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Plato’s cave: vacuum test for exoplanet detection
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Explore This Section Webb News Latest News Latest Images Webb’s Blog Awards X (offsite – login reqd) Instagram (offsite – login reqd) Facebook (offsite- login reqd) Youtube (offsite) Overview About Who is James Webb? Fact Sheet Impacts+Benefits FAQ Science Overview and Goals Early Universe Galaxies Over Time Star Lifecycle Other Worlds Observatory Overview Launch Deployment Orbit Mirrors Sunshield Instrument: NIRCam Instrument: MIRI Instrument: NIRSpec Instrument: FGS/NIRISS Optical Telescope Element Backplane Spacecraft Bus Instrument Module Multimedia About Webb Images Images Videos What is Webb Observing? 3d Webb in 3d Solar System Podcasts Webb Image Sonifications Team International Team People Of Webb More For the Media For Scientists For Educators For Fun/Learning 6 Min Read NASA’s Webb Lifts Veil on Common but Mysterious Type of Exoplanet
This artist’s concept shows what the hot sub-Neptune exoplanet TOI-421 b could look like. It is based on spectroscopic data gathered by Webb, as well as previous observations from other telescopes on the ground and in space. Credits:
Illustration: NASA, ESA, CSA, Dani Player (STScI) Though they don’t orbit around our Sun, sub-Neptunes are the most common type of exoplanet, or planet outside our solar system, that have been observed in our galaxy. These small, gassy planets are shrouded in mystery…and often, a lot of haze. Now, by observing exoplanet TOI-421 b, NASA’s James Webb Space Telescope is helping scientists understand sub-Neptunes in a way that was not possible prior to the telescope’s launch.
“I had been waiting my entire career for Webb so that we could meaningfully characterize the atmospheres of these smaller planets,” said principal investigator Eliza Kempton of the University of Maryland, College Park. “By studying their atmospheres, we’re getting a better understanding of how sub-Neptunes formed and evolved, and part of that is understanding why they don’t exist in our solar system.”
Image A: Artist’s Concept of TOI-421 b
This artist’s concept shows what the hot sub-Neptune exoplanet TOI-421 b could look like. It is based on spectroscopic data gathered by Webb, as well as previous observations from other telescopes on the ground and in space. Illustration: NASA, ESA, CSA, Dani Player (STScI) Small, Cool, Shrouded in Haze
The existence of sub-Neptunes was unexpected before they were discovered by NASA’s retired Kepler space telescope in the last decade. Now, astronomers are trying to understand where these planets came from and why are they so common.
Before Webb, scientists had very little information on them. While sub-Neptunes are a few times larger than Earth, they are still much smaller than gas-giant planets and typically cooler than hot Jupiters, making them much more challenging to observe than their gas-giant counterparts.
A key finding prior to Webb was that most sub-Neptune atmospheres had flat or featureless transmission spectra. This means that when scientists observed the spectrum of the planet as it passed in front of its host star, instead of seeing spectral features – the chemical fingerprints that would reveal the composition of the atmosphere – they saw only a flat-line spectrum. Astronomers concluded from all of those flat-line spectra that at least certain sub-Neptunes were probably very highly obscured by either clouds or hazes.
Image B: Spectrum of TOI-421 b
A transmission spectrum captured by NASA’s James Webb Space Telescope reveals chemicals in the atmosphere of the hot sub-Neptune exoplanet TOI-421 b. Illustration: NASA, ESA, CSA, Joseph Olmsted (STScI) A Different Kind of Sub-Neptune?
“Why did we observe this planet, TOI-421 b? It’s because we thought that maybe it wouldn’t have hazes,” said Kempton. “And the reason is that there were some previous data that implied that maybe planets over a certain temperature range were less enshrouded by haze or clouds than others.”
That temperature threshold is about 1,070 degrees Fahrenheit. Below that, scientists hypothesized that a complex set of photochemical reactions would occur between sunlight and methane gas, and that would trigger the haze. But hotter planets shouldn’t have methane and therefore perhaps shouldn’t have haze.
The temperature of TOI-421 b is about 1,340 degrees Fahrenheit, well above the presumed threshold. Without haze or clouds, researchers expected to see a clear atmosphere – and they did!
A Surprising Finding
“We saw spectral features that we attribute to various gases, and that allowed us to determine the composition of the atmosphere,” said the University of Maryland’s Brian Davenport, a third-year Ph.D. student who conducted the primary data analysis. “Whereas with many of the other sub-Neptunes that had been previously observed, we know their atmospheres are made of something, but they’re being blocked by haze.”
The team found water vapor in the planet’s atmosphere, as well as tentative signatures of carbon monoxide and sulfur dioxide. Then there are molecules they didn’t detect, such as methane and carbon dioxide. From the data, they can also infer that a large amount of hydrogen is in TOI-421 b’s atmosphere.
The lightweight hydrogen atmosphere was the big surprise to the researchers. “We had recently wrapped our mind around the idea that those first few sub-Neptunes observed by Webb had heavy-molecule atmospheres, so that had become our expectation, and then we found the opposite,” said Kempton. This suggests TOI-421 b may have formed and evolved differently from the cooler sub-Neptunes observed previously.
Is TOI-421 b Unique?
The hydrogen-dominated atmosphere is also interesting because it mimics the composition of TOI-421 b’s host star. “If you just took the same gas that made the host star, plopped it on top of a planet’s atmosphere, and put it at the much cooler temperature of this planet, you would get the same combination of gases. That process is more in line with the giant planets in our solar system, and it is different from other sub-Neptunes that have been observed with Webb so far,” said Kempton.
Aside from being hotter than other sub-Neptunes previously observed with Webb, TOI-421 b orbits a Sun-like star. Most of the other sub-Neptunes that have been observed so far orbit smaller, cooler stars called red dwarfs.
Is TOI-421b emblematic of hot sub-Neptunes orbiting Sun-like stars, or is it just that exoplanets are very diverse? To find out, the researchers would like to observe more hot sub-Neptunes to determine if this is a unique case or a broader trend. They hope to gain insights into the formation and evolution of these common exoplanets.
“We’ve unlocked a new way to look at these sub-Neptunes,” said Davenport. “These high-temperature planets are amenable to characterization. So by looking at sub-Neptunes of this temperature, we’re perhaps more likely to accelerate our ability to learn about these planets.”
The team’s findings appear on May 5 in the Astrophysical Journal Letters.
The James Webb Space Telescope is the world’s premier space science observatory. Webb is solving mysteries in our solar system, looking beyond to distant worlds around other stars, and probing the mysterious structures and origins of our universe and our place in it. Webb is an international program led by NASA with its partners, ESA (European Space Agency) and CSA (Canadian Space Agency).
To learn more about Webb, visit:
https://science.nasa.gov/webb
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Laura Betz – laura.e.betz@nasa.gov
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Ann Jenkins – jenkins@stsci.edu
Space Telescope Science Institute, Baltimore, Md.
Hannah Braun – hbraun@stsci.edu
Space Telescope Science Institute, Baltimore, Md.
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Landing on the Moon is not easy, particularly when a crew or spacecraft must meet exacting requirements. For Artemis missions to the lunar surface, those requirements include an ability to land within an area about as wide as a football field in any lighting condition amid tough terrain.
NASA’s official lunar landing requirement is to be able to land within 50 meters (164 feet) of the targeted site and developing precision tools and technologies is critically important to mission success.
NASA engineers recently took a major step toward safe and precise landings on the Moon – and eventually Mars and icy worlds – with a successful field test of hazard detection technology at NASA’s Kennedy Space Center Shuttle Landing Facility in Florida.
A joint team from the Aeroscience and Flight Mechanics Division at NASA’s Johnson Space Center’s in Houston and Goddard Space Flight Center in Greenbelt, Maryland, achieved this huge milestone in tests of the Goddard Hazard Detection Lidar from a helicopter at Kennedy in March 2025.
NASA’s Hazard Detection Lidar field test team at Kennedy Space Center’s Shuttle Landing Facility in Florida in March 2025. NASA The new lidar system is one of several sensors being developed as part of NASA’s Safe & Precise Landing – Integrated Capabilities Evolution (SPLICE) Program, a Johnson-managed cross-agency initiative under the Space Technology Mission Directorate to develop next-generation landing technologies for planetary exploration. SPLICE is an integrated descent and landing system composed of avionics, sensors, and algorithms that support specialized navigation, guidance, and image processing techniques. SPLICE is designed to enable landing in hard-to-reach and unknown areas that are of potentially high scientific interest.
The lidar system, which can map an area equivalent to two football fields in just two seconds, is a crucial program component. In real time and compensating for lander motion, it processes 15 million short pulses of laser light to quickly scan surfaces and create real-time, 3D maps of landing sites to support precision landing and hazard avoidance.
Those maps will be read by the SPLICE Descent and Landing Computer, a high-performance multicore computer processor unit that analyzes all SPLICE sensor data and determines the spacecraft’s velocity, altitude, and terrain hazards. It also computes the hazards and determines a safe landing location. The computer was developed by the Avionics Systems Division at Johnson as a platform to test navigation, guidance, and flight software. It previously flew on Blue Origin’s New Shepard booster rocket.
The NASA team prepares the Descent and Landing Computer for Hazard Detection Lidar field testing at Kennedy Space Center. NASA For the field test at Kennedy, Johnson led test operations and provided avionics and guidance, navigation, and control support. Engineers updated the computer’s firmware and software to support command and data interfacing with the lidar system. Team members from Johnson’s Flight Mechanics branch also designed a simplified motion compensation algorithm and NASA’s Jet Propulsion Laboratory in Southern California contributed a hazard detection algorithm, both of which were added to the lidar software by Goddard. Support from NASA contractors Draper Laboratories and Jacobs Engineering played key roles in the test’s success.
Primary flight test objectives were achieved on the first day of testing, allowing the lidar team time to explore different settings and firmware updates to improve system performance. The data confirmed the sensor’s capability in a challenging, vibration-heavy environment, producing usable maps. Preliminary review of the recorded sensor data shows excellent reconstruction of the hazard field terrain.
A Hazard Detection Lidar scan of a simulated hazard field at Kennedy Space Center (left) and a combined 3D map identifying roughness and slope hazards. NASA Beyond lunar applications, SPLICE technologies are being considered for use on Mars Sample Return, the Europa Lander, Commercial Lunar Payload Services flights, and Gateway. The DLC design is also being evaluated for potential avionics upgrades on Artemis systems.
Additionally, SPLICE is supporting software tests for the Advancement of Geometric Methods for Active Terrain Relative Navigation (ATRN) Center Innovation Fund project, which is also part of Johnson’s Aeroscience and Flight Mechanics Division. The ATRN is working to develop algorithms and software that can use data from any active sensor – one measuring signals that were reflected, refracted, or scattered by a body’s surface or its atmosphere – to accurately map terrain and provide absolute and relative location information. With this type of system in place, spacecraft will not need external lighting sources to find landing sites.
With additional suborbital flight tests planned through 2026, the SPLICE team is laying the groundwork for safer, more autonomous landings on the Moon, Mars, and beyond. As NASA prepares for its next era of exploration, SPLICE will be a key part of the agency’s evolving landing, guidance, and navigation capabilities.
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NASA researchers are sending three air quality monitors to the International Space Station to test them for potential future use on the Moon.Credit: NASA/Sara Lowthian-Hanna As NASA prepares to return to the Moon, studying astronaut health and safety is a top priority. Scientists monitor and analyze every part of the International Space Station crew’s daily life—down to the air they breathe. These studies are helping NASA prepare for long-term human exploration of the Moon and, eventually, Mars.
As part of this effort, NASA’s Glenn Research Center in Cleveland is sending three air quality monitors to the space station to test them for potential future use on the Moon. The monitors are slated to launch on Monday, April 21, aboard the 32nd SpaceX commercial resupply services mission for NASA.
Like our homes here on Earth, the space station gets dusty from skin flakes, clothing fibers, and personal care products like deodorant. Because the station operates in microgravity, particles do not have an opportunity to settle and instead remain floating in the air. Filters aboard the orbiting laboratory collect these particles to ensure the air remains safe and breathable.
Astronauts will face another air quality risk when they work and live on the Moon—lunar dust.
“From Apollo, we know lunar dust can cause irritation when breathed into the lungs,” said Claire Fortenberry, principal investigator, Exploration Aerosol Monitors project, NASA Glenn. “Earth has weather to naturally smooth dust particles down, but there is no atmosphere on the Moon, so lunar dust particles are sharper and craggier than Earth dust. Lunar dust could potentially impact crew health and damage hardware.”
Future space stations and lunar habitats will need monitors capable of measuring lunar dust to ensure air filtration systems are functioning properly. Fortenberry and her team selected commercially available monitors for flight and ground demonstration to evaluate their performance in a spacecraft environment, with the goal of providing a dust monitor for future exploration systems.
NASA Glenn Research Center’s Claire Fortenberry holds a dust sample collected from International Space Station air filters.Credit: NASA/Sara Lowthian-Hanna Glenn is sending three commercial monitors to the space station to test onboard air quality for seven months. All three monitors are small: no bigger than a shoe box. Each one measures a specific property that provides a snapshot of the air quality aboard the station. Researchers will analyze the monitors based on weight, functionality, and ability to accurately measure and identify small concentrations of particles in the air.
The research team will receive data from the space station every two weeks. While those monitors are orbiting Earth, Fortenberry will have three matching monitors at Glenn. Engineers will compare functionality and results from the monitors used in space to those on the ground to verify they are working as expected in microgravity. Additional ground testing will involve dust simulants and smoke.
Air quality monitors like the ones NASA is testing also have Earth-based applications. The monitors are used to investigate smoke plumes from wildfires, haze from urban pollution, indoor pollution from activities like cooking and cleaning, and how virus-containing droplets spread within an enclosed space.
Results from the investigation will help NASA evaluate which monitors could accompany astronauts to the Moon and eventually Mars. NASA will allow the manufacturers to review results and ensure the monitors work as efficiently and effectively as possible. Testing aboard the space station could help companies investigate pollution problems here on Earth and pave the way for future missions to the Red Planet.
NASA Glenn Research Center’s Claire Fortenberry demonstrates how space aerosol monitors analyze the quality of the air.Credit: NASA/Sara Lowthian-Hanna “Going to the Moon gives us a chance to monitor for planetary dust and the lunar environment,” Fortenberry said. “We can then apply what we learn from lunar exploration to predict how humans can safely explore Mars.”
NASA commercial resupply missions to the International Space Station deliver scientific investigations in the areas of biology and biotechnology, Earth and space science, physical sciences, and technology development and demonstrations. Cargo resupply from U.S. companies ensures a national capability to deliver scientific research to the space station, significantly increasing NASA’s ability to conduct new investigations aboard humanity’s laboratory in space.
Learn more about NASA and SpaceX’s 32nd commercial resupply mission to the space station:
https://www.nasa.gov/nasas-spacex-crs-32/
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The Global Learning and Observations to Benefit the Environment (GLOBE) Program is calling on volunteers of all ages to help students and citizen scientists document seasonal change through leaf color and land cover. The data collection event will support students across North America, Latin America, Central America, and Europe, who are working together to document the seasonal changes taking place from September through December – see Figure. The observations will also provide vital data for GLOBE students creating student research projects for the GLOBE 2025 International Virtual Science Symposium (IVSS). The project is part of GLOBE’s Intensive Observation Period (IOP), which collects data during a focused period to assess how climate change is unfolding in different regions of the world.
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This is a test article in the live site I added this image
/wp-content/plugins/nasa-blocks/assets/images/media/media-example-01.jpgThis landscape of “mountains” and “valleys” speckled with glittering stars is actually the edge of a nearby, young, star-forming region called NGC 3324 in the Carina Nebula. Captured in infrared light by NASA’s new James Webb Space Telescope, this image reveals for the first time previously invisible areas of star birth.NASA, ESA, CSA, and STScIView the full article
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