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By NASA
Explore This Section Overview Science Science Findings Juno’s Orbits Spacecraft People Stories Multimedia JunoCam Images Jupiter hosts the brightest and most spectacular auroras in the Solar System. Near its poles, these shimmering lights offer a glimpse into how the planet interacts with the solar wind and moons swept by Jupiter’s magnetic field. Unlike Earth’s northern lights, the largest moons of Jupiter create their own auroral signatures in the planet’s atmosphere — a phenomenon that Earth’s Moon does not produce. These moon-induced auroras, known as “satellite footprints,” reveal how each moon interacts with its local space environment.
Juno capturing the marks on Jupiter of all four Galilean moons. The auroras related to each are labeled Io, Eur (for Europa), Gan (for Ganymede), and Cal (for Callisto). NASA/JPL-Caltech/SwRI/UVS team/MSSS/Gill/Jónsson/Perry/Hue/Rabia Before NASA’s Juno mission, three of Jupiter’s four largest moons, known as Galilean moons — Io, Europa, and Ganymede — were shown to produce these distinct auroral signatures. But Callisto, the most distant of the Galilean moons, remained a mystery. Despite multiple attempts using NASA’s Hubble Space Telescope, Callisto’s footprint had proven elusive, both because it is faint and because it most often lies atop the brighter main auroral oval, the region where auroras are displayed.
NASA’s Juno mission, orbiting Jupiter since 2016, offers unprecedented close-up views of these polar light shows. But to image Callisto’s footprint, the main auroral oval needs to move aside while the polar region is being imaged. And to bring to bear Juno’s arsenal of instruments studying fields and particles, the spacecraft’s trajectory must carry it across the magnetic field line linking Callisto and Jupiter.
These two events serendipitously occurred during Juno’s 22nd orbit of the giant planet, in September 2019, revealing Callisto’s auroral footprint and providing a sample of the particle population, electromagnetic waves, and magnetic fields associated with the interaction.
Jupiter’s magnetic field extends far beyond its major moons, carving out a vast region (magnetosphere) enveloped by, and buffeted by, the solar wind streaming from our Sun. Just as solar storms on Earth push the northern lights to more southern latitudes, Jupiter’s auroras are also affected by our Sun’s activity. In September 2019, a massive, high-density solar stream buffeted Jupiter’s magnetosphere, briefly revealing — as the auroral oval moved toward Jupiter’s equator — a faint but distinct signature associated with Callisto. This discovery finally confirms that all four Galilean moons leave their mark on Jupiter’s atmosphere, and that Callisto’s footprints are sustained much like those of its siblings, completing the family portrait of the Galilean moon auroral signatures.
An international team of scientists led by Jonas Rabia of the Institut de Recherche en Astrophysique et Planétologie (IRAP), CNRS, CNES, in Toulouse, France, published their paper on the discovery, “In situ and remote observations of the ultraviolet footprint of the moon Callisto by the Juno spacecraft,” in the journal Nature Communications on Sept. 1, 2025.
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Last Updated Sep 02, 2025 Related Terms
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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.
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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.
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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
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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
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By NASA
5 min read
Close-Up Views of NASA’s DART Impact to Inform Planetary Defense
Photos taken by the Italian LICIACube, short for the LICIA Cubesat for Imaging of Asteroids. These offer the closest, most detailed observations of NASA’s DART (Double Asteroid Redirection Test) impact aftermath to date. The photo on the left was taken roughly 2 minutes and 40 seconds after impact, as the satellite flew past the Didymos system. The photo on the right was taken 20 seconds later, as LICIACube was leaving the scene. The larger body, near the top of each image is Didymos. The smaller body in the lower half of each image is Dimorphos, enveloped by the cloud of rocky debris created by DART’s impact. NASA/ASI/University of Maryland On Sept. 11, 2022, engineers at a flight control center in Turin, Italy, sent a radio signal into deep space. Its destination was NASA’s DART (Double Asteroid Redirection Test) spacecraft flying toward an asteroid more than 5 million miles away.
The message prompted the spacecraft to execute a series of pre-programmed commands that caused a small, shoebox-sized satellite contributed by the Italian Space Agency (ASI), called LICIACube, to detach from DART.
Fifteen days later, when DART’s journey ended in an intentional head-on collision with near-Earth asteroid Dimorphos, LICIACube flew past the asteroid to snap a series of photos, providing researchers with the only on-site observations of the world’s first demonstration of an asteroid deflection.
After analyzing LICIACube’s images, NASA and ASI scientists report on Aug. 21 in the Planetary Science Journal that an estimated 35.3 million pounds (16 million kilograms) of dust and rocks spewed from the asteroid as a result of the crash, refining previous estimates that were based on data from ground and space-based observations.
While the debris shed from the asteroid amounted to less than 0.5% of its total mass, it was still 30,000 times greater than the mass of the spacecraft. The impact of the debris on Dimorphos’ trajectory was dramatic: shortly after the collision, the DART team determined that the flying rubble gave Dimorphos a shove several times stronger than the hit from the spacecraft itself.
“The plume of material released from the asteroid was like a short burst from a rocket engine,” said Ramin Lolachi, a research scientist who led the study from NASA’s Goddard Space Flight Center in Greenbelt, Maryland.
The important takeaway from the DART mission is that a small, lightweight spacecraft can dramatically alter the path of an asteroid of similar size and composition to Dimorphos, which is a “rubble-pile” asteroid — or a loose, porous collection of rocky material bound together weakly by gravity.
“We expect that a lot of near-Earth asteroids have a similar structure to Dimorphos,” said Dave Glenar, a planetary scientist at the University of Maryland, Baltimore County, who participated in the study. “So, this extra push from the debris plume is critical to consider when building future spacecraft to deflect asteroids from Earth.”
The tail of material that formed behind Dimorphos was prominent almost 12 days after the DART impact, giving the asteroid a comet-like appearance, as seen in this image captured by NASA’s Hubble Space Telescope in October 2022. Hubble’s observations were made from roughly 6.8 million miles away. NASA, ESA, STScI, Jian-Yang Li (PSI); Image Processing: Joseph DePasquale DART’s Star Witness
NASA chose Dimorphos, which poses no threat to Earth, as the mission target due to its relationship with another, larger asteroid named Didymos. Dimorphos orbits Didymos in a binary asteroid system, much like the Moon orbits Earth. Critically, the pair’s position relative to Earth allowed astronomers to measure the duration of the moonlet’s orbit before and after the collision.
Ground and space-based observations revealed that DART shortened Dimorphos’ orbit by 33 minutes. But these long-range observations, made from 6.8 million miles (10.9 million kilometers) away, were too distant to support a detailed study of the impact debris. That was LICIACube’s job.
After DART’s impact, LICIACube had just 60 seconds to make its most critical observations. Barreling past the asteroid at 15,000 miles (21,140 kilometers) per hour, the spacecraft took a snapshot of the debris roughly once every three seconds. Its closest image was taken just 53 miles (85.3 km) from Dimorphos’ surface.
The short distance between LICIACube and Dimorphos provided a unique advantage, allowing the cubesat to capture detailed images of the dusty debris from multiple angles.
The research team studied a series of 18 LICIAcube images. The first images in the sequence showed LICIACube’s head-on approach. From this angle, the plume was brightly illuminated by direct sunlight. As the spacecraft glided past the asteroid, its camera pivoted to keep the plume in view.
This animated series of images was taken by a camera aboard LICIACube 2 to 3 minutes after DART crashed into Dimorphos. As LICIACube made its way past the binary pair of asteroids Didymos, the larger one on top, and Dimorphos, the object at the bottom. The satellite’s viewing angle changed rapidly during its flyby of Dimorphos, allowing scientists o get a comprehensive view of the impact plume from a series of angles. ASI/University of Maryland/Tony Farnham/Nathan Marder As LICIACube looked back at the asteroid, sunlight filtered through the dense cloud of debris, and the plume’s brightness faded. This suggested the plume was made of mostly large particles — about a millimeter or more across — which reflect less light than tiny dust grains.
Since the innermost parts of the plume were so thick with debris that they were completely opaque, the scientists used models to estimate the number of particles that were hidden from view. Data from other rubble-pile asteroids, including pieces of Bennu delivered to Earth in 2023 by NASA’s OSIRIS-REx spacecraft, and laboratory experiments helped refine the estimate.
“We estimated that this hidden material accounted for almost 45% of the plume’s total mass,” said Timothy Stubbs, a planetary scientist at NASA Goddard who was involved with the study.
While DART showed that a high-speed collision with a spacecraft can change an asteroid’s trajectory, Stubbs and his colleagues note that different asteroid types, such as those made of stronger, more tightly packed material, might respond differently to a DART-like impact. “Every time we interact with an asteroid, we find something that surprises us, so there’s a lot more work to do,” said Stubbs. “But DART is a big step forward for planetary defense.”
The Johns Hopkins Applied Physics Laboratory in Laurel, Maryland, managed the DART mission and operated the spacecraft for NASA’s Planetary Defense Coordination Office as a project of the agency’s Planetary Missions Program Office.
By Nathan Marder, nathan.marder@nasa.gov
NASA’s Goddard Space Flight Center, Greenbelt, Md.
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Last Updated Aug 21, 2025 Related Terms
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By NASA
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Preparations for Next Moonwalk Simulations Underway (and Underwater)
The Artemis II Orion stage adapter, built at NASA’s Marshall Space Flight Center in Huntsville, Alabama. NASA Media are invited to NASA’s Marshall Space Flight Center in Huntsville, Alabama, at 2 p.m. CDT Thursday, Aug. 14 to view the final piece of space flight hardware for the agency’s SLS (Space Launch System) rocket for the Artemis II mission before it is delivered to NASA’s Kennedy Space Center in Florida. All other elements of the SLS rocket for Artemis II are stacked on mobile launcher 1 in the Vehicle Assembly Building at Kennedy. Artemis II, NASA’s first mission with crew aboard the SLS rocket and Orion spacecraft, is currently scheduled for a 10-day trip around the Moon no later than April 2026.
The Orion stage adapter, built by NASA Marshall, connects the SLS rocket’s interim cryogenic propulsion stage to NASA’s Orion spacecraft. The small ring structure is the topmost portion of the SLS rocket. The adapter will also carry small payloads, called CubeSats, to deep space.
Media will have the opportunity to capture images and video and speak to subject matter experts. Along with viewing the adapter for Artemis II, media will be able to see the Orion stage adapter for the Artemis III mission, the first lunar landing at the Moon’s South Pole.
This event is open to U.S. media, who must confirm their attendance by 12 p.m. CDT Wednesday, Aug. 13, with Jonathan Deal in Marshall’s Office of Communications at jonathan.e.deal@nasa.gov. Media must also report by 1:30 p.m. Thursday, Aug.14 to the Redstone Arsenal Joint Visitor Control Center Gate 9 parking lot, located at the Interstate 565 interchange at Research Park Boulevard, to be escorted to the event.
Through Artemis, NASA will send astronauts to explore the Moon for scientific discovery, economic benefits, and build the foundation for the first crewed missions to Mars.
For more on SLS, visit:
https://www.nasa.gov/humans-in-space/space-launch-system
Jonathan Deal
Marshall Space Flight Center, Huntsville, Ala.
256.631.9126
jonathan.e.deal@nasa.gov
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Last Updated Aug 11, 2025 EditorBeth RidgewayLocationMarshall Space Flight Center Related Terms
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By NASA
Technicians at the Astrotech Space Operations Facility near NASA’s Kennedy Space Center in Florida conduct illumination testing on Friday, July 18, 2025, by flashing a bright light that simulates the Sun into the two-panel solar array that will help power the agency’s IMAP (Interstellar Mapping and Acceleration Probe) observatory on its upcoming journey to a destination about one million miles away from Earth Lagrange Point 1.Credit: NASA/Kim Shiflett NASA invites media to view the agency’s IMAP (Interstellar Mapping and Acceleration Probe) spacecraft and two other missions — the Carruthers Geocorona Observatory and the National Oceanic and Atmospheric Administration’s (NOAA) Space Weather Follow On–Lagrange 1 (SWFO-L1) observatory, which will launch along with IMAP as rideshares.
Media will have the opportunity to photograph the three spacecraft and speak with subject matter experts representing all three missions. The event will take place on Thursday, Aug. 28, at the Astrotech Space Operations payload processing facility in Titusville, Florida. Confirmed media will receive additional details after registering.
To participate in the event, media must RSVP by 11:59 p.m. on Tuesday, Aug. 19, by submitting their request online at: https://media.ksc.nasa.gov.
The IMAP mission will study the heliosphere, a vast magnetic bubble created by the Sun that protects our solar system from radiation incoming from interstellar space. Carruthers will use its ultraviolet cameras to monitor how material from the Sun impacts the outermost part of Earth’s atmosphere. The SWFO-L1 mission will observe solar eruptions, and monitor incoming space weather 24/7, providing early warnings and validating forecasts that protect vital communication and navigation infrastructure, economic interests, and national security, both on Earth and in space.
NASA is targeting no earlier than September for the launch of these three missions on a SpaceX Falcon 9 rocket from Launch Complex 39A at the agency’s Kennedy Space Center in Florida.
NASA’s media accreditation policy is available online. For questions about accreditation, please email: ksc-media-accreditat@mail.nasa.gov.
Facility Access
Due to spacecraft cleanliness requirements, this invitation is open to a limited number of media with no more than two individuals per media organization. This event is open to U.S. citizens who possess a valid government-issued photo identification and proof of U.S. citizenship, such as a passport or birth certificate.
Media attending this event must comply with cleanroom guidelines. This includes wearing specific cleanroom garments; avoiding cologne, cosmetics, and high-heeled shoes; cleaning camera equipment under the supervision or assistance of contamination control specialists; and placing all electronics in airplane mode in the designated areas near the spacecraft. NASA will provide detailed guidance to approved media.
Observatories Information
The three observatories are preparing to launch to Lagrange point 1, which lies about a million miles from Earth toward the Sun. There, they will orbit this gravitational balance point, holding a steady position between Earth and the Sun. NASA’s IMAP will use its 10 instruments to map the heliosphere’s edge and reveal how the Sun accelerates charged particles, filling in essential puzzle pieces to understand the space weather environment across the solar system. The mission’s varied instruments also will provide near real-time space weather data to scientists on Earth.
The Carruthers observatory will image the glow of ultraviolet light emitted by the uppermost parts of Earth’s atmosphere — called the geocorona — to help researchers understand how our planet’s atmosphere is shaped by conditions in space. NOAA’s SWFO-L1 will use its suite of instruments to sample the solar wind and interplanetary magnetic field, while its onboard coronagraph will detect coronal mass ejections and other solar events. Together, these real-time observations of space weather enable precautionary actions to protect satellites, power grids, aviation, and communication and navigation technology.
Learn more about NASA’s IMAP at:
https://science.nasa.gov/mission/imap/
-end-
Abbey Interrante
Headquarters, Washington
301-201-0124
abbey.a.interrante@nasa.gov
Sarah Frazier
Goddard Space Flight Center, Greenbelt, Md.
202-853-7191
sarah.frazier@nasa.gov
Leejay Lockhart
Kennedy Space Center, Florida
321-747-8310
leejay.lockhart@nasa.gov
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Last Updated Aug 08, 2025 LocationNASA Headquarters Related Terms
NASA Headquarters Carruthers Geocorona Observatory (GLIDE) Goddard Space Flight Center Heliophysics Heliophysics Division IMAP (Interstellar Mapping and Acceleration Probe) Kennedy Space Center Space Weather The Sun View the full article
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