and how the data from SMAP have been used to serve society (e.g., applied sciences) – including SMAP’s pathfinding role as Early Adopters. This content is followed by a discussion of how SMAP has dealt with issues related to radio frequency interference in the L-Band region, a discussion of the SMAP data products suite, future plans for the SMAP active–passive algorithm, and a possible follow-on L-band global radiometry mission being developed by the European Union’s Copernicus Programme that would allow for data continuity beyond SMAP. This summary for The Earth Observer is excerpted from a longer and more comprehensive paper that, as of this article’s posting, is being prepared for publication in the Proceedings of the Institute of Electrical and Electronics Engineers (IEEE).
SMAP Measurement Approach and Instruments
The SMAP primary and operating instrument is the L-band radiometer, which collects precise surface brightness temperature data. The radiometer includes advanced radio frequency interference (RFI) detection and mitigation hardware and software. The radiometer measures vertical and horizontal polarization observations along with the third and fourth Stokes parameters (T3 and T4) of the microwave radiation upwelling from the Earth. The reflector boom and assembly, which includes a 6 m (20 ft) deployable light mesh reflector, is spun at 14.6 revolutions-per-minute, which creates a 1000 km (621 mi) swath as the SMAP satellite makes its Sun-synchronous orbit of the Earth – see Figure 1. This approach allows coverage of the entire globe in two to three days with an eight-day exact repeat. The radiometer instrument is calibrated monthly by pointing it to the deep sky.
Figure 1. An artist’s rendering of the SMAP Observatory showing both the radiometer and radar. Figure credit: NASA/Jet Propulsion Laboratory/California Institute of Technology The original SMAP instrument design included a companion L-band radar, which operated from April through early July 2015, acquiring observations of co- and cross-polarized radar backscatter at a spatial resolution of about 1 km (0.6 mi) with a temporal revisit of about three days over land. This data collection revealed the dependence of L-band radar signals on soil moisture, vegetation water content, and freeze thaw state. The radar transmitter failed on July 7, 2015. Shortly thereafter, the radar receiver channels were repurposed to record the reflected signals from the Global Navigation Satellite System (GNSS) constellation in August 2015, making SMAP the first full-polarimetric GNSS reflectometer in space for the investigation of land surface and cryosphere.
Scientific Achievements from a Decade of SMAP Data
A decade of SMAP soil moisture observations have led to a plethora of scientific achievements. The data have been used to quantify the linkages of the three main metabolic cycles (e.g., carbon, water, and energy) on land. They have also been used to improve drought assessments and flood prediction as well as the accuracy of numerical weather prediction (NWP) models. They are also used to measure liquid water and thickness of ice sheets, and sea surface salinity. The subsections that follow describe how SMAP data are being put to use in myriad ways that benefit society.
Quantifying Processes that Link the Terrestrial Water, Energy, and Carbon Cycles
The primary SMAP science goal is to develop observational benchmarks of how the water, energy, and carbon cycles link together over land. Soil moisture is the variable state of the land branch of the water cycle. It links the water cycle to the energy cycle through limiting latent heat flux – the change in energy as heat exchanges when water undergoes a phase change, such as evapotranspiration at the land–atmosphere interface. Soil moisture also links the water and carbon cycles, which is evident through plant photosynthesis. SMAP global observations of soil moisture fields, in conjunction with remote sensing of elements of the energy and carbon cycles, can reveal how these three cycles are linked in the real world as a benchmark for weather and Earth system models.
Photosynthesis is down-regulated by both the deficit in water availability and the lack of an adequate amount of photosynthetically active radiation. Global maps reveal how soil moisture and light regulate photosynthesis – see Figure 2. These benchmark observational results can be used to assess how Earth system models link to the three main metabolic cycles of the climate system.
Figure 2. Observed regulation of photosynthesis by water availability [left] and light availability [right]. Blue denotes greater limitation. Photosynthesis rates for both maps determined using solar-induced fluorescence (SIF) measurements (mW/m2 nm sr) from the Tropospheric Ozone Monitoring Instrument (TROPOMI) on the European Union’s Copernicus Sentinel-5P mission. Water availability was determined using soil moisture (SM) measurements from the Soil Moisture Active Passive (SMAP) mission. Light availability was determined using measurements of photosynthetically active radiation (PAR) from the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra and Aqua platforms. The resulting maps show the model slope (mW/m2/nm/sr) of the estimated SIF-SM relationship in the water-limited regime [left] and the model slope (10-3/nm/sr) of estimated SIF-PAR relationship in the light-limited regime [right]. Figure credit: Jonard et al (2022) in Biogeosciences Development of Improved Flood Prediction and Drought Monitoring Capability
SMAP products have also been widely used in applied sciences and natural hazard decision-support systems. SMAP’s observation-based soil moisture estimates offer transformative information for managing water-related natural hazards, such as monitoring agricultural drought – defined as a persistent deficit in soil moisture – and flood volumes – defined as the landscape’s water absorption capacity during precipitation events. The SMAP project produces a parallel, near-real-time data stream that is accessed by a number of federal and state agencies in decision-support systems related to drought monitoring, food security, and landscape inundation and trafficability.
Enhancing Weather and Climate Forecasting Skill
SMAP’s enhancement of numerical weather prediction, model skill, and reduction of climate model projection uncertainties is based on the premise of the contribution of solar energy to weather and climate dynamics. Soil moisture has a strong influence on how available solar energy is partitioned into components (e.g., sensible heat flux versus latent heat flux) over land. The influence propagates through the atmospheric boundary layer and ultimately influences the evolution of weather.
To give an example, land surface processes can affect the evolution of the U.S. Great Plains low-level jets (GPLLJs). These jets drive mesoscale convective weather systems. Previous studies have shown that GPLLJs are sensitive to regional soil moisture gradients. Assimilation of SMAP soil moisture data improves forecasts of weakly synoptically forced or uncoupled GPLLJs compared to forecasts of cyclone-induced coupled GPLLJs. For example, the NASA Unified Weather Research and Forecasting Model, with 75 GPLLJs at 9 km (5.6 mi) resolution both with and without SMAP soil moisture data assimilation [SMAP data assimilation (DA) and no-DA respectively], shows how the windspeed mean absolute difference between SMAP DA and no-DA increase approximately linearly over the course of the simulation with maximum differences at 850 hPa (or mb) for the jet entrance and core – see Figure 3.
Figure 3. The impact of adding soil moisture data [SMAP data assimilation (DA) minus no-DA] to a model simulation from theNASA Unified Weather Research and Forecasting Model (NU-WRF)) of the Great Plains Low Level Jet (GPLLJ). The results show the mean over 75 independent GPLLJ events. The plots correspond to wind speed difference with height (y-axis) and time (hours on x-axis). The panels are for jet entrance [left], jet core [middle] and jet exit [right]. Soil moisture data assimilation enhances the intensity of the simulated GPLLJ. The stippling corresponds to 99% statistical confidence. Figure credit: Ferguson (2020) in Monthly Weather Review Measuring Liquid Water Content and Thickness of Ice Sheets
The mass loss of Greenland and Antarctica ice sheets contributes to sea-level rise – which is one of the most impactful and immediate damaging consequences of climate change. The melt rates over the last few years have raised alarm across the globe and impact countries with coastal communities. The cryosphere community has raised a call-to-action to use every observing system and model available to monitor the patterns and rates of land ice melt.
Surface melt affects the ice cap mass loss in many ways: the direct melt outflow from the ablation zone of the Greenland ice sheet, the structural change of the percolation zone of the Greenland ice sheet, changes in the melt water retention and outflow boundaries, changes in the structure of the Antarctic ice shelves, and destabilization of the buttressing of the glacier outflow through various processes (e.g., hydrofracturing and calving). The long-term climate and mass balance models rely on accurate representation of snow, firn, and ice processes to project the future sea level.
The SMAP L-band radiometer has relatively long wavelength [21 cm (8 in)] observations compared to other Earth-observing instruments. It enables the measurement of liquid water content (LWC) in the ice sheets and shelves as it receives the radiation from the deep layers of the snow/firn/ice column. Relatively high LWC values absorb the emission only partially, making the measurement sensitive to different liquid water amounts (LWA) in the entire column. Figure 4 shows the cumulative LWA for 2015–2023 based on SMAP measurements.
Figure 4. Total annual sum of SMAP daily liquid water amount (LWA) for 2015–2023. The black solid line on each map represents grid edges, and the grey color mask inside the ice sheet indicates melt detections by decreasing brightness temperature. Figure Credit: Andreas Colliander [Finnish Meteorological Institute]. The SMAP L-band radiometer has also been used to derive the thickness of thin sea ice [Soil Moisture and Ocean Salinity (SMOS) mission have been recalibrated to SMAP, using the same fixed incidence angle. The data show strong agreement and demonstrate clear benefits of a combined dataset. The L-band thin ice thickness retrievals provide a useful complement to higher-resolution profiles of thicker ice obtained from satellite altimeters (e.g. ESA’s CryoSat-2 and NASA’s Ice, Clouds and land Elevation Satellite–2 missions).
Extending and Expanding the Aquarius Sea Surface Salinity Record
The joint NASA/Argentinian Aquarius/Satélite de Aplicaciones Científicas (SAC)-D (Aquarius), which operated from 2011–2015, used an L-band radiometer and an L-band scatterometer to make unprecedented monthly maps of global sea surface salinity at 150-km (93-mi) resolution. The SMAP L-band radiometer has not only extended the sea surface salinity record in the post-Aquarius period, it has also increased the spatial resolution and temporal frequency of these measurements because of its larger reflector and wider swath. The increased resolution and revisit allow new and unprecedented perspectives into mixing and freshwater events, coastal plume tracking, and other more local oceanic features.
Providing New Perspectives on Global Ecology and Plant Water Stress
The L-band vegetation optical depth (VOD) – which is related to water content in vegetation – has been retrieved simultaneously with soil moisture using SMAP’s dual-polarized brightness temperatures and is being used to better understand global ecology. Water in above-ground vegetative tissue attenuates and thus depolarizes surface microwave emission, and VOD quantifies this effect. SMAP can provide global observations of VOD in all weather conditions with a two to three day temporal frequency. Changes in VOD indicate either plant rehydration or growth. Ecologists benefit from this new ecosystem observational data, which augments optical and near-infrared vegetation indices [e.g., leaf area index (LAI)] and has a higher temporal frequency that is not affected by clouds and does not saturate as rapidly for dense vegetation.
Examples of how the data have been used include deciphering the conditions when vegetation uptakes soil water only for rehydration (i.e., VOD increase with no LAI change) compared to plant growth (i.e., increase in both VOD and LAI). The applications of VOD are increasing and the ecology community views this product as a valuable additional perspective on soil–plant water relations.
At the moment, this measurement has no ground-based equivalent. Therefore, field experiments with airborne instruments and ground sampling teams are needed to firmly establish the product as a new observational capability for global ecology.
Applied Science Collaboration: SMAP Observations Serving Society
The SMAP project has worked with the NASA Earth Science Division Applied Sciences Program (now known as Earth Science to Action) and the natural hazards monitoring and forecasting communities for pre- and post-launch implementation of SMAP products in their operations. In some operational applications, for which long-term data continuity is a requirement, the SMAP data are still used for assessment of current conditions, as well as research and development.
The Original Early Adopters
Prior to its launch, the SMAP mission established a program to explore and facilitate applied and operational uses of SMAP mission data products in decision-making activities for societal benefit. To help accomplish these objectives, SMAP was the first NASA mission to create a formal Applications Program and an Early Adopter (EA) program, which eventually became a requirement for all future NASA Earth Science directed satellite missions. SMAP’s EA program increases the awareness of mission products, broadens the user community, increases collaboration with potential users, improves knowledge of SMAP data product capabilities, and expedites the distribution and uses of mission products after launch.
SMAP Data in Action
Several project accomplishments have been achieved primarily through an active continuous engagement with EAs and operational agencies working towards national interests. SMAP soil moisture data have been used by the U.S. Department of Agriculture (USDA) for domestic and international crop yield applications. For example the USDA’s National Agricultural Statistics Service (NASS) conducts a weekly survey of crop progress, crop condition, and soil moisture condition for U.S. cropland. NASS surveys and publishes state-level soil moisture conditions in the NASS Crop Progress Report.
The traditional field soil moisture survey is a large-scale, labor-intensive data collection effort that relies heavily on responses from farmers, agricultural extension agents and/or other domain experts for field observations. One weakness of these observations is that they are based on subjective assessments rather than quantitative measures and can lead to spatial inconsistency based on the human responses from the respective counties. Moreover, the NASS Crop Progress Reports do not provide specific geolocation information for the assessed soil moisture conditions – which are extremely useful metadata to provide to data users. NASS implemented the use of SMAP observations in their weekly reports during the growing period (March–November). SMAP maps estimated root-zone soil moisture for the week of November 14–20, 2022, over NASS Pacific (California and Nevada) and Delta (Arkansas, Mississippi and Louisiana) regional domains—see Figure 5.
Figure 5. SMAP-based soil moisture estimates for California, Nevada, Arkansas, Mississippi, and Louisiana, used by the U.S. Department of Agriculture’s (USDA) National Agricultural Statistics Service (NASS) in their weekly report covering November 14–20, 2022. These data are available for selected states at the NASS website linked in the text. Figure Credit: NASS SMAP Radio Frequency Interference Detection and Mitigation
Although SMAP operates within the protected frequency allocation of 1400–1427 MHz, the radiometer has been impacted by radio frequency interference over the mission lifetime. Unauthorized in-band transmitters as well as out-of-band emissions from transmitters operating adjacent to the allocated spectrum have been observed in SMAP measurements since its launch. The previously launched SMOS and Aquarius radiometers provide evidence of global RFI at L-band. Consequently, SMAP was designed to incorporate a novel onboard digital detector on the back end to enable detection and filtering of RFI. The radiometer produces science data in time and frequency, enabling the use of multiple RFI detection methods in the ground processing software.
On-orbit data demonstrate that the RFI detection and filtering performs well and improves the quality of SMAP brightness temperature measurements. The algorithms are most effective at filtering RFI that is sparse in time and frequency, with minimal impact on the noise equivalent delta temperature (NEDT) – a measure of the radiometer sensitivity. Some areas of the globe remain problematic as RFI that is very high level and persistent results in high percentages of data loss due to removal of contaminated data. A global map of RFI detection rate for January 2025 shows a large contrast between Eastern and Western Hemispheres and between Northern and Southern Hemispheres – see Figure 6. Regions of isolated RFI and severe RFI correspond to populated areas. A detection rate of 100% means all pixels are flagged and removed, resulting in data loss. Analysis of spectral information reveal many sources are likely terrestrial radar systems; however, many wideband, high-level sources and low-level, non-radar sources also persist. Over areas of geopolitical conflict, the time-frequency data show interference covering the entire radiometer receiver bandwidth.
Figure 6. Percentage of pixels on a 0.25° grid for January 2025 that have been flagged for removal by the Soil Moisture Active Passive radio frequency interference detection algorithms. Figure Credit: Priscilla N. Mohammed [GSFC] The RFI challenge is further addressed through official spectrum management channels and formal reports that include the geolocated coordinates of sources, interference levels, frequency of occurrence during the observed period, and spectral information – all of which aid field agents as they work to identify potential offenders. Reports are submitted to the NASA Spectrum office and then forwarded to the country of interest through the Satellite Interference Reporting and Resolution System.
SMAP Science Data Products
The current suite of SMAP science data products is available in the Table. The principal data products are grouped in four levels designated as L1–4. The L1 products are instrument L-band brightness temperature in Kelvin and include all four Stokes parameters (i.e., horizonal and vertical polarization as well as third and fourth Stokes). Both 6:00 AM equatorial crossing (descending) and 6:00 PM equatorial crossing (ascending data) are contained in the products. The user has access to quality flags of the conditions under which measurements are available for each project. The L1B products are time-ordered and include fore and aft measurements. L1C products are on the Equal-Area Scalable Earth V2 (EASE2) grid with polar and global projections. L2 data products are geophysical retrievals (i.e., soil moisture, VOD, and binary freeze/thaw classification on a fixed Earth grid). The L2 half-orbit products are available to the public within a day of acquisition. L3 products are daily composites and include all half-orbits for that day.
The SMAP project also produces L4 data that are the result of data assimilation. The L4 products take advantage of other environmental observations, such as precipitation, air temperature and humidity, radiative fluxes at the land surface, and ancillary land use and soil texture information, to produce estimates of surface [nominally 0–5 cm (0–2 in)] and subsurface (e.g., root-zone up to a meter) soil moisture. The data assimilation system is a merger of model and measurements and hence resolves the diurnal cycle of land surface conditions. The data assimilation system also provides estimates of surface fluxes of carbon, energy, and water, such as evaporation, runoff, gross primary productivity (GPP), and respiration. The difference between GPP and respiration is the net ecosystem exchange, which is the net source/sink of the carbon cycle over land.
The SMAP suite of products also include near-real-time (NRT) brightness temperature and soil moisture products for use in operational weather forecast applications. The NRT product targets delivery to users within three hours of measurement acquisition. The NRT uses predicted SMAP antenna pointing (instead of telemetry) and model predicted ancillary data (soil temperature) in order to support operational centers that require more than three hours of data products for updating weather forecast models. To date SMAP has met its required and target (for NRT) latency requirements.
Two other data projects merge synergistically with other (colocated) satellite measurements. The SPL2SMAP_S merges SMAP L-band radio brightness measurements with C-band synthetic aperture radar (SAR) measurements from the ESA Copernicus Sentinel-1 mission. The SAR data have high resolution and allow the generation of 1 and 3 km (0.62 and 1.8 mi) merged surface soil moisture estimates. The high resolution soil moisture information, however, is only available when there is coincident SMAP and Sentinel-1 measurements. The refresh rate of this product is limited and can be as long as 12 days.
The merged SMOS–SMAP passive L-band radiometry data allows the generation of global, near daily surface soil moisture estimates, which are required to resolve fast hydrologic processes, such as gravity drainage and recharge flux. These parameters are only partially resolved with the SMAP, with a two to three day data refresh rate. This product interpolates the multi-angular SMOS data to the SMAP 40º incident angle and uses all SMAP algorithms, including correction of waterbody impact on SMAP brightness temperature, and ancillary data for geophysical inversions to soil moisture and VOD, ensuring consistency. The combined SMAP–SMOS data product may not be available daily across locations, such as Japan, parts of China, and the Middle East, where RFI affects data collection.
Table. Soil Moisture Active Passive suite of science products are available through the National Snow and Ice Data Center, one of NASA’s Distributed Active Archive Centers.
Product Type Product description Resolution (Gridding) Granule Extent SPL1BTB Geolocated, calibrated brightness temperature in time order 36 km Half Orbit SPL1CTB_E Backus-Gilbert interpolated, calibrated brightness temperature in time order (9 km) Half Orbit SPL1CTB Geolocated, calibrated brightness temperature on Equal-Area Scalable Earth V2 (EASE2) grid 36 km Half Orbit SPL1CTB_E Backus-Gilbert interpolated, calibrated brightness temperature on EASE2 grid (9 km) Half Orbit SPL2SMP Radiometer soil moisture and vegetation optical depth 36 km Half Orbit SPL2SMP_E Radiometer soil moisture and vegetation optical depth based on SPL1CTB (9 km) Half Orbit SPL2SMAP_S SMAP radiometer/Copernicus Sentinel-1 soil moisture 3 km Sentinel-1 SPL3SMP Daily global composite radiometer soil moisture and vegetation optical depth based on SPL1CTB 36 km Daily–Global SPL3SMP_E Daily global composite radiometer soil moisture and vegetation optical depth based on SPL1CTB_E (9 km) Daily–Global SPL3FTP Daily composite freeze/thaw state based on SPL1CTB 36 km Daily–Global SPL3FTP_E Daily composite freeze/thaw state based on SPL1CTB_E (9 km) Daily–Global SPL4SMAU Surface and Root Zone soil moisture 9 km 3 hours – Global SPL4CMDL Carbon Net Ecosystem Exchange 9 km Daily–Global SPL1BTB_NRT Near Real Time Geolocated, calibrated brightness temperature in time order 36 km Half Orbit SPL2SMP_NRT Near Real Time Radiometer soil moisture 36 km Half Orbit L2/L3 SMOS SM SMOS soil moisture and VOD based on SMAP algorithms (9 km) Half Orbit/Daily Global Future Directions for the SMAP Active–Passive Algorithm
Although the SMAP radar failed not long after launch, the data that were collected have been used to advance the development of the SMAP Active–Passive (AP) algorithm, which will be applied to the combined SMAP radiometer data and radar data from the NASA–Indian Space Research Organisation (ISRO) Synthetic Aperture Radar [NISAR] mission, a recently-launched L-Band Synthetic Aperture mission to produce global soil moisture at a spatial resolution of 1 km (0.62 mi) or better. The high resolution product can advance applications of SMAP data (e.g., agricultural productivity, wildfire, and landslide monitoring).
Data Continuity Beyond SMAP
A forthcoming mission meets some – but not all – of the SMAP measurement requirements and desired enhancements. The European Union’s Copernicus Program Copernicus Imaging Microwave Radiometer (CIMR) mission is a proposed multichannel microwave radiometry observatory that includes L-band and four other microwave channels sharing a large mesh reflector. The mesh reflector is similar to the one that is used on SMAP, but larger. The successful SMAP demonstration of rotating large deployable mesh antennas for Earth observations has been useful to the CIMR design.
In terms of RFI detection capability, CIMR will also use an approach that is similar to SMAP. With regard to instrument thermal noise (NEDT) and data latency, CIMR meets or comes close to the next-mission desired characteristics and equals or exceeds SMAP in most of the attributes. The native L-band resolution of CIMR is ~60 km (37 mi); however, the measurements are coincident and higher-resolution measurements in this configuration allow reconstruction of L-band radiometry at higher resolution than CIMR’s L-band. It may be possible to combine the L- and C-bands and achieve a reconstructed ~15 km (9 mi) L-band product based on the coincident and overlapping measurements. A refresh rate of one day is possible with the wide-swath characteristic of CIMR.
CIMR is currently in development; the first version, CIMR-1A, is expected to launch within this decade and the second version, CIMR-1B, in the mid 2030s. Since the Copernicus program supports operational activities (e.g., numerical weather prediction), the program includes plans for follow-on CIMR observatories so that the data record will be maintained without gaps in the future.
Conclusions
The SMAP mission was launched in 2015 and has produced over 10 years of science data. Because of its unique instrument and operating characteristics, the global low-frequency microwave radiometry with the SMAP observatory has resulted in surface soil moisture, vegetation optical depth, and freeze/thaw state estimates that outperform past and current products. The data have been widely used in the Earth system science community and also applied to natural hazards applications.
The Earth system science and application communities are actively using the decade-long, high-quality global L-band radiometry. The intensity and range of SMAP science data usage is evident in the number of peer-reviewed journal publications that contain SMAP or Soil Moisture Active Passive in their title or abstract and use SMAP data in the study (i.e., search: www.webofscience.com data-base). The authors acknowledge that many publications escape this particular query approach. Currently the bibliography includes over 1700 entries and over 20,000 citations spanning several elements of Earth system science, including hydrologic science and regional and global water cycle, oceanic and atmospheric sciences, cryosphere science, global ecology as well as microwave remote sensing technologies.
To Learn More About SMAP
A more comprehensive bibliography of studies published based on SMAP data products, a set of one-page SMAP science and applications highlights in standardized format, and SMAP project documents including assessment reports are all available online via the links provided.
Acknowledgements
The authors wish to acknowledge the contributions of the SMAP Science Team, the SMAP Algorithm Development Team, and the SMAP Project Office engineers and staff. All of these teams contribute to the ongoing SMAP science product generation and uses reported in this article.
Dara Entekhabi
Massachusetts Institute of Technology
darae@mit.edu
Simon Yueh
Jet Propulsion Laboratory/California Institute of Technology
simon.h.yueh@jpl.nasa.gov
Rajat Bindlish
NASA Goddard Space Flight Center
rajat.bindlish@nasa.gov
Mark Garcia
Jet Propulsion Laboratory/California Institute of Technology
mark.d.garcia@jpl.nasa.gov
Jared Entin
NASA Headquarters
jared.k.entin@nasa.gov
Craig Ferguson
NASA Headquarters
craig.r.ferguson@nasa.gov
Share
Details
Last Updated Aug 18, 2025 Related Terms
Earth Science View the full article
-
-
Check out these Videos
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.