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NASA’s Juno Provides High-Definition Views of Europa’s Icy Shell
Imagery from the solar-powered spacecraft shows some intriguing features on the ice-encased Jovian moon.
Images from the JunoCam visible-light camera aboard NASA’s Juno spacecraft supports the theory that the icy crust at the north and south poles of Jupiter’s moon Europa is not where it used to be. Another high-resolution picture of the icy moon, by the spacecraft’s Stellar Reference Unit (SRU), reveals signs of possible plume activity and an area of ice shell disruption where brine may have recently bubbled to the surface.
The JunoCam results recently appeared in the Planetary Science Journal and the SRU results in the journal JGR Planets.
On Sept. 29, 2022, Juno made its closest flyby of Europa, coming within 220 miles (355 kilometers) of the moon’s frozen surface. The four pictures taken by JunoCam and one by the SRU are the first high-resolution images of Europa since Galileo’s last flyby in 2000.
True Polar WanderJuno’s ground track over Europa allowed imaging near the moon’s equator. When analyzing the data, the JunoCam team found that along with the expected ice blocks, walls, scarps, ridges, and troughs, the camera also captured irregularly distributed steep-walled depressions 12 to 31 miles (20 to 50 kilometers) wide. They resemble large ovoid pits previously found in imagery from other locations of Europa.
This black-and-white image of Europa’s surface was taken by the Stellar Reference Unit (SRU) aboard NASA’s Juno spacecraft during the Sept. 29, 2022, flyby. The chaos feature nicknamed “the Platypus” is seen in the lower right corner.NASA/JPL-Caltech/SwRI This annotated image of Europa’s surface from Juno’s SRU shows the location of a double ridge running east-west (blue box) with possible plume stains and the chaos feature the team calls “the Platypus” (orange box). These features hint at current surface activity and the presence of subsurface liquid water on the icy Jovian moon.A giant ocean is thought to reside below Europa’s icy exterior, and these surface features have been associated with “true polar wander,” a theory that Europa’s outer ice shell is essentially free-floating and moves.
“True polar wander occurs if Europa’s icy shell is decoupled from its rocky interior, resulting in high stress levels on the shell, which lead to predictable fracture patterns,” said Candy Hansen, a Juno co-investigator who leads planning for JunoCam at the Planetary Science Institute in Tucson, Arizona. “This is the first time that these fracture patterns have been mapped in the southern hemisphere, suggesting that true polar wander’s effect on Europa’s surface geology is more extensive than previously identified.”
The high-resolution JunoCam imagery has also been used to reclassify a formerly prominent surface feature from the Europa map.
“Crater Gwern is no more,” said Hansen. “What was once thought to be a 13-mile-wide impact crater — one of Europa’s few documented impact craters — Gwern was revealed in JunoCam data to be a set of intersecting ridges that created an oval shadow.”
The PlatypusAlthough all five Europa images from Juno are high-resolution, the image from the spacecraft’s black-and-white SRU offers the most detail. Designed to detect dim stars for navigation purposes, the SRU is sensitive to low light. To avoid over-illumination in the image, the team used the camera to snap the nightside of Europa while it was lit only by sunlight scattered off Jupiter (a phenomenon called “Jupiter-shine”).
This innovative approach to imaging allowed complex surface features to stand out, revealing intricate networks of cross-cutting ridges and dark stains from potential plumes of water vapor. One intriguing feature, which covers an area 23 miles by 42 miles (37 kilometers by 67 kilometers), was nicknamed by the team “the Platypus” because of its shape.
Characterized by chaotic terrain with hummocks, prominent ridges, and dark reddish-brown material, the Platypus is the youngest feature in its neighborhood. Its northern “torso” and southern “bill” — connected by a fractured “neck” formation — interrupt the surrounding terrain with a lumpy matrix material containing numerous ice blocks that are 0.6 to 4.3 miles (1 to 7 kilometers) wide. Ridge formations collapse into the feature at the edges of the Platypus.
For the Juno team, these formations support the idea that Europa’s ice shell may give way in locations where pockets of briny water from the subsurface ocean are present beneath the surface.
About 31 miles (50 kilometers) north of the Platypus is a set of double ridges flanked by dark stains similar to features found elsewhere on Europa that scientists have hypothesized to be cryovolcanic plume deposits.
“These features hint at present-day surface activity and the presence of subsurface liquid water on Europa,” said Heidi Becker, lead co-investigator for the SRU at NASA’s Jet Propulsion Laboratory in Southern California, which also manages the mission. “The SRU’s image is a high-quality baseline for specific places NASA’s Europa Clipper mission and ESA’s (European Space Agency’s) Juice missions can target to search for signs of change and brine.”
Europa Clipper’s focus is on Europa — including investigating whether the icy moon could have conditions suitable for life. It is scheduled to launch on the fall of 2024 and arrive at Jupiter in 2030. Juice (Jupiter Icy Moons Explorer) launched on April 14, 2023. The ESA mission will reach Jupiter in July 2031 to study many targets (Jupiter’s three large icy moons, as well as fiery Io and smaller moons, along with the planet’s atmosphere, magnetosphere, and rings) with a special focus on Ganymede.
Juno executed its 61st close flyby of Jupiter on May 12. Its 62nd flyby of the gas giant, scheduled for June 13, includes an Io flyby at an altitude of about 18,200 miles (29,300 kilometers).
More About the MissionJPL, a division of Caltech in Pasadena, California, manages the Juno mission for the principal investigator, Scott Bolton, of the Southwest Research Institute in San Antonio. Juno is part of NASA’s New Frontiers Program, which is managed at NASA’s Marshall Space Flight Center in Huntsville, Alabama, for the agency’s Science Mission Directorate in Washington. The Italian Space Agency (ASI) funded the Jovian InfraRed Auroral Mapper. Lockheed Martin Space in Denver built and operates the spacecraft.
More information about Juno is available at:
News Media ContactsDC Agle
Jet Propulsion Laboratory, Pasadena, Calif.
818-393-9011
agle@jpl.nasa.gov
Karen Fox / Charles Blue
NASA Headquarters, Washington
301-286-6284 / 202-802-5345
karen.c.fox@nasa.gov / charles.e.blue@nasa.gov
Deb Schmid
Southwest Research Institute, San Antonio
210-522-2254
dschmid@swri.org
2024-066
Share Details Last Updated May 15, 2024 Related Terms Explore More 5 min read 5 Things to Know About NASA’s Tiny Twin Polar Satellites Article 18 hours ago 19 min read The Next Full Moon is the Flower, Corn, or Corn Planting MoonThe Next Full Moon is the Flower, Corn, or Corn Planting Moon; the Milk Moon;…
Article 20 hours ago 3 min read Binoculars: A Great First TelescopeDo you want to peer deeper into the night sky? Are you feeling the urge…
Article 1 day agoDiscovery Alert: An Earth-sized World and Its Ultra-cool Star
4 min read
Discovery Alert: An Earth-sized World and Its Ultra-cool Star An artist’s concept of the exoplanet SPECULOOS-3 b orbiting its red dwarf star. The planet is as big around as Earth, while its star is slightly bigger than Jupiter – but much more massive.Credit: NASA/JPL-CaltechOur galaxy is a jewel box of red stars. More than 70% of the stars in the Milky Way are M dwarfs, also known as red dwarfs. These stars are cool and dim compared with our Sun, but they often blast orbiting exoplanets with high-energy radiation, especially early in their lives. And those ‘‘lives’’ last a long time. Stars like our Sun burn for about 10 billion years before turning into hungry red giants devouring any planets too nearby. M dwarfs keep burning for 100 billion years or more, perhaps offering a foothold for life, and an even longer window for life to develop.
An international team using robotic telescopes around the world recently spotted an Earth-sized planet orbiting an ultra-cool red dwarf, the dimmest and longest-lived of stars. When the universe grows cold and dark, these will be the last stars burning.
The DiscoveryThe exoplanet SPECULOOS-3 b is about 55 light-years from Earth (really close when you consider the cosmic scale!) and nearly the same size. A year there, one orbit around the star, takes about 17 hours. The days and nights, though, may never end: The planet is thought to be tidally locked, so the same side, known as the dayside, always faces the star, like the Moon to Earth. The nightside would be locked in never-ending darkness.
The DetailsIn our corner of the galaxy, ultra-cool dwarf stars are ubiquitous. They are so faint that their planetary population is largely unexplored. The SPECULOOS (Search for Planets EClipsing ULtra-cOOl Stars) project, led by Michael Gillon at the University of Liège, Belgium, was designed to change that. Ultra-cool dwarf stars are scattered across the sky, so you need to observe them one by one, for weeks, to get a good chance to detect transiting planets. For that, you need a dedicated network of professional telescopes. This is the concept of SPECULOOS.
‘‘We designed SPECULOOS specifically to explore nearby ultra-cool dwarf stars in search of rocky planets,’’ Gillon said. ‘‘With the SPECULOOS prototype and the crucial help of the NASA Spitzer Space Telescope, we discovered the famous TRAPPIST-1 system. That was an excellent start!’’
Gillon is the lead author of the paper announcing the planet’s discovery, published May 15, 2024, in Nature Astronomy. The project is a true international endeavor, with partnership with the Universities of Cambridge, Birmingham, Bern, Massachusetts Institute of Technology, and ETH Zürich.
The SPECULOOS-3 star is thousands of degrees cooler than our Sun with an average temperature of about 4,760 F (2,627 C), but it pummels its planet with radiation, meaning there’s likely no atmosphere.
Seeing the star, let alone the planet, is a feat in itself. “Though this particular red dwarf is more than a thousand times dimmer than the Sun, its planet orbits much, much closer than the Earth, heating up the planetary surface,” said co-author Catherine Clark, a postdoctoral researcher at NASA’s Jet Propulsion Laboratory in Southern California.
Fun facts- While the planet is as big around as Earth, its star is just a tad bigger than Jupiter – but much more massive.
- The planet receives almost 16 times more energy per second than Earth receives from the Sun.
- Did you catch the cookie connection? The planet-finding program SPECULOOS shares its name with the spiced shortbread. Both hail from Belgium. Sweet!
SPECULOOS-3 b is an excellent candidate for followup observations by the James Webb Space Telescope. Not only might we learn about the potential for an atmosphere and about the surface mineralogy, but it might also help us understand the stellar neighborhood and our place in it.
‘‘We’re making great strides in our study of planets orbiting other stars. We have now reached the stage where we can detect and study Earth-sized exoplanets in detail. The next step will be to determine whether any of them are habitable, or even inhabited,’’ said Steve B. Howell, one of the planet’s discoverers at NASA Ames Research Center in Silicon Valley.
This story was written by the late Kristen Walbolt, who managed both exoplanets.nasa.gov and @NASAExoplanets social accounts, growing the latter from a following of 126,000 to over 1.9 million in just five years. This Discovery Alert and the associated illustration are among the final pieces of Kristen’s work for NASA Exoplanets.
Share Details Last Updated May 15, 2024 Related Terms Explore More 7 min read NASA’s Webb Hints at Possible Atmosphere Surrounding Rocky Exoplanet Article 1 week ago 6 min read Breaking the Scaling Limits: New Ultralow-noise Superconducting Camera for Exoplanet Searches Article 1 week ago 6 min read NASA’s Webb Maps Weather on Planet 280 Light-Years Away Article 2 weeks ago Keep Exploring Discover Related TopicsMissions
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NASA’s X-59 Passes Milestone Toward Safe First Flight
4 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater) NASA’s X-59 quiet supersonic research aircraft sits on the ramp at Lockheed Martin Skunk Works in Palmdale, California during sunrise, shortly after completion of painting. With its unique design, including a 38-foot-long nose, the X-59 was built to demonstrate the ability to fly supersonic, or faster than the speed of sound, while reducing the typically loud sonic boom produced by aircraft at such speeds to a quieter sonic “thump”. The X-59 is the centerpiece of NASA’s Quesst mission, which seeks to solve one of the major barriers to supersonic flight over land, currently banned in the United States, by making sonic booms quieter. NASA/Steve FreemanNASA has taken the next step toward verifying the airworthiness for its quiet supersonic X-59 aircraft with the completion of a milestone review that will allow it to progress toward flight.
A Flight Readiness Review board composed of independent experts from across NASA has completed a study of the X-59 project team’s approach to safety for the public and staff during ground and flight testing. The review board looked in detail at the project team’s analysis of potential hazards, focusing on safety and risk identification.
Flight Readiness Review is the first step in the flight approval process. The board’s work will provide the X-59 team with insights and recommendations toward systems checkouts on the ground and first flight.
“It’s not a pass-fail,” said Cathy Bahm, NASA’s Low Boom Flight Demonstrator project manager. “We’ll be getting actions from the board and will work with them to resolve those and work toward the Airworthiness and Flight Safety Review.”
NASA and prime contractor Lockheed Martin Skunk Works are developing the X-59 to reduce the sound of a sonic boom to a quieter “thump.” The aircraft is at the center of NASA’s Quesst mission, which will use it to gather data that could revolutionize air travel, potentially paving the way for a new generation of commercial aircraft that can travel faster than the speed of sound. Commercial supersonic flight over land has been banned for more than 50 years because of the noise of sonic booms.
“The Flight Readiness Review focused on specific aspects of the X-59 team’s work on the aircraft, but also served as an overview and update on the entire project,” said Jay Brandon, chief engineer for the Low Boom Flight Demonstrator project.
“It gave us the opportunity to stop working for a minute and gather what we’ve done so we could tell our story, not just to the board, but to the whole project team,” Brandon said.
With the Flight Readiness Review complete, the upcoming Airworthiness and Flight Safety Review will be the next safety milestone. The Airworthiness and Flight Safety Review board includes senior leaders from several NASA centers and Skunk Works. It will review findings from the Flight Readiness Review, as well as the project team’s response to those filings. The board will send a recommendation to NASA Armstrong’s center director, who signs the airworthiness certificate.
Finally, the team will provide a technical brief to another review board based on test objectives, how the tests are being carried out, the risks involved, and the risk-mitigation actions the team has taken. The X-59 team would have to address any issues raised in the brief before the board, led by NASA Armstrong chief engineer Cynthia J. “CJ” Bixby, will sign a flight request.
“It’s really an exciting time on the project,” Bahm said. “It’s not an easy road, but there’s a finite set of activities that are in front of us.”
NASA Deputy Administrator Pam Melroy speaks on stage immediately following the unveiling of the agency’s X-59 quiet supersonic research aircraft at a January 12, 2024 event at Lockheed Martin Skunk Works in Palmdale, California. The X-59 is the centerpiece of NASA’s Quesst mission, which seeks to solve one of the major barriers to supersonic flight over land, currently banned in the United States, by making sonic booms quieter.NASA/Steve Freeman The Path ForwardThere are significant steps to be completed before flights can begin. The X-59 team is preparing for upcoming major ground tests focused on systems integration engine runs, and electromagnetic interference.
The X-59 aircraft is a bold, new design, but many of its components are from well-established aircraft, including landing gear from an Air Force F-16 fighter, a cockpit canopy from a NASA T-38 trainer, and a control stick from an Air Force F-117 stealth fighter are among those parts.
“None of these systems have ever worked and played together before,” said Brad Neal, chairman for the X-59 Airworthiness and Flight Safety Review board. “It’s a brand-new thing that we are developing, even though they’re components that have been on different legacy aircraft. As we get into integration testing here, it’s going to be a great opportunity to learn.’’
Share Details Last Updated May 15, 2024 EditorDede DiniusLocationArmstrong Flight Research Center Related Terms Explore More 4 min read NASA Teammates Recall Favorite Memories Aboard Flying Laboratory Article 1 day ago 5 min read Meet NASA Women Behind World’s Largest Flying Laboratory Article 2 days ago 3 min read NASA Licenses 3D-Printable Superalloy to Benefit US Economy Article 6 days ago Keep Exploring Discover More Topics From NASAArmstrong Flight Research Center
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Good Night, Moon
Good Night, Moon
The waning gibbous moon stands out against the dark backdrop of space in this April 26, 2024, image from the International Space Station. Waning gibbous is one of eight moon phases, occurring after the full moon. The Sun always illuminates half of the Moon while the other half remains dark, but how much we can see of that illuminated half changes as the Moon travels through its orbit. As the Moon begins its journey back toward the Sun, the lighted side appears to shrink, but the Moon’s orbit is simply carrying it out of view from our perspective.
See NASA’s interactive map for observing the Moon—from Earth—every day of the year.
Image Credit: NASA
Hubble Views the Dawn of a Sun-like Star
2 min read
Hubble Views the Dawn of a Sun-like Star This NASA Hubble Space Telescope image captures a triple-star star system. NASA, ESA, G. Duchene (Universite de Grenoble I); Image Processing: Gladys Kober (NASA/Catholic University of America)Download this image
Looking like a glittering cosmic geode, a trio of dazzling stars blaze from the hollowed-out cavity of a reflection nebula in this new image from NASA’s Hubble Space Telescope. The triple-star system is made up of the variable star HP Tau, HP Tau G2, and HP Tau G3. HP Tau is known as a T Tauri star, a type of young variable star that hasn’t begun nuclear fusion yet but is beginning to evolve into a hydrogen-fueled star similar to our Sun. T Tauri stars tend to be younger than 10 million years old ― in comparison, our Sun is around 4.6 billion years old ― and are often found still swaddled in the clouds of dust and gas from which they formed.
As with all variable stars, HP Tau’s brightness changes over time. T Tauri stars are known to have both periodic and random fluctuations in brightness. The random variations may be due to the chaotic nature of a developing young star, such as instabilities in the accretion disk of dust and gas around the star, material from that disk falling onto the star and being consumed, and flares on the star’s surface. The periodic changes may be due to giant sunspots rotating in and out of view.
The box in the ground-based image reveals the location of Hubble’s view within the wider context of this triple-star system. NASA, ESA, G. Duchene (Universite de Grenoble I); Image Processing: Gladys Kober (NASA/Catholic University of America); Inset: KPNO/NOIRLab/NSF/AURA/T.A. Rector (University of Alaska Anchorage/NSF’s NOIRLab)Curving around the stars, a cloud of gas and dust shines with their reflected light. Reflection nebulae do not emit visible light of their own, but shine as the light from nearby stars bounces off the gas and dust, like fog illuminated by the glow of a car’s headlights.
HP Tau is located approximately 550 light-years away in the constellation Taurus. Hubble studied HP Tau as part of an investigation into protoplanetary disks, the disks of material around stars that coalesce into planets over millions of years.
Media Contact:
Claire Andreoli
NASA’s Goddard Space Flight Center, Greenbelt, MD
claire.andreoli@nasa.gov
Since its 1990 launch, the Hubble Space Telescope has changed our fundamental understanding of the universe.
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Space Physics and Space Weather Scientist Dr. Yihua (Eva) Zheng
“I grew up in China. In China, everybody talks about what they want to be [when they grow up]. Many want to grow up to be a scientist or engineer. So I aspired to be a scientist from an early age.
“… For the girls or women in science — or in any profession or job — opportunities are more abundant than they were previously. Sometimes you need to take bold steps. Just a little push, and then you will get there. I initially started as a foreign national, so not a lot of opportunities existed for a foreign national, and some of them [required a] green card or citizenship. I think it’s hard, but still, there is a path forward. I think it’s important to work hard and be optimistic, and you will find something.”
—Dr. Yihua (Eva) Zheng, Space Physics and Space Weather Scientist, Heliophysics Science Division, NASA’s Goddard Space Flight Center
Image Credit: NASA/Thalia Patrinos
Interviewer: NASA/Thalia Patrinos
Binoculars: A Great First Telescope
3 min read
Binoculars: A Great First Telescope A pair of good binoculars can show craters on the Moon around 6 miles (10 km) across and larger. How large is that? It would take you about two hours to hike across a similar-sized crater on Earth. The “Can You See the Flag On the Moon?” handout showcases the levels of detail that different instruments can typically observe on the Moon. Jay TannerDo you want to peer deeper into the night sky? Are you feeling the urge to buy a telescope? There are so many options for budding astronomers that choosing one can be overwhelming. A first telescope should be easy to use and provide good quality views while being affordable. As it turns out, those requirements make the first telescope of choice for many stargazers something unexpected: a good pair of binoculars!
Binoculars are an excellent first instrument because they are generally easy to use and more versatile than most telescopes. Binoculars can be used for activities like stargazing and birdwatching and work great in the field at a star party, along the hiking trail, and anywhere else where you can see the sky. Binoculars also travel well, since they easily fit into carry-on luggage – a difficult feat for most telescopes! A good pair of binoculars, ranging in specifications from 7×35 to 10×50, will give you great views of the Moon, large open star clusters like the Pleiades (M45), and, from dark skies, larger bright galaxies like the Andromeda Galaxy (M31) and large nebulae like the Orion Nebula (M42). While you likely won’t be able to see Saturn’s rings, as you practice your observing skills you may be able to spot Jupiter’s moons, along with some globular clusters and fainter nebulae from dark sites, too.
The two most popular types of binocular designs are shown here: roof-prism binoculars (left) and porro-prism binoculars (right). Roof prisms tend to be more compact, lighter, and a bit more portable, while porro-prisms tend to be heavier but often offer wider views and greater magnification. What should you choose? Many birders and frequent fliers often choose roof-prism models for their portability. Many observers who prefer to observe fainter deep-sky objects or who use a tripod with their observing choose larger porro-prism designs. There is no right answer, so if you can, try out both designs and see which works better for you. Astronomical Society of the PacificWhat do the numbers on those binocular specs actually mean? The first number is the magnification, while the second number is the size in millimeters (mm) of the lenses. So, a 7×35 pair of binoculars means that they will magnify 7 times using lenses 35 mm in diameter. It can be tempting to get the biggest binoculars you can find but try not to get anything much more powerful than a 10×50 pair at first. Larger binoculars with more power often have narrower fields of vision and are heavier; while technically more powerful, they are also more difficult to hold steadily in your hands and “jiggle” quite a bit unless you buy much more expensive binoculars with image stabilization or mount them to a tripod.
Would it surprise you that amazing views of some astronomical objects can be found not just from giant telescopes, but also from seemingly humble binoculars? Binoculars are able to show a much larger field of view of the sky compared to most telescopes. For example, most telescopes are unable to keep the entirety of the Pleiades or Andromeda Galaxy entirely inside the view of most eyepieces. Binoculars are also a great investment for more advanced observing, as later on they are useful for tracking down objects to then observe in more detail with a telescope.
If you are able to do so, real-world advice and experience is still the best for something you will be spending a lot of time with! Going to an in-person star party hosted by a local astronomy club is a great way to get familiar with telescopes and binoculars of all kinds – just ask permission before taking a closer look! You can find clubs and star parties near you on the Night Sky Network’s Clubs & Events page at bit.ly/nsnclubsandevents and inspire your binocular stargazing sessions with NASA’s latest discoveries!
Originally posted by Dave Prosper: November 2022
Last Updated by Kat Troche: April 2024
