SPACE/COSMOS
ESO observations help almost fully rule out 2024 YR4 asteroid impact
image:
Image of the asteroid 2024 YR4 taken by ESO’s Very Large Telescope (VLT). It shows a frame of the asteroid’s path through the night sky in January 2025, observed at infrared wavelengths with the HAWK-I instrument. These early observations contributed to increasing the odds of an impact on 22 December 2032 above 1%. However, thanks to newer data the odds have dropped to nearly zero.
view moreCredit: ESO/O. Hainaut
New observations of 2024 YR4 conducted with the European Southern Observatory’s Very Large Telescope (ESO’s VLT) and facilities around the world have all but ruled out an impact of the asteroid with our planet. The asteroid has been closely monitored in the past couple of months as its odds of impacting Earth in 2032 rose to around 3%, the highest impact probability ever reached for a sizable asteroid. After the latest observations, the odds of impact dropped to nearly zero.
The asteroid 2024 YR4, estimated to be about 40 to 90 metres in diameter, was discovered in late December last year on an orbit that could cause it to collide with Earth on 22 December 2032. Because of its size and likelihood of impact, the asteroid quickly rose to the top of the European Space Agency’s (ESA) risk list, a catalogue of all space rocks with any chance of impacting Earth.
ESO’s VLT was used to observe 2024 YR4 in mid-January, giving astronomers the crucial data they needed to more precisely calculate its orbit. Combined with data from other observatories, the very precise measurements from the VLT improved our knowledge of the asteroid's orbit, leading to an impact probability exceeding 1% — a key threshold to trigger disaster mitigation. More observations were triggered and the International Asteroid Warning Network issued a potential asteroid impact notification, alerting planetary defence groups, including the Space Mission Planning Advisory Group, about the possible impact.
With multiple telescopes around the world observing the asteroid, and astronomers modelling its orbit, the impact probability rose to around 3% on 18 February, the highest impact probability ever recorded for an asteroid larger than 30 metres. However, just the next day, new observations made with ESO’s VLT cut the impact risk in half.
This rise and fall of the asteroid’s impact probability follows an expected and understood pattern. To know where the asteroid will be in 2032, astronomers extrapolate from the small bit of the orbit measured thus far. ESO Astronomer Olivier Hainaut makes an analogy: “Because of the uncertainties, the orbit of the asteroid is like the beam of a flashlight: getting broader and broader and fuzzier in the distance. As we observe more, the beam becomes sharper and narrower. Earth was getting more illuminated by this beam: the probability of impact increased.”
The new VLT observations, together with data from other observatories, have allowed astronomers to constrain the orbit enough to all but rule out an impact with Earth in 2032. “The narrower beam is now moving away from Earth,” Hainaut says. At the time of writing, the impact probability reported by ESA’s Near-Earth Objects Coordination Centre is around 0.001% and the asteroid no longer tops ESA’s risk list.
As 2024 YR4 is moving away from Earth, it has become increasingly faint and difficult to observe it with all but the largest telescopes. ESO’s VLT has been instrumental in observations of this asteroid because of its mirror size and superb sensitivity, as well as the excellent dark skies at ESO’s Paranal Observatory in Chile, where the telescope is located. This makes it ideal to track faint objects such as 2024 YR4 and other potentially dangerous asteroids.
Unfortunately, the same Paranal's pristine dark skies that made these crucial measurements possible are currently under threat by the industrial megaproject INNA by AES Andes, a subsidiary of the US power company AES Corporation. The project is planned to cover an area similar in size to that of a small city and be located, at the closest point, about 11 km from the VLT. Due to its size and proximity, INNA would have devastating effects on the quality of the skies at Paranal, especially due to light pollution from its industrial facilities. With a brighter sky, telescopes like the VLT will lose their ability to detect some of the faintest cosmic targets.
Hainaut warns: “With that brighter sky, the VLT would lose the faint 2024 YR4 about one month earlier, which would make a huge difference in our capability to predict an impact, and prepare mitigation measures to protect Earth”.
More information
The observations were obtained in the context of the collaboration between ESA and ESO in contribution to the International Asteroid Warning Network. The team is composed of Olivier R. Hainaut (ESO), Marco Micheli (ESA NEO Coordination Centre), Bruno Leibundgut (ESO), Andrew Williams (formerly ESO, now ESA), Detlef Koschny (Technical University Munich, Germany), Luca Conversi (ESA). For the 2024 YR4 observations, they were joined by Maxime Devogele (ESA), Julia de Leon (Instituto de Astrofisica de Canarias, Spain) and Nicholas Moskovitz (Lowell Observatory, United States). FORS2 and HAWK-I were the VLT instruments used.
The European Southern Observatory (ESO) enables scientists worldwide to discover the secrets of the Universe for the benefit of all. We design, build and operate world-class observatories on the ground — which astronomers use to tackle exciting questions and spread the fascination of astronomy — and promote international collaboration for astronomy. Established as an intergovernmental organisation in 1962, today ESO is supported by 16 Member States (Austria, Belgium, Czechia, Denmark, France, Finland, Germany, Ireland, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom), along with the host state of Chile and with Australia as a Strategic Partner. ESO’s headquarters and its visitor centre and planetarium, the ESO Supernova, are located close to Munich in Germany, while the Chilean Atacama Desert, a marvellous place with unique conditions to observe the sky, hosts our telescopes. ESO operates three observing sites: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope and its Very Large Telescope Interferometer, as well as survey telescopes such as VISTA. Also at Paranal ESO will host and operate the Cherenkov Telescope Array South, the world’s largest and most sensitive gamma-ray observatory. Together with international partners, ESO operates ALMA on Chajnantor, a facility that observes the skies in the millimetre and submillimetre range. At Cerro Armazones, near Paranal, we are building “the world’s biggest eye on the sky” — ESO’s Extremely Large Telescope. From our offices in Santiago, Chile we support our operations in the country and engage with Chilean partners and society.
Links
The galactic journey of our solar system
Our sun and its planets crossed the Radcliffe Wave in the well-known Orion complex
University of Vienna
image:
Fig.1: Artistic representation of the Milky Way. The position of the Solar System is pointed by a white row.
view moreCredit: NASA/JPL-Caltech/ESO/R. Hurt
An international research team led by the University of Vienna has discovered that the Solar System traversed the Orion star-forming complex, a component of the Radcliffe Wave galactic structure, approximately 14 million years ago. This journey through a dense region of space could have compressed the heliosphere, the protective bubble surrounding our solar system, and increased the influx of interstellar dust, potentially influencing Earth's climate and leaving traces in geological records. The findings, published in Astronomy & Astrophysics, offer a fascinating interdisciplinary link between astrophysics, paleoclimatology, and geology.
The Solar System's journey around the Milky Way's center takes it through varying galactic environments. "Imagine it like a ship sailing through varying conditions at sea," explains Efrem Maconi, lead author and doctoral student at the University of Vienna. "Our Sun encountered a region of higher gas density as it passed through the Radcliffe Wave in the Orion constellation."
Using data from the European Space Agency's (ESA) Gaia mission and spectroscopic observations, the team pinpointed the Solar System's passage through the Radcliffe Wave in the Orion region about 14 million years ago. "This discovery builds upon our previous work identifying the Radcliffe Wave," says João Alves, professor of astrophysics at the University of Vienna and co-author of the study. The Radcliffe Wave is a vast, thin structure of interconnected star-forming regions, including the renowned Orion complex, which the Sun traversed, as established in this study.
"We passed through the Orion region as well-known star clusters like NGC 1977, NGC 1980, and NGC 1981 were forming," Alves notes. "This region is easily visible in the winter sky in the Northern Hemisphere and summer in the Southern Hemisphere. Look for the Orion constellation and the Orion Nebula (Messier 42)—our solar system came from that direction!"
The increased dust from this galactic encounter could have had several effects. It may have penetrated the Earth's atmosphere, potentially leaving traces of radioactive elements from supernovae in geological records. "While current technology may not be sensitive enough to detect these traces, future detectors could make it possible," Alves suggests.
The team's research indicates the Solar System's passage through the Orion region occurred between approximately 18.2 and 11.5 million years ago, with the most likely time between 14.8 and 12.4 million years ago. This timeframe aligns well with the Middle Miocene Climate Transition, a significant shift from a warm variable climate to a cooler climate, leading to the establishment of a continental-scale prototype Antarctic ice sheet configuration. While the study raises the possibility of a link between the past traverse of the solar system through its galactic neighborhood and Earth’s climate via interstellar dust, the authors emphasize that a causal connection requires further investigation.
Not comparable to the current human-made Climate Change
"While the underlying processes responsible for the Middle Miocene Climate Transition are not entirely identified, the available reconstructions suggest that a long-term decrease in the atmospheric greenhouse gas carbon dioxide concentration is the most likely explanation, although large uncertainties exist. However, our study highlights that interstellar dust related to the crossing of the Radcliffe Wave might have impacted Earth’s climate and potentially played a role during this climate transition. To alter the Earth’s climate the amount of extraterrestrial dust on Earth would need to be much bigger than what the data so far suggest," says Maconi. "Future research will explore the significance of this contribution. It’s crucial to note that this past climate transition and current climate change are not comparable since the Middle Miocene Climate Transition unfolded over timescales of several hundred thousand years. In contrast, the current global warming evolution is happening at an unprecedented rate over decades to centuries due to human activity."
This study is important because it adds a small puzzle piece to the recent history of the Solar System, helping to place it in the context of the Milky Way. "We are inhabitants of the Milky Way," says Alves, "The European Space Agency’s Gaia Mission has given us the means to trace our recent route in the Milky Way’s interstellar sea, allowing astronomers to compare notes with geologists and paleoclimatologists. It’s very exciting." In the future, the team led by João Alves plans to study in more detail the Galactic environment encountered by the Sun while sailing through our Galaxy.
Fig. 2: The Radcliffe wave. The clouds that comprise this structure are highlighted in red and superimposed on an artist's illustration of the Milky Way. The location of the Sun is highlighted by the yellow dot.
Credit
Alyssa A. Goodman/Harvard University
Fig. 4: The Orion belt.
Credit
Davide De Martin & the ESA/ESO/NASA Photoshop FITS Liberator
\Fig. 3: The Orion constellation. The main stars of this constellation are connected by straight blue lines and some of them are labelled by their name. The Orion Nebula (M 42) is identified by the red square. The image is a screenshot from Stellarium.
Credit
Created by Stellarium (GNU), Edited by Efrem Maconi
Created by Stellarium (GNU), Edited by Efrem Maconi
Journal
Astronomy and Astrophysics
Article Title
The Solar System’s Passage through the Radcliffe Wave during the Middle Miocene.
Today's forecast: Partially cloudy skies on an "ultra-hot Neptune"
University of Montreal
image:
Illustration of LTT 9779 b, the only known ultra-hot Neptune. This planet orbits so close to its star that its atmosphere is scorching hot, glowing from its own heat while also reflecting starlight. Because it is tidally locked - always showing the same side to its star - one half is permanently in daylight while the other remains in darkness. New JWST observations with NIRISS reveal a dynamic atmosphere: powerful winds sweep around the planet, shaping mineral clouds as they condense into a bright, white arc on the slightly cooler western side of the dayside. As these clouds move eastward, they evaporate under the intense heat, leaving the eastern dayside with clear skies.
view moreCredit: Benoit Gougeon, Université de Montréal
The exotic atmosphere of LTT 9779 b, a rare “ultra-hot Neptune," is coming to light thanks to observations via the James Webb Space Telescope led by Louis-Philippe Coulombe, a graduate student at Université de Montréal's Trottier Institute for Research on Exoplanets (IREx).
Published today in Nature Astronomy, the observations by Coulombe and his team, offer new insights into the extreme weather patterns and atmospheric properties of this fascinating exoplanet.
Orbiting its host star in less than a day, LTT 9779 b is subjected to searing temperatures reaching almost 2,000°C on its dayside. The planet is tidally locked (similar to Earth’s Moon), meaning one side constantly faces its star while the other remains in perpetual darkness.
Despite these extremes, Coulombe’s team discovered that the exoplanet’s dayside hosts reflective clouds on its cooler western hemisphere, creating a striking contrast to the hotter eastern side.
“This planet provides a unique laboratory to understand how clouds and the transport of heat interact in the atmospheres of highly irradiated worlds,” said Coulombe.
Asymmetry on the dayside
Using the James Webb Space Telescope (JWST), his team uncovered an asymmetry in the planet’s dayside reflectivity. They propose that the uneven distribution of heat and clouds is driven by powerful eastward winds that transport heat around the planet.
These findings help refine models describing how heat is transported across a planet and cloud formation in exoplanet atmospheres, thereby also bridging the gap between theory and observation.
The research team studied the atmosphere in detail by analyzing both the heat emitted by the
planet and the light it reflects from its star. To create a clearer picture, they observed the planet at multiple positions in its orbit and analysed its properties at each phase individually.
They discovered clouds made of materials like silicate minerals, which form on the slightly cooler western side of the planet’s dayside. These reflective clouds help explain why this planet is so bright at visible wavelengths, bouncing back much of the star’s light.
By combining this reflected light with heat emissions, the team was able to create a detailed model of the planet’s atmosphere. Their findings reveal a delicate balance between intense heat from the star and the planet’s ability to redistribute energy.
The study also detected water vapour in the atmosphere, providing important clues about the planet's composition and the processes that govern its extreme environment.
"By modeling LTT 9779 b’s atmosphere in detail, we’re starting to unlock the processes driving its alien weather patterns," said Coulombe’s research advisor Björn Benneke, an UdeM professor of astronomy and co-author of the study.
An incredibly powerful telescope
With this study, the JWST has once again demonstrated its incredible power, allowing scientists to study the atmosphere of LTT 9779 b in unprecedented detail.
Its Canadian instrument, the Near Infrared Imager and Slitless Spectrograph (NIRISS), was used to observe the planet for nearly 22 hours. The data captured the planet’s full orbit around its star, including two secondary eclipses (when the planet passes behind its star) and a primary transit (when the planet passes in front of its star).
For an exoplanet like LTT 9779 b, which is tidally locked to its star, the amount and type of light that's observed changes as the planet rotates, showing us different parts of its surface. The dayside reflects and emits more light due to intense heating, while the cooler nightside emits less light. By capturing spectra at various phases, researchers can map out variations in temperature, composition and even cloud coverage across the planet's surface.
Michael Radica, a former PhD student at UdeM and now a postdoctoral researcher at the University of Chicago, was the second author of this study. Earlier this year, he published
a detailed analysis of the planet’s light spectrum during transit. “It’s remarkable that both types of analyses paint such a clear and consistent picture of the planet’s atmosphere,” he noted.
The research was conducted as part of the NEAT (NIRISS Exploration of Atmospheric Diversity of Transiting Exoplanets) Guaranteed Time Observation program, led by IREx’s David Lafrenière, an UdeM astrophysic professor.
The study highlights the importance of JWST’s ability to observe exoplanets across a wide wavelength range, allowing scientists to disentangle the contributions of reflected light and thermal emission, he said.
“This is exactly the kind of groundbreaking work JWST was designed to enable.”
Remarkably rare hot Neptunes
LTT 9779 b resides in the “hot Neptune desert,” where exceptionally few such planets are known to exist. While giant planets orbiting very close to their host stars—often called "hot Jupiters"—are commonly detected using current exoplanet-finding methods, ultra-hot Neptunes like LTT 9779 b remain remarkably rare.
"Finding a planet of this size so close to its host star is like finding a snowball that hasn’t melted in a fire,” said Coulombe. “It’s a testament to the diversity of planetary systems and offers a window into how planets evolve under extreme conditions."
This rare planetary system continues to challenge scientists’ understanding of how planets form, migrate, and endure in the face of unrelenting stellar forces. LTT 9779 b's reflective clouds and high metallicity may shed light on how atmospheres evolve in extreme environments, too.
LTT 9779 b is a remarkable laboratory for exploring these questions, offering insights into the broader processes that shape the architecture of planetary systems across the galaxy, said Coulombe.
“These findings give us a new lens for understanding atmospheric dynamics on smaller gas giants. This is just the beginning of what JWST will reveal about these fascinating worlds.”
Journal
Nature Astronomy
Subject of Research
Not applicable
Article Title
Highly-reflective clouds on the western dayside of an exo-Neptune identified with phase-resolved reflected-light and thermal-emission spectroscopy
Article Publication Date
25-Feb-2025
JWST provides insights into rare ultra-hot Neptune LTT 9779 b
University of Oxford
A team of international researchers including Dr Jake Taylor from the Department of Physics at the University of Oxford, has used the James Webb Space Telescope (JWST) to explore the exotic atmosphere of LTT 9779 b, a rare ‘ultra-hot Neptune’. The results have been published today (25 February) in a compelling new study in Nature Astronomy.
The study offers new insights into the extreme weather patterns and atmospheric properties of this fascinating exoplanet, LTT 9779 b, that resides in the so-called hot Neptune desert, a category of planets where exceptionally few are known to exist. While giant planets orbiting very close to their host stars – often called hot Jupiters – are commonly detected using current exoplanet-finding methods, ultra-hot Neptunes like LTT 9779 b remain remarkably rare.
‘Finding a planet of this size so close to its host star is like finding a snowball that hasn’t melted in a fire,’ says graduate student Louis-Philippe Coulombe from the Université de Montréal's Trottier Institute for Research on Exoplanets (IREx) who led the study. ‘It’s a testament to the diversity of planetary systems and offers a window into how planets evolve under extreme conditions.’
A unique laboratory for alien weather
Orbiting its host star in less than a day, LTT 9779 b is subjected to searing temperatures reaching almost 2,000°C on its dayside. The planet is tidally locked (similar to Earth’s Moon), meaning one side constantly faces its star while the other remains in perpetual darkness. Despite such extremes, the team discovered that the planet’s dayside hosts reflective clouds on its cooler western hemisphere, creating a striking contrast to the hotter eastern side. ‘This planet provides a unique laboratory to understand how clouds and the transport of heat interact in the atmospheres of highly irradiated worlds,’ says Coulombe.
Dr Taylor from the University of Oxford worked alongside Coulombe in analysing the data. The pair had previously performed an initial atmospheric analysis of the planet’s spectrum, the results of which were published in The Astrophysical Journal Letters in 2024: ‘Our original study of the transmission spectrum hinted at the need for high altitude clouds to explain the observations; our latest study confirms the existence of these clouds,’ he explains.
The team’s analysis, conducted using JWST as part of the NEAT (NIRISS Exploration of Atmospheric Diversity of Transiting Exoplanets) Guaranteed Time Observation programme, uncovered an asymmetry in the planet’s dayside reflectivity. The team proposed that the uneven distribution of heat and clouds is driven by powerful winds that transport heat around the planet. These findings help refine models describing how heat is transported across a planet and cloud formation in exoplanet atmospheres, helping bridge the gap between theory and observation.
Mapping the atmosphere of an ultra-hot Neptune
The research team studied the atmosphere in detail by analysing both the heat emitted by the planet and the light it reflects from its star. To create a clearer picture, they observed the planet at multiple positions in its orbit and analysed its properties at each phase individually. They discovered clouds made of materials like silicate minerals, which form on the slightly cooler western side of the planet’s dayside. These reflective clouds help explain why this planet is so bright at visible wavelengths, bouncing back much of the star’s light.
By combining this reflected light with heat emissions, the team was able to create a detailed model of the planet’s atmosphere. Their findings reveal a delicate balance between intense heat from the star and the planet’s ability to redistribute energy. The study also detected water vapour in the atmosphere, providing important clues about the planet's composition and the processes that govern its extreme environment.
‘By modelling LTT 9779 b’s atmosphere in detail, we’re starting to unlock the processes driving its alien weather patterns,’ explains Professor Björn Benneke, a co-author of the study and Coulombe’s research advisor.
Implications for exoplanet science
This rare planetary system continues to challenge scientists’ understanding of how planets form, migrate, and endure in the face of unrelenting stellar forces. The planet’s reflective clouds and high metallicity may shed light on how atmospheres evolve in extreme environments. LTT 9779 b is a remarkable laboratory for exploring these questions, offering insights into the broader processes that shape the architecture of planetary systems across the galaxy.
‘These findings give us a new lens for understanding atmospheric dynamics on smaller gas giants,’ says Coulombe. ‘This is just the beginning of what JWST will reveal about these fascinating worlds.’
Other instruments are also being used to comprehensively study these rare planetary systems: ‘We haven’t finished piecing together the information about this planet yet,’ concludes Dr Taylor. ‘We are currently using observations from the Hubble Space Telescope and the Very Large Telescope to study the dayside cloud structure in more detail to learn as much as possible.’
Notes for editors
For media inquiries, contact Dr Caroline Wood: caroline.wood@admin.ox.ac.uk
This research is part of the NEAT Guaranteed Time Observations program, led by Professor David Lafrenière.
The full article, titled Highly-reflective clouds on the western dayside of an exo-Neptune identified with phase-resolved reflected-light and thermal-emission spectroscopy, has been published in Nature Astronomy, at https://www.nature.com/articles/s41550-025-02488-9
The authors acknowledge financial support from the Canadian Space Agency for this study.
About the University of Oxford
Oxford University has been placed number 1 in the Times Higher Education World University Rankings for the ninth year running, and number 3 in the QS World Rankings 2024. At the heart of this success are the twin-pillars of our ground-breaking research and innovation and our distinctive educational offer.
Oxford is world-famous for research and teaching excellence and home to some of the most talented people from across the globe. Our work helps the lives of millions, solving real-world problems through a huge network of partnerships and collaborations. The breadth and interdisciplinary nature of our research alongside our personalised approach to teaching sparks imaginative and inventive insights and solutions.
Through its research commercialisation arm, Oxford University Innovation, Oxford is the highest university patent filer in the UK and is ranked first in the UK for university spinouts, having created more than 300 new companies since 1988. Over a third of these companies have been created in the past five years. The university is a catalyst for prosperity in Oxfordshire and the United Kingdom, contributing £15.7 billion to the UK economy in 2018/19, and supports more than 28,000 full time jobs.
Journal
Nature Astronomy
Article Title
Highly-reflective clouds on the western dayside of an exo-Neptune identified with phase-resolved reflected-light and thermal-emission spectroscopy
Article Publication Date
25-Feb-2025
Lunar Trailblazer blasts off to map water on the Moon
University of Oxford
image:
Infographic of Lunar Trailblazer Data Collection. Credit: Filo Merid for Lunar Trailblazer
view moreCredit: Filo Merid for Lunar Trailblazer
On Wednesday 26 February, a thermal imaging camera built by researchers at the University of Oxford’s Department of Physics will blast off to the Moon as part of NASA’s Lunar Trailblazer mission. This aims to map sources of water on the Moon to shed light on the lunar water cycle and to guide future robotic and human missions.
Once in orbit, the spacecraft – weighing 200kg and about the size of a washing machine- will map the surface temperature and composition of the lunar surface 12 times a day, at a resolution of 50 metres. Using cutting-edge instruments, it will examine features including the permanently shadowed craters at the Moon's South Pole, which could contain significant quantities (potentially 600 million metric tons) of water ice. This could be used in various ways, from purifying it as drinking water to processing it for fuel and breathable oxygen for future human Moon landings.
One of the two principal instruments, the Lunar Thermal Mapper (LTM), was constructed by researchers in the Planetary Experiments Group at the University of Oxford’s Department of Physics. This will measure the surface temperature and the various minerals that make up the lunar landscape, to help confirm the presence and location of water. The instrument will work in tandem with NASA/JPL’s High-resolution Volatiles and Minerals Moon Mapper (HVM3) to produce the most detailed maps of water on the Moon's surface to date. (Further details on how the instruments work below)
Lunar Trailblazer was a NASA’s Small Innovative Missions for Planetary Exploration (SIMPLEx) selection in 2019, which provides opportunities for low-cost science spacecraft to ride-share with selected primary missions. The spacecraft will launch as a secondary payload on a planned lunar lander mission led by Intuitive Machines, effectively hitchhiking on the larger spacecraft, which will attempt a soft landing on the Moon.
Since the spacecraft has a relatively small engine, its planned trajectory will use the gravity of the Sun, Earth, and Moon to guide it to the final orbit — a technique called low-energy transfer. The momentum provided by the rocket booster will propel the spacecraft past the Moon and into deep space before it is pulled back by gravity. The spacecraft will then use small thruster bursts to slowly correct its orbit until it is about 60 miles (100 kilometers) above the Moon’s surface. In all, Lunar Trailblazer should take between four and seven months to arrive in its final orbit.
The LTM was constructed by the Planetary Experiments Group at the University of Oxford’s Department of Physics, with £3.1 million funding from the UK Space Agency and the Department for Science, Innovation and Technology (DSIT). For the group, building the LTM is the latest achievement in a 50-year history of developing components for spaceflight and infrared thermal mapping cameras, including for missions to Mars, Saturn, and the Moon. With the LTM’s components being produced by various UK academic institutes and companies (details below), this collective effort highlights the nation's leading role in space exploration and scientific research.
Professor Neil Bowles, Instrument Scientist for LTM at the University of Oxford’s Department of Physics, said:
“The Lunar Thermal Mapper was designed, built and tested here in Oxford and the launch is an important moment for the whole of our team. The measurements of temperature will help confirm the presence of the water signal in HVM3’s measurements and the two instruments will work together to map the composition of the Moon, showing us details that have only been hinted at previously.”
The mission could also reveal why the Moon has water in the first place. Possible reasons include comets and ‘wet asteroids’ crashing into the Moon; ancient volcanic eruptions disgorging water vapor from the Moon’s interior; or hydrogen within the solar wind combining with oxygen on the Moon. Lunar Trailblazer's findings will shed light on which hypothesis is more likely.
Lauren Taylor, Major Projects Lead from The UK Space Agency said:
"The UK Space Agency is thrilled to be a part of NASA's Lunar Trailblazer mission. Our work with the University of Oxford to develop the Lunar Thermal Mapper showcases the UK's leading role in space exploration and scientific research.
“This mission will provide invaluable data on the Moon's water resources, supporting future human missions and enhancing our understanding of the lunar environment.”
Notes to editors
For media requests and interviews, contact Caroline Wood: caroline.wood@admin.ox.ac.uk
Many images related to the mission are available here (must be credited): https://trailblazer.caltech.edu/gallery.html
https://flickr.com/photos/lockheedmartin/albums/72177720305810321/with/52673223964
Further information can be found on the Lunar Trailblazer website: https://trailblazer.caltech.edu/
To receive the press pack for the mission, with further graphics and diagrams, contact Caroline Wood: caroline.wood@admin.ox.ac.uk
The most up-to-date information about Lunar Trailblazer mission media events and where to watch them is available at nasa.gov/multimedia/nasatv/schedule.html News briefings and launch commentary will be streamed on NASA TV, NASA.gov/live, and YouTube.com/NASA. On-demand recordings will also be available on YouTube after the live events have finished.
Further detail on how the Lunar Thermal Mapper works:
The two instruments on the Lunar Trailblazer spacecraft - the Lunar Thermal Mapper (LTM) and High-resolution Volatiles and Minerals Moon Mapper (HVM3) will work in tandem to generate high-resolution maps of the Moon’s water to help determine the Moon’s water cycle.
The Oxford-built LTM will use four broadband infrared channels to measure the temperature of the lunar surface ranging from approximately -163°C to 127°C. The instrument will also use eleven narrow infrared channels to map small variations in the composition of silicate minerals that make up the rocks and soils of the Moon’s surface. This will provide more information about what the lunar surface is made of and where water may potentially be found.
Meanwhile, the HVM3 (built by NASA’s Jet Propulsion Laboratory and funded by NASA) will detect and map the form, abundance, and locations of water over the lunar landscape by measuring spectral fingerprints (wavelengths of reflected sunlight). The temperature of the surface being measured affects the apparent strength of the absorption signal of water, therefore the HVM3 spectral data will be calibrated using the temperature measurements recorded at the same time by the LTM.
By mapping the Moon day and night, Lunar Trailblazer will be able to detect whether the amount of water changes on this airless body, for instance, by transforming into a gas as the surface heats up, or accumulating like frost in the shadowed regions as the surface cools down. The mission will help answer key questions such as whether water molecules might be locked up inside lunar rock, or if the permanently shadowed craters at the lunar poles hold significant quantities of water ice.
The UK’s contribution to NASA’s Lunar Trailblazer mission:
The Lunar Trailblazer mission is led by Principal Investigator Professor Bethany Ehlmann at the California Institute of Technology (Caltech) and managed by NASA’s Jet Propulsion Laboratory in Southern California. The LTM was designed, built, and tested by the Department of Physics, University of Oxford, with optics manufactured by Durham University’s Centre for Advanced Instrumentation and far infrared filters supplied by the University of Cardiff and specialist manufacturers based across the UK. Support for electronics and software design early in the project was provided by RAL Space.
NASA’s Lunar Trailblazer sits in a clean room at Lockheed Martin Space in Littleton, Colorado, shortly after being integrated with its second and final science instrument, the Lunar Thermal Mapper. Green tape on the spacecraft will be removed before launch.
Credit: Lockheed Martin for Lunar Trailblazer
Credit
Lockheed Martin for Lunar Trailblazer
NASA's Lunar Trailblazer sits on its rotation fixture after being fueled and prior to being installed to the EELV Secondary Payload Adapter (ESPA) ring at SpaceX's Payload Processing Facility in NASA's Kennedy Space Center in Florida in early February 2025. The ESPA ring is an adaptor used for launching secondary payloads on launch vehicles. The mission's two science instruments are visible. Here, the spacecraft is mounted horizontally, in its launch configuration, to the ESPA ring. Credit: SpaceX
Credit
SpaceX
SwRI-led PUNCH spacecraft poised for launch into polar orbit
NASA’s PUNCH mission to integrate solar corona activity with origins of the solar wind
image:
Four suitcase-sized spacecraft, designed and built by Southwest Research Institute, passed all final evaluations and are now loaded into the faring awaiting launch into low Earth orbit no earlier than Feb. 28. NASA’s PUNCH mission is designed to provide a unified, integrated image of the solar corona and the nascent solar wind for the first time.
view moreCredit: Southwest Research Institute
SAN ANTONIO — February 25, 2025 —Four small suitcase-sized spacecraft, designed and built by Southwest Research Institute headquartered in San Antonio, are poised to launch from Vandenberg Space Force Base in California no earlier than Feb. 28. NASA’s Polarimeter to Unify the Corona and Heliosphere, or PUNCH, spacecraft is sharing a ride to space with the Spectro-Photometer for the History of the Universe, Epoch of Reionization and Ices Explorer (SPHEREx) observatory.
“The PUNCH mission will study the solar corona, the Sun’s outer atmosphere, and the solar wind that fills and defines our solar system as a unified, integrated system,” said PUNCH Principal Investigator Dr. Craig DeForest of SwRI’s Solar System Science and Exploration Division located in Boulder, Colo. “This has not been possible before because we used different kinds of instruments to characterize these regions. PUNCH will integrate our understanding of the role the corona plays in heating and accelerating the solar wind, which washes across the Earth and the rest of the planets in our solar system.”
Following launch, the PUNCH constellation of satellites will spread out in a low-Earth orbit along the day-night line, so the spacecraft will remain in sunlight with a clear view in all directions.
“To get the data we need, we had to create an instrument as large as the Earth,” DeForest said. “That wasn’t possible, so we used four small spacecraft, synchronized and spread around the Earth, to create a virtual instrument 8,000 miles wide, imaging a quarter of the sky, centered on the Sun.”
One satellite carries a coronagraph, the Narrow Field Imager developed by the U.S. Naval Research Laboratory, that images the Sun’s corona continuously. The other three carry SwRI-developed Wide Field Imagers, designed to view the very faint outermost portion of the solar corona and the solar wind itself.
“PUNCH is going to make the invisible visible,” DeForest said. “Deep baffles in our wide-field imagers reduce direct sunlight by over 16 orders of magnitude or a factor of 10 million billion — the ratio between the mass of a human and the mass of a cold virus. Then state-of-the-art processing on the ground removes the background starfield, over 99% of the light in each image, to reveal the extremely faint glimmer of the solar wind.”
Each spacecraft includes a camera, developed by RAL Space, to collect three raw images, through three different polarizing filters, every four minutes. In addition, each spacecraft will produce a clear unpolarized image every eight minutes, for calibration purposes. This new perspective will allow scientists to discern the exact trajectory and speed of coronal mass ejections as they move through the inner solar system, improving on current instruments that only measure the corona itself and cannot measure motion in three dimensions.
“While PUNCH is a research mission, we will be able to track space storms, or coronal mass ejections, in three dimensions as they approach the Earth — this is critical to forecasting space weather and how it might affect us as a space-faring society,” DeForest said. “We hope PUNCH will help revolutionize space weather forecasting in the same way that geosynchronous satellites revolutionized weather forecasting on Earth.”
NASA’s Small Explorers (SMEX) program provides frequent flight opportunities for world-class scientific investigations from space using innovative, efficient approaches within the heliophysics and astrophysics science areas. In addition to leading the PUNCH science mission, SwRI will operate the four spacecraft. The PUNCH team includes the U.S. Naval Research Laboratory, which built the Narrow Field Imager, and RAL Space in Oxfordshire, England, which provided detector systems for the four visible-light cameras.
To view a video about the mission, see: https://youtu.be/3BL18jyKeOI.
The four PUNCH satellites designed and built by SwRI will provide a 90-degree portrait of the sky centered on the Sun, as illustrated here. The Narrow Field Imager aboard one satellite is a coronagraph that blocks out the brightest light from the Sun to show the fainter corona. The three SwRI-developed Wide Field Imagers use baffling and ground processing technology to show the faint traces of the outer corona and the solar wind itself, 1,000 times fainter than the Milky Way galaxy.
NASA’s PUNCH mission will use four suitcase-sized satellites, designed and built by SwRI, spread out around Earth and synchronized to serve as a single “virtual” instrument 8,000 miles across. Illustration is not to scale.
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Southwest Research Institute
For more information, visit https://www.swri.org/markets/earth-space/space-research-technology/space-science/heliophysics.
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