NASA's Voyager 1 Revealed A Stunning Discovery At The Edge Of Our Solar System
Nicolae Bochis
Sun, October 5, 2025
BGR
Image of a Voyager space probe - Artsiom P/Shutterstock
Voyager 1, launched in 1977, has traveled farther than any spacecraft in human history. After more than four decades of silent endurance through space, it now sails beyond the orbit of the outer planets of the solar system. Its mission has transcended planetary flybys; it's now humanity's first direct way to explore interstellar space. NASA has used radio to talk to Voyager 1 as it stumbled upon something astonishing hiding at the farthest reaches of our solar system: a mysterious "wall of fire." This may sound like it came right out of a sci-fi story, yet it's part of the very real final frontier where no man has gone before. What this "wall of fire" truly represents is still being investigated, but it is shown to be the heliopause — in other words, the borderline where our sun stops having any influence on anything beyond it.
This outer layer is created by the solar winds interacting with interstellar gases, which results in superheated plasma. Voyager discovered that this remote region of our solar system reaches extremely hot temperatures of 30,000 to 50,000 Kelvin (54,000 to 90,000 degrees Fahrenheit). Fortunately for spacecraft like Voyager, the particle density is too low for this heat to be transferred, so we can continue sending out probes without the risk of overheating. But this discovery at the edge of our solar system is more than merely a scientific milestone.
Read more: What Does Space Actually Smell Like? Here's What Scientists Say
The extremes of the heliopause
Depiction of the heliopause - NASA/IBEX/Adler Planetarium/Wikimedia Commons
What scientists are calling the "wall of fire" is more formally known as the heliopause. It's the invisible boundary that marks the outermost edge of the sun's influence. The heliosphere is a vast bubble in which the solar wind — a stream of charged particles constantly blowing outwards from the sun — shields our solar system from harsh radiation that comes from interstellar space. However, that protective influence has a limit. At a certain point, the solar wind collides with the ionized gas and plasma (and other particles known as the interstellar medium) between the stars, slowing, compressing, and creating a turbulent frontier.
It's not only the existence of the heliopause that's so striking; it's also the unexpected extremes that Voyager 1 has discovered there (not to mention a strange hum). As the spacecraft got closer to this boundary, its instruments recorded sudden changes in particle density and magnetic fields. These are the signatures of a region far more turbulent than scientists imagined. Instead of a smooth and gradual fade between solar and interstellar space, Voyager 1 found abrupt shifts, almost like stepping over a threshold.
The most surprising revelation was the temperature dynamics. Near the heliopause, charged particles become trapped and compressed, creating zones of extraordinary heat. Other nearby regions remain relatively cooler. This produces a patchwork of hot and cold plasma, unlike anything observed inside the heliosphere. That's why this contrast was nicknamed "the wall of fire," evoking an image of fiery clashes of energy at the boundary of the solar system.
The magnetic environment added another twist. Voyager 1 detected magnetic field lines that appeared stronger and more orderly than expected. That suggests that the interstellar magnetic fields may be pressing harder against the heliosphere than previously believed. This tension between magnetic fields is what shapes the boundary and warps it like a balloon under pressure.
Voyage through the wall of fire
Depiction of Voyager 1's view of the solar system - NASA, ESA, and G. Bacon (STScI)/Wikimedia Commons
Together, these discoveries reveal that the edge of our solar system is not a quiet fade into the galactic vastness, but a dynamic frontier. Forces from within and beyond clash and shape each other in unpredictable ways. For scientists, the solar system frontier is a laboratory in its own right, where natural experiments unfold to reveal how stars and their planetary systems carve out bubbles in the galaxy.
Voyager 1 is now traveling through interstellar space, and each measurement it makes is unprecedented, a first for humanity. It has already crossed into the region where the solar wind is weak. There, the magnetic fields grow more complex, and particles from beyond our solar system begin to dominate. What's more, the heliopause is not a solid wall, but a dynamic, shifting interface between two realms. It separates the familiar space where our sun governs, and the vast, unknown territory beyond the confines of our solar system. Voyager 1 probing this frontier helps scientists answer questions on how our solar system interacts with the rest of our galaxy and how far the sun's influence really extends. What lies in the space beyond?
Each faint signal Voyager 1 sends back to Earth has to travel more than 24 billion kilometers to reach us, and each of those signals is just a fragment of the answer. But now we know that our solar system doesn't just end abruptly: It transitions into a complex and fiery border with the rest of the galaxy.
We Finally Know How The Lights Switched on at The Dawn of Time
Michelle Starr
Sat, October 4, 2025
SCIENCE ALERT
We may finally know what first lit up the cosmic dawn in the early Universe.
According to data from the Hubble and James Webb Space Telescopes, the origins of the free-flying photons in the early cosmic dawn were small dwarf galaxies that flared to life, clearing the fog of murky hydrogen that filled intergalactic space. A paper about the research was published in February 2024.
"This discovery unveils the crucial role played by ultra-faint galaxies in the early Universe's evolution," said astrophysicist Iryna Chemerynska of the Institut d'Astrophysique de Paris.
We may finally know what first lit up the cosmic dawn in the early Universe.
According to data from the Hubble and James Webb Space Telescopes, the origins of the free-flying photons in the early cosmic dawn were small dwarf galaxies that flared to life, clearing the fog of murky hydrogen that filled intergalactic space. A paper about the research was published in February 2024.
"This discovery unveils the crucial role played by ultra-faint galaxies in the early Universe's evolution," said astrophysicist Iryna Chemerynska of the Institut d'Astrophysique de Paris.
"They produce ionizing photons that transform neutral hydrogen into ionized plasma during cosmic reionization. It highlights the importance of understanding low-mass galaxies in shaping the Universe's history."
Related: 7 Baffling Space Mysteries We're Dying For Scientists to Solve
At the beginning of the Universe, within minutes of the Big Bang, space was filled with a hot, dense fog of ionized plasma. What little light there was wouldn't have penetrated this fog; photons would simply have scattered off the free electrons floating around, effectively making the Universe dark.
As the Universe cooled, after about 300,000 years, protons and electrons began to come together to form neutral hydrogen (and a little bit of helium) gas.
Most wavelengths of light could penetrate this neutral medium, but there was very little in the way of light sources to produce it. But from this hydrogen and helium, the first stars were born.
Those first stars delivered radiation that was strong enough to peel electrons away from their nuclei and reionize the gas. By this point, however, the Universe had expanded so much that the gas was diffuse, and could not prevent light from shining out.
By about 1 billion years after the Big Bang, the end of the period known as the cosmic dawn, the Universe was entirely reionized. Ta-da! The lights were on.
But because there's so much murk in the cosmic dawn, and because it's so dim and far away across time and space, we've had trouble seeing what's there.
Scientists thought that the sources responsible for most of the clearing must have been powerful – huge black holes whose accretion produces blazing light, for example, and large galaxies in the throes of star formation (baby stars produce a lot of UV light).
JWST was designed, in part, to peer into the cosmic dawn and try to see what lurks therein. It's been very successful, revealing all sorts of surprises about this crucial time in the formation of our Universe. Surprisingly, the telescope's observations now suggest that dwarf galaxies are the key player in reionization.
A JWST deep field image with some of the sources the researchers identified as drivers of reionization. (Hakim Atek/Sorbonne University/JWST)
An international team led by astrophysicist Hakim Atek of the Institut d'Astrophysique de Paris turned to JWST data on a galaxy cluster called Abell 2744, backed up by data from Hubble.
Abell 2744 is so dense that space-time warps around it, forming a cosmic lens; any distant light traveling to us through that space-time becomes magnified. This allowed the researchers to see tiny dwarf galaxies close to the cosmic dawn.
Then, they used JWST to obtain detailed spectra of these tiny galaxies. Their analysis revealed that, not only are these dwarf galaxies the most abundant galaxy type in the early Universe, they are far brighter than expected.
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In fact, the team's research shows that dwarf galaxies outnumber large galaxies by 100 to 1, and their collective output is four times the ionizing radiation usually assumed for larger galaxies.
"These cosmic powerhouses collectively emit more than enough energy to get the job done," Atek said.
"Despite their tiny size, these low-mass galaxies are prolific producers of energetic radiation, and their abundance during this period is so substantial that their collective influence can transform the entire state of the Universe."
The field of view for Abell 2744. An estimated 50,000 sources of near-infrared light are represented in this image. (NASA, ESA, CSA, I. Labbe/Swinburne University of Technology, R. Bezanson/University of Pittsburgh, A. Pagan/STScI)More
It's the best evidence yet for the force behind reionization, but there's more work to be done. The researchers looked at one small patch of the sky; they need to make sure that their sample isn't just an anomalous cluster of dwarf galaxies, but is a representative sample of the entire population in the cosmic dawn.
They intend to study more cosmic lens regions of the sky to obtain a wider sample of early galactic populations. But just on this one sample, the results are incredibly exciting. Scientists have been chasing answers on reionization for as long we've known about it. We're on the brink of finally blowing away the fog.
"We have now entered uncharted territory with the JWST," said astrophysicist Themiya Nanayakkara of Swinburne University of Technology in Australia.
"This work opens up more exciting questions that we need to answer in our efforts to chart the evolutionary history of our beginnings."
The research has been published in Nature.
This NASA Satellite Sent The First Radar Images Of Earth's Surface And The Results Are Very Clear
Max Miller
Sat, October 4, 2025
SlashGear.
Rendering of the NISAR satellite orbiting Earth - NASA
New images of Earth's surface were captured by the NISAR satellite, marking a milestone in a joint space mission between India and the United States. The images depict portions of Maine and North Dakota and were taken with a specialized radar capable of new levels of topographical detail, and which is expected to help predict natural disasters.
Satellite NISAR, short for the NASA-ISRO Synthetic Aperture Radar, was launched on July 30, and the newly released images were captured on August 21. The images of Maine's coast show an incredible level of detail, with buildings and other hard surfaces clearly differentiated from dense forest and open water. Meanwhile, the images of North Dakota reveal distinctions between forest and wetland, cultivated and fallow fields, and the Forest River versus irrigation systems.
NASA Associate Administrator Amit Kshatriya emphasized the future scientific achievements heralded by the images from NISAR, as well as the deepening collaboration between India and the United States that they represent in an era of increasingly privatized space exploration. In a press release, Kshatriya stated that "By understanding how our home planet works, we can produce models and analysis of how other planets in our solar system and beyond work." But there are more immediate implications for the technology here on Earth, and this may be only the beginning of a new era for development and even disaster prevention.
NISAR will aid climate forecasting and disaster preparation efforts
Coastal Maine captured by NISAR satellite - NASA Jet Propulsion Laboratory
The images captured by NISAR were taken using the satellite's titular L-band synthetic aperture radar (SAR), which could prove a valuable tool for understanding the pace and scale of climate change, as well as for disaster preparation efforts and forecasting. It works by emitting an energy pulse, which bounces off Earth and is recaptured by the satellite. Compared to traditional photography — even advanced satellite photography — SAR interacts with the physical terrain it captures to give researchers a detailed picture of water bodies, forests, and even soil. An S-band radar is also onboard, which is more suited to vegetation close to the ground. The technology overcomes a variety of obstacles to using radar in space, including the distance from satellite to ground and the speed of its travel.
According to Nicky Fox, the associate administrator of NASA's Science Mission Directorate, NISAR imagery will produce "data and insights that will enable scientists to study Earth's changing land and ice surfaces in unprecedented detail while equipping decision-makers to respond to natural disasters and other challenges." In addition to monitoring agricultural conditions and certain natural ecosystems, NISAR photography will track signs of natural disasters from volcanic eruptions to earthquakes and even landslides. As natural disasters increase with the pace of climate change, NISAR will provide insights for flood mapping, wildfires, oil slicks, glacial motion, and land subsidence, among others. It can track movements down to a centimeter and will continuously monitor the Earth, making two full rotations every 12 days.
NISAR is the result of international scientific collaboration
North Dakota farmland captured by NISAR satellite - NASA Jet Propulsion Laboratory
The images from the NISAR satellite are the culmination of over a decade's worth of scientific collaboration between the United States and India. The satellite takes its name from the respective names of NASA and ISRO (the Indian Space Research Organization), which began their collaboration nearly 11 years ago in September 2014. Both countries are large and climate diverse, with enormous agricultural sectors and potential hazards. The benefit of synthetic aperture radar technology for each nation was clear enough, and as NASA began to explore the technology, ISRO identified complementary mission objectives and signed on.
NISAR was initially meant to launch in 2024, but it was pushed back to 2025 when NASA discovered that the satellite's antenna was at risk of exposure to high temperatures. In order to resolve the issue, a special coating was added. Even after that work was completed, the launch had to wait until after February 2025 to avoid putting NISAR into an orbit that would also expose it to fluctuating temperatures.
NISAR finally launched from the Satish Dhawan Space Centre at Sriharikota in Andhra Pradesh, India, at 6 p.m. on July 30. With the satellite now in orbit and its first images taken as proof of the mission's success, it is expected to continue taking images and measurements that can be used to advance scientific research. It is currently on a baseline mission of three years, though it's likely the joint project will continue in some fashion if it continues to bear out. NASA, for its part, has big plans, with its next major venture being a lunar mission over 50 years since the last one.
Planet Y? Astronomers find fresh clues of hidden world in our solar system
Jacopo Prisco, CNN
Fri, October 3, 2025
An illustration showing Planet Nine, a hypothetical, undiscovered planet in our solar system. New research now suggests the possibility of Planet Y, which would be smaller and orbiting closer to the sun than Planet Nine. - NASA
The search for an unknown planet in our solar system has inspired astronomers for more than a century. Now, a recent study suggests a potential new candidate, which the paper’s authors have dubbed Planet Y.
The planet has not been detected but merely inferred by the tilted orbits of some distant objects in the Kuiper Belt — a large ring of icy bodies beyond Neptune’s orbit. Something, the researchers said, must be disturbing these orbits and tilting them.
“One explanation is the presence of an unseen planet, probably smaller than the Earth and probably bigger than Mercury, orbiting in the deep outer solar system,” said lead author Amir Siraj, an astrophysicist and a doctoral candidate in the department of astrophysical sciences at Princeton University. “This paper is not a discovery of a planet, but it’s certainly the discovery of a puzzle for which a planet is a likely solution.” Siraj and his coauthors reported their findings in the journal Monthly Notices of the Royal Astronomical Society: Letters.
Planet Y is the latest in a series of hypothetical solar system planets that scientists have proposed in recent years, all with slightly different characteristics but collectively believed to be lurking in the Kuiper Belt — also home to Pluto, the former ninth planet that was demoted and reclassified as a dwarf planet in 2006.
Pluto as seen by NASA's New Horizons spacecraft, which captured this view in 2015. - NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute
The reason so many “ninth planet” candidates have emerged is that the Kuiper Belt is a dark, faraway region of the solar system and observations are difficult and incomplete. But such obstacles are likely to change, as a new telescope called the Vera C. Rubin Observatory is gearing up to start its 10-year survey of the night sky.
“I think within the first two to three years, it’ll become definitive,” Siraj said. “If Planet Y is in the field of view of the telescope, it will be able to find it directly.”
A heated debate
After the discovery of Neptune in 1846, astronomers kept searching for another solar system planet, which in the early 20th century became known as Planet X, a name popularized by astronomer Percival Lowell. He suspected that anomalies in the orbits of Neptune and Uranus were due to an undiscovered, distant body
When Pluto was discovered in 1930, astronomers proclaimed it the ninth planet, initially thinking it to be Planet X. But in the following decades, Pluto was deemed too small to account for the irregularities, and by the early 1990s, data from the Voyager 2 probe revealed that Neptune had less mass than previously thought, which explained the orbital disturbances without the need for a Planet X.
The search was revived in 2005 when three astronomers, including Mike Brown, a professor of planetary astronomy at the California Institute of Technology, discovered Eris — an icy body slightly larger than Pluto that is also orbiting the sun from the Kuiper Belt.
An artist's concept of the dwarf planet Eris and its moon Dysnomia. The sun is the small star in the distance. - NASA/JPL-Caltech
This discovery eventually led to Pluto’s much-maligned demotion from planet to dwarf planet, and in 2016 Brown and his colleague Konstantin Batygin first published research about their own hypothesis for an additional solar system planet, which they dubbed Planet Nine.
Planet Nine is believed to be between five and 10 times the mass of Earth and would be orbiting the sun far beyond Pluto, at around 550 times the distance between Earth and the sun. Scientists have hypothesized about hidden planets of different dimensions over the years, ranging from a Mars-size body to a “super Pluto.”
Siraj said that the search for Planet Nine or Y is a heated debate in astronomy. “I think it’s a very exciting discussion, and actually that was the motivation for us to investigate the issue, because of all of this debate in the literature,” he said. “I think we’re so lucky to be living at a time when these discoveries might be made.”
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Planet Nine and Planet Y aren’t mutually exclusive, and they could both exist, he said.
Siraj’s Planet Y search started about a year ago when he was trying to find out whether the shape of the Kuiper Belt is flat. “The planets of the solar system have slight tilts up and down, but overall, they kind of almost etch out grooves on a record,” he said, referring to the orbits of the solar system’s planets being on nearly the same plane.
The expectation, he added, is that the icy bodies beyond Neptune should exhibit a similar orientation — “the tabletop should be parallel to the record,” as Siraj puts it — but they don’t.
“It was quite a surprise to find that beyond about 80 times the Earth-sun distance, the solar system suddenly appears to be tilted by about 15 degrees, and this is what sparked the Planet Y hypothesis,” Siraj said. “We started trying to come up with explanations other than a planet that could explain the tilt, but what we found is that you actually need a planet there, because if this was some feature of how the solar system formed, or if it was due to a star flying by, the warp would have gone away by now.”
An illustration of the Kuiper Belt, a region of leftover material from the Solar System's early history that resembles a thick disk and starts beyond the orbit of Neptune. - NASA
Siraj and his coauthors ran computer simulations, which included all the known planets plus a hypothetical one. They kept changing the parameters for the latter and found that previous hypotheses such as Planet Nine didn’t work for their model, and they needed a new one. “Planet Y is most likely a Mercury to Earth-mass body, approximately 100 to 200 times the Earth-sun distance, tilted at least 10 degrees relative to the other planets,” he said.
Clarity in sight
Because the Kuiper Belt is difficult to observe, astronomers rely on studying the orbits of a limited number of objects to infer the presence of a planet. In the case of Siraj’s study, that number is roughly 50, which makes the existence of Planet Y uncertain.
“With these roughly 50 objects, the statistical significance is in the 96% to 98% range,” he said. “It’s strong, but it’s not definitive yet.”
Many more such objects will be discovered once Vera Rubin starts its main mission this fall. Sitting atop a 2,682-meter-tall (8,800-feet-tall) mountain in Chile, the telescope houses the world’s largest digital camera and will image the entire sky every three days.
“It’s really quite a feat of engineering,” Siraj said. “Basically, it will allow us to view a movie of the universe, with each frame existing at a three-day cadence. This is the ideal survey for taking a census of the solar system, because we have to search the entire sky to be able to find distant objects, including additional and yet unseen planets.”
The study is an intriguing approach to probing the subtle warping of the outer solar system, said Batygin, a professor of planetary science at Caltech who has written numerous studies on Planet Nine but did not participate in the Planet Y research. “Over the coming years, the Vera Rubin Observatory will reveal the dynamical structure of the outer solar system with unprecedented clarity,” he said in an email. Once Rubin’s data comes in, astronomers should gain a much sharper picture of whether the Kuiper Belt’s tilt points to additional planets lurking far beyond Neptune.
The Vera C. Rubin Observatory in Cerro Pachon, Chile. - Vera C. Rubin Observatory/Handout/Anadolu Agency/Getty Images
Siraj’s work is a careful analysis of known Kuiper Belt object orbits, looking for patterns in a slightly different way than previous studies, said Samantha Lawler, an associate professor of astronomy at the University of Regina in Saskatchewan. She also was not involved with the recent paper.
The results are interesting but certainly not definitive, Lawler said. “I don’t think that there is good evidence for a fairly large, distant planet that is supposed to be causing the clustering of distant Kuiper Belt orbits,” she said in an email, referring to the Planet Nine theory. “But I think there is promising evidence that there is a smaller body out there that is subtly warping the orbits of some very distant objects.” She agrees that the Rubin telescope will soon discover thousands of new Kuiper Belt objects and test some of these predictions.
The new study is a fascinating look at the distant Kuiper Belt, a region that remains largely unexplored, said Patryk Sofia Lykawka, an associate professor of planetary sciences at Kindai University in Japan. He also didn’t contribute to the Planet Y paper.
“The idea that a Mercury-to-Earth-class planet could be the cause of the said warping is plausible,” he said in an email.
“It adds weight to the hypothesis that there is currently an undiscovered planet lurking in the far outer solar system,” Lykawka added. “Finally, the study demonstrates that it is crucial to conduct surveys of trans-Neptunian objects, particularly in the distant Kuiper Belt, as they hold the key to a deeper understanding of how our entire solar system formed billions of years ago.”
Moon of Saturn could be suitable for life. Scientists found new evidence to confirm it
Eric Lagatta, USA TODAY
Fri, October 3, 2025
The evidence that an ocean-covered moon orbiting around Saturn could support life just got a little stronger.
Enceladus, a small moon harboring a vast ocean beneath its icy surface, has long been considered one of our solar system's best places to search for conditions suitable for extraterrestrial life – and perhaps, even life itself.
Scientists revisiting old data from NASA's Cassini spacecraft, which ended its mission in 2017, have found organic molecules both new and old originating from the icy jets that spew saltwater into space from the surface of Enceladus.
While no life has been found on the 310-mile-wide moon, the discovery confirms that building blocks for it could be present, Nozair Khawaja, a planetary scientist at the Free University of Berlin in Germany, who led the study, said in a press release.
The multi-colored tracks of asteroids flash on and off in this image of two spiral galaxies within the Virgo Cluster. Each of these tracks represents a moving asteroid detected by NSF–DOE Vera C. Rubin Observatory in its first few nights of observations.
The open star cluster Bochum 14 as imaged by NSF–DOE Vera C. Rubin Observatory.
Aerial view of Vera C. Rubin Observatory located in Chile, taken Jan. 24, 2024. Surrounded by desert-like mountains and under the blue skies of northern Chile, the Vera C. Rubin Observatory will revolutionize the study of the universe when it incorporates the largest digital camera ever built in the world. (Photo by) (Photo by JAVIER TORRES/AFP via Getty Images)
Rubin Observatory stands on Cerro Pachón in Chile against a sky full of star trails in this long exposure night sky image.
Sunset at Rubin Observatory on Cerro Pachón in Chile.
NSF–DOE Vera C. Rubin Observatory atop Cerro Pachón in Chile is outlined against the full Moon rising above the horizon. A trick of perspective has enlarged the Moon beyond the size we’d naturally see it on Earth. Rubin Observatory will begin science operations in late 2025.
This image captures not only Vera C. Rubin Observatory, but one of the celestial specimens Rubin Observatory will observe when it comes online: the Milky Way. The bright halo of gas and stars on the left side of the image highlights the very center of the Milky Way galaxy. The dark path that cuts through this center is known as the Great Rift, because it gives the appearance that the Milky Way has been split in half, right through its center and along its radial arms.
This image combines 678 separate images taken by NSF–DOE Vera C. Rubin Observatory in just over seven hours of observing time. Combining many images in this way clearly reveals otherwise faint or invisible details, such as the clouds of gas and dust that comprise the Trifid nebula (top) and the Lagoon nebula, which are several thousand light-years away from Earth.
This image captures a small section of NSF–DOE Vera C. Rubin Observatory’s view of the Virgo Cluster, offering a vivid glimpse of the variety in the cosmos. Visible are two prominent spiral galaxies, three merging galaxies, galaxy groups both near and distant, stars within our own Milky Way, and much more.
Made from over 1100 images captured by NSF-DOE Vera C. Rubin Observatory, this image contains an immense variety of objects. This includes about 10 million galaxies, roughly .05% of the approximately 20 billion galaxies Rubin Observatory will capture in the next decade.
This image captures a small section of NSF–DOE Vera C. Rubin Observatory’s view of the Virgo Cluster, revealing both the grand scale and the faint details of this dynamic region of the cosmos. Bright stars from our own Milky Way shine in the foreground, while a sea of distant reddish galaxies speckle the background.
Here's everything to know about Enceladus, the new discovery and the search for life beyond Earth.
What is Saturn’s moon Enceladus?
Saturn's ocean-bearing moon Enceladus taken in visible light with the Cassini spacecraft narrow-angle camera on Nov. 27, 2016.
While a few worlds in the Milky Way are believed to have liquid water hiding beneath a frozen surface, Enceladus isn't quite as secretive about its subterranean ocean.
The small, icy world is home to water-spouting geysers that spew vapor and ice particles into space – offering a tangible clue to its subsurface saltwater ocean. From samples that various spacecraft have collected, scientists have determined that Enceladus has most of the chemical ingredients required for life, according to NASA.
Though Enceladus is only about as wide as Arizona, the world is named after a giant in Greek mythology. The surface of the moon is notably smooth, white and reflective, with a surface temperature that extremely cold – about negative 330 degrees Fahrenheit.
Scientists find moon has conditions to support life
Because the planet is so cold, most of the material it spews out falls like snow back to the moon’s surface. Some of it, though, remains in space to help form Saturn's E-ring – the second outermost of Saturn's rings – which is where scientists turn to gather observations on Enceladus’ ocean.
While scientists have found evidence of organic molecules in the E-ring before, the team of researchers turned to observations made by NASA’s Cassini spacecraft in 2008 during a close flyby of Enceladus. The probe, which launched in 1997, spent years studying Saturn's icy moons before it was deliberately plunged into Saturn in 2017, ending its mission.
During the flyby, icy grains stuck to the spacecraft before they were altered by space radiation in the E-ring. Within those grains, Khawaja and his team found not just frozen water, but the same organic molecules observed in the E-ring.
Other organic molecules not previously detected were also found that, on Earth, lead to life's building blocks.
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The findings, the team said, strengthen the case for Enceladus being habitable – though they are not claiming to have found evidence of life itself. Rather, the researchers claim the evidence they found warrants follow-up missions to the moon to search for signs of life.
The findings were published Wednesday, Oct. 1, in the journal Nature Astronomy.
How many moons does Saturn have? Mimas also has water
Saturn's system is positively teeming with moons, where Enceladus is one of 274 natural satellites orbiting the ringed planet. A whopping 128 of those were just discovered in March 2025.
The moons range from planet-sized Titan to smaller oddities, some of which are strangely shaped like potatoes or ravioli.
In fact, Enceladus isn't even the only one potentially home to water.
In 2024, a French team of researchers found evidence of a vast liquid ocean beneath the icy exterior of Mimas. The revelation means life could possibly exist on a tiny world paradoxically nicknamed "the Death Star" – a moniker due to the crater on its surface that lends it the look of the planet-killing weapon from "Star Wars."
NASA, meanwhile, has also sent an uncrewed spacecraft to another planet's moon to hunt for signs of habitability. The Europa Clipper spacecraft is due to reach Jupiter's moon of the same name in 2030 and begin conducting flybys to observe the icy world, where water is believed to exist beneath the surface.
Eric Lagatta is the Space Connect reporter for the USA TODAY Network. Reach him at elagatta@gannett.com
This article originally appeared on USA TODAY: Study strengthens case that life could thrive on Saturn's moon Enceladus
Supercomputers unlock secrets of Enceladus’ icy plumes and hidden ocean
Joshua Shavit
Fri, October 3, 2025
Saturn's icy moon Enceladus loses ice mass to space by cryovolcanic geyers, and new TACC supercomputer simulations have improved estimates of ice mass loss. (CREDIT: UT Austin)
It was in the 17th century that Christiaan Huygens and Giovanni Cassini first revealed Saturn’s stunning rings, changing the way people understood the distant planet. Hundreds of years later, NASA’s Cassini mission made a return trip to the Saturn system and came back with even more astounding results. Among them was the finding that one of Saturn’s smaller moons, Enceladus, was far from dormant.
This tiny world, just 313 miles across, shoots enormous plumes of water vapor and ice into space through cracks in its south pole. Those fountains, known as “tiger stripes,” create a thin atmosphere around the moon and supply Saturn’s faint E ring. More importantly, they provide a direct connection to an ocean beneath Enceladus’ ice shell—an environment that could, in theory, support life.
Now scientists are using cutting-edge computer simulations to find out more about how these plumes work, how much material makes it out into space, and what this can tell us about the world beneath the ice.
Arnaud Mahieux, the Royal Belgian Institute for Space Aeronomy and UT Austin
Simulating the Plumes
The new research was led by Aurélien Mahieux of the Royal Belgian Institute for Space Aeronomy and the University of Texas at Austin. His team turned to a technique called Direct Simulation Monte Carlo (DSMC), which tracks what becomes of billions of virtual particles as they travel and collide with one another on their path upward from the vents into the vacuum of space.
“DSMC simulations are very expensive,” Mahieux explained. “We used TACC supercomputers in 2015 to obtain parameterizations to reduce computation time from 48 hours at the time to a few milliseconds now.”
The Texas Advanced Computing Center (TACC) provided its Lonestar6 and Stampede3 supercomputers for the researchers to simulate the plumes from the surface up to 10 kilometers in height. That’s where the gas disperses and begins to blend in with Saturn’s E ring.
What the Models Reveal
At about 10 kilometers over Enceladus, the plume is still fairly dense. By replicating conditions at that height, the team created “radial profiles” that describe how temperature, velocity, and density change with distance from the vent. The profiles are readily adaptable, enabling scientists to predict how plumes will act under various vent circumstances.
Enceladus simulations were performed on the Lonestar6 (left) and Stampede3 (right) supercomputers of the Texas Advanced Computing Center, allocated through awards by the University of Texas Research Cyberinfrastructure Portal. (CREDIT: UT Austin)More
The results showed how sensitively the plumes depend on such parameters as vent width and temperature. Wider vents produce wider plumes, and hotter vents eject gas more rapidly. Even small changes in these parameters have a dramatic effect on the density and shape of the jets.
At higher altitudes, collisions between molecules become rare. Here, the plume forms a cone shape, becoming more tenuous as it gets dispersed into space. The models matched well with features Cassini observed during its many flybys, such as the particle density distributions, giving scientists confidence in their approach.
Reverse Engineering the Vents
One of the most robust parts of the research was a “sensitivity analysis.” The south pole of Enceladus has 98 active geyser sources with slightly different sizes and output. The simulations showed that certain properties, like vent width and mass flow rate, have a particularly strong influence in regulating the plumes.
That means spacecraft measurements of plume density or velocity can be used to work backward and infer what’s happening at the vents themselves. This “inverse modeling” links Cassini’s observations to the underground processes driving the eruptions. Mahieux’s team even narrowed down likely vent temperatures and flow rates, ruling out ranges that didn’t match Cassini’s readings.
South polar view of the mean correlation of the vent parameters to the Ion and Neutral Mass Spectrometer E14 observation geometry, where each symbolrepresents the position of the vents reported by Porco et al. (2014), and the color code is the mean correlation value (see color bar). (CREDIT: Journal of Geophysical Research Planets)More
“Our main finding in this new research is that for 100 cryovolcanic sources, we could constrain the mass flow rates and additional parameters that were not deduced before, such as the temperature at which the material was being ejected,” Mahieux said. “It’s a big step forward in understanding what’s happening at Enceladus.”
Surprisingly, the team found that Enceladus loses 20 to 40 percent less material to space than had been previously calculated in research. These new calculations sharpen estimates of the moon’s ocean interacting with the surface and how long this activity might be sustained.
Building Tools for the Next Missions
One of the primary advantages of using Mahieux’s work is that the models are not theoretical alone—they can be turned into rapid, functional tools for mission planning. Rather than needing to conduct long, resource-draining simulations, scientists can now generate predictions in a few seconds.
This is especially important for future missions that will try to sample the plumes or even land on Enceladus. Knowing the expected density and velocity of particles, engineers can develop instruments that won’t be overwhelmed and plan safe spacecraft trajectories.
Co-author David Goldstein at UT Austin created the DSMC code called Planet in 2011. His earlier work made these advances possible. Thanks to TACC’s high-performance computers, the simulations can now handle realistic pressure and much larger areas than could be done on desktop computers.
Results of the fits of the Ion and Neutral Mass Spectrometer E3, E5, E7, E14, E17, E18, and the Ultraviolet Imaging Spectrograph solar occultation. In eachpanel, the black curve is the observation, and the blue curve is the best fit, the width of which represents the uncertainty. (CREDIT: Journal of Geophysical Research Planets)More
A Window Into Hidden Oceans
The interest in Enceladus is owed to more than its spectacular geysers. Scientists are convinced that beneath its icy crust lies an ocean of liquid water globally. The plumes offer a distinct chance to explore that ocean without needing to drill through miles of ice
“There is an ocean of liquid water under these ‘big balls of ice,'” Mahieux said, referring not only to Enceladus but also to Jupiter, Uranus, and Neptune moons. “The plumes at Enceladus are a window to the conditions below.”
Future NASA or European Space Agency missions could use these models to determine where and how to sample the plumes for organic molecules, salts, or other signs of habitability. Some concepts take it even further, proposing landers that one day could explore the ocean itself.
“Supercomputers can give us answers to questions that we could not even dream of asking 10 or 15 years ago,” Mahieux said. “We can now come much closer to simulating what nature is doing.”
Comparison of the mean mass flow rates for all observations and with data from the literature. (CREDIT: Journal of Geophysical Research Planets)
Practical Implications of the Research
This research goes beyond satisfying curiosity about a distant moon. The new simulations give scientists a roadmap for studying hidden oceans in icy moons across the solar system.
By knowing how plume material disperses and expands, spacecraft designers can craft superior ships, safer flybys, and more effective sampling instruments. These enhancements could increase the likelihood of detecting chemical evidence of extraterrestrial life.
For humans, the find is a reminder that Earth may not be the only world with conditions to support life. The icy moons of gas giants are maybe the holders of one of science’s biggest questions: Are we alone?
Eric Lagatta, USA TODAY
Fri, October 3, 2025
The evidence that an ocean-covered moon orbiting around Saturn could support life just got a little stronger.
Enceladus, a small moon harboring a vast ocean beneath its icy surface, has long been considered one of our solar system's best places to search for conditions suitable for extraterrestrial life – and perhaps, even life itself.
Scientists revisiting old data from NASA's Cassini spacecraft, which ended its mission in 2017, have found organic molecules both new and old originating from the icy jets that spew saltwater into space from the surface of Enceladus.
While no life has been found on the 310-mile-wide moon, the discovery confirms that building blocks for it could be present, Nozair Khawaja, a planetary scientist at the Free University of Berlin in Germany, who led the study, said in a press release.
The multi-colored tracks of asteroids flash on and off in this image of two spiral galaxies within the Virgo Cluster. Each of these tracks represents a moving asteroid detected by NSF–DOE Vera C. Rubin Observatory in its first few nights of observations.
The open star cluster Bochum 14 as imaged by NSF–DOE Vera C. Rubin Observatory.
Aerial view of Vera C. Rubin Observatory located in Chile, taken Jan. 24, 2024. Surrounded by desert-like mountains and under the blue skies of northern Chile, the Vera C. Rubin Observatory will revolutionize the study of the universe when it incorporates the largest digital camera ever built in the world. (Photo by) (Photo by JAVIER TORRES/AFP via Getty Images)
Rubin Observatory stands on Cerro Pachón in Chile against a sky full of star trails in this long exposure night sky image.
Sunset at Rubin Observatory on Cerro Pachón in Chile.
NSF–DOE Vera C. Rubin Observatory atop Cerro Pachón in Chile is outlined against the full Moon rising above the horizon. A trick of perspective has enlarged the Moon beyond the size we’d naturally see it on Earth. Rubin Observatory will begin science operations in late 2025.
This image captures not only Vera C. Rubin Observatory, but one of the celestial specimens Rubin Observatory will observe when it comes online: the Milky Way. The bright halo of gas and stars on the left side of the image highlights the very center of the Milky Way galaxy. The dark path that cuts through this center is known as the Great Rift, because it gives the appearance that the Milky Way has been split in half, right through its center and along its radial arms.
This image combines 678 separate images taken by NSF–DOE Vera C. Rubin Observatory in just over seven hours of observing time. Combining many images in this way clearly reveals otherwise faint or invisible details, such as the clouds of gas and dust that comprise the Trifid nebula (top) and the Lagoon nebula, which are several thousand light-years away from Earth.
This image captures a small section of NSF–DOE Vera C. Rubin Observatory’s view of the Virgo Cluster, offering a vivid glimpse of the variety in the cosmos. Visible are two prominent spiral galaxies, three merging galaxies, galaxy groups both near and distant, stars within our own Milky Way, and much more.
Made from over 1100 images captured by NSF-DOE Vera C. Rubin Observatory, this image contains an immense variety of objects. This includes about 10 million galaxies, roughly .05% of the approximately 20 billion galaxies Rubin Observatory will capture in the next decade.
This image captures a small section of NSF–DOE Vera C. Rubin Observatory’s view of the Virgo Cluster, revealing both the grand scale and the faint details of this dynamic region of the cosmos. Bright stars from our own Milky Way shine in the foreground, while a sea of distant reddish galaxies speckle the background.
Here's everything to know about Enceladus, the new discovery and the search for life beyond Earth.
What is Saturn’s moon Enceladus?
Saturn's ocean-bearing moon Enceladus taken in visible light with the Cassini spacecraft narrow-angle camera on Nov. 27, 2016.
While a few worlds in the Milky Way are believed to have liquid water hiding beneath a frozen surface, Enceladus isn't quite as secretive about its subterranean ocean.
The small, icy world is home to water-spouting geysers that spew vapor and ice particles into space – offering a tangible clue to its subsurface saltwater ocean. From samples that various spacecraft have collected, scientists have determined that Enceladus has most of the chemical ingredients required for life, according to NASA.
Though Enceladus is only about as wide as Arizona, the world is named after a giant in Greek mythology. The surface of the moon is notably smooth, white and reflective, with a surface temperature that extremely cold – about negative 330 degrees Fahrenheit.
Scientists find moon has conditions to support life
Because the planet is so cold, most of the material it spews out falls like snow back to the moon’s surface. Some of it, though, remains in space to help form Saturn's E-ring – the second outermost of Saturn's rings – which is where scientists turn to gather observations on Enceladus’ ocean.
While scientists have found evidence of organic molecules in the E-ring before, the team of researchers turned to observations made by NASA’s Cassini spacecraft in 2008 during a close flyby of Enceladus. The probe, which launched in 1997, spent years studying Saturn's icy moons before it was deliberately plunged into Saturn in 2017, ending its mission.
During the flyby, icy grains stuck to the spacecraft before they were altered by space radiation in the E-ring. Within those grains, Khawaja and his team found not just frozen water, but the same organic molecules observed in the E-ring.
Other organic molecules not previously detected were also found that, on Earth, lead to life's building blocks.
Astrophotographers capture new views of Comet C/2025 A6 (Lemmon)
Earth is getting darker and it’s changing the planet’s climate balance
The findings, the team said, strengthen the case for Enceladus being habitable – though they are not claiming to have found evidence of life itself. Rather, the researchers claim the evidence they found warrants follow-up missions to the moon to search for signs of life.
The findings were published Wednesday, Oct. 1, in the journal Nature Astronomy.
How many moons does Saturn have? Mimas also has water
Saturn's system is positively teeming with moons, where Enceladus is one of 274 natural satellites orbiting the ringed planet. A whopping 128 of those were just discovered in March 2025.
The moons range from planet-sized Titan to smaller oddities, some of which are strangely shaped like potatoes or ravioli.
In fact, Enceladus isn't even the only one potentially home to water.
In 2024, a French team of researchers found evidence of a vast liquid ocean beneath the icy exterior of Mimas. The revelation means life could possibly exist on a tiny world paradoxically nicknamed "the Death Star" – a moniker due to the crater on its surface that lends it the look of the planet-killing weapon from "Star Wars."
NASA, meanwhile, has also sent an uncrewed spacecraft to another planet's moon to hunt for signs of habitability. The Europa Clipper spacecraft is due to reach Jupiter's moon of the same name in 2030 and begin conducting flybys to observe the icy world, where water is believed to exist beneath the surface.
Eric Lagatta is the Space Connect reporter for the USA TODAY Network. Reach him at elagatta@gannett.com
This article originally appeared on USA TODAY: Study strengthens case that life could thrive on Saturn's moon Enceladus
Supercomputers unlock secrets of Enceladus’ icy plumes and hidden ocean
Joshua Shavit
Fri, October 3, 2025
Saturn's icy moon Enceladus loses ice mass to space by cryovolcanic geyers, and new TACC supercomputer simulations have improved estimates of ice mass loss. (CREDIT: UT Austin)
It was in the 17th century that Christiaan Huygens and Giovanni Cassini first revealed Saturn’s stunning rings, changing the way people understood the distant planet. Hundreds of years later, NASA’s Cassini mission made a return trip to the Saturn system and came back with even more astounding results. Among them was the finding that one of Saturn’s smaller moons, Enceladus, was far from dormant.
This tiny world, just 313 miles across, shoots enormous plumes of water vapor and ice into space through cracks in its south pole. Those fountains, known as “tiger stripes,” create a thin atmosphere around the moon and supply Saturn’s faint E ring. More importantly, they provide a direct connection to an ocean beneath Enceladus’ ice shell—an environment that could, in theory, support life.
Now scientists are using cutting-edge computer simulations to find out more about how these plumes work, how much material makes it out into space, and what this can tell us about the world beneath the ice.
Arnaud Mahieux, the Royal Belgian Institute for Space Aeronomy and UT Austin
. (CREDIT: UT Austin)
Simulating the Plumes
The new research was led by Aurélien Mahieux of the Royal Belgian Institute for Space Aeronomy and the University of Texas at Austin. His team turned to a technique called Direct Simulation Monte Carlo (DSMC), which tracks what becomes of billions of virtual particles as they travel and collide with one another on their path upward from the vents into the vacuum of space.
“DSMC simulations are very expensive,” Mahieux explained. “We used TACC supercomputers in 2015 to obtain parameterizations to reduce computation time from 48 hours at the time to a few milliseconds now.”
The Texas Advanced Computing Center (TACC) provided its Lonestar6 and Stampede3 supercomputers for the researchers to simulate the plumes from the surface up to 10 kilometers in height. That’s where the gas disperses and begins to blend in with Saturn’s E ring.
What the Models Reveal
At about 10 kilometers over Enceladus, the plume is still fairly dense. By replicating conditions at that height, the team created “radial profiles” that describe how temperature, velocity, and density change with distance from the vent. The profiles are readily adaptable, enabling scientists to predict how plumes will act under various vent circumstances.
Enceladus simulations were performed on the Lonestar6 (left) and Stampede3 (right) supercomputers of the Texas Advanced Computing Center, allocated through awards by the University of Texas Research Cyberinfrastructure Portal. (CREDIT: UT Austin)More
The results showed how sensitively the plumes depend on such parameters as vent width and temperature. Wider vents produce wider plumes, and hotter vents eject gas more rapidly. Even small changes in these parameters have a dramatic effect on the density and shape of the jets.
At higher altitudes, collisions between molecules become rare. Here, the plume forms a cone shape, becoming more tenuous as it gets dispersed into space. The models matched well with features Cassini observed during its many flybys, such as the particle density distributions, giving scientists confidence in their approach.
Reverse Engineering the Vents
One of the most robust parts of the research was a “sensitivity analysis.” The south pole of Enceladus has 98 active geyser sources with slightly different sizes and output. The simulations showed that certain properties, like vent width and mass flow rate, have a particularly strong influence in regulating the plumes.
That means spacecraft measurements of plume density or velocity can be used to work backward and infer what’s happening at the vents themselves. This “inverse modeling” links Cassini’s observations to the underground processes driving the eruptions. Mahieux’s team even narrowed down likely vent temperatures and flow rates, ruling out ranges that didn’t match Cassini’s readings.
South polar view of the mean correlation of the vent parameters to the Ion and Neutral Mass Spectrometer E14 observation geometry, where each symbolrepresents the position of the vents reported by Porco et al. (2014), and the color code is the mean correlation value (see color bar). (CREDIT: Journal of Geophysical Research Planets)More
“Our main finding in this new research is that for 100 cryovolcanic sources, we could constrain the mass flow rates and additional parameters that were not deduced before, such as the temperature at which the material was being ejected,” Mahieux said. “It’s a big step forward in understanding what’s happening at Enceladus.”
Surprisingly, the team found that Enceladus loses 20 to 40 percent less material to space than had been previously calculated in research. These new calculations sharpen estimates of the moon’s ocean interacting with the surface and how long this activity might be sustained.
Building Tools for the Next Missions
One of the primary advantages of using Mahieux’s work is that the models are not theoretical alone—they can be turned into rapid, functional tools for mission planning. Rather than needing to conduct long, resource-draining simulations, scientists can now generate predictions in a few seconds.
This is especially important for future missions that will try to sample the plumes or even land on Enceladus. Knowing the expected density and velocity of particles, engineers can develop instruments that won’t be overwhelmed and plan safe spacecraft trajectories.
Co-author David Goldstein at UT Austin created the DSMC code called Planet in 2011. His earlier work made these advances possible. Thanks to TACC’s high-performance computers, the simulations can now handle realistic pressure and much larger areas than could be done on desktop computers.
Results of the fits of the Ion and Neutral Mass Spectrometer E3, E5, E7, E14, E17, E18, and the Ultraviolet Imaging Spectrograph solar occultation. In eachpanel, the black curve is the observation, and the blue curve is the best fit, the width of which represents the uncertainty. (CREDIT: Journal of Geophysical Research Planets)More
A Window Into Hidden Oceans
The interest in Enceladus is owed to more than its spectacular geysers. Scientists are convinced that beneath its icy crust lies an ocean of liquid water globally. The plumes offer a distinct chance to explore that ocean without needing to drill through miles of ice
“There is an ocean of liquid water under these ‘big balls of ice,'” Mahieux said, referring not only to Enceladus but also to Jupiter, Uranus, and Neptune moons. “The plumes at Enceladus are a window to the conditions below.”
Future NASA or European Space Agency missions could use these models to determine where and how to sample the plumes for organic molecules, salts, or other signs of habitability. Some concepts take it even further, proposing landers that one day could explore the ocean itself.
“Supercomputers can give us answers to questions that we could not even dream of asking 10 or 15 years ago,” Mahieux said. “We can now come much closer to simulating what nature is doing.”
Comparison of the mean mass flow rates for all observations and with data from the literature. (CREDIT: Journal of Geophysical Research Planets)
Practical Implications of the Research
This research goes beyond satisfying curiosity about a distant moon. The new simulations give scientists a roadmap for studying hidden oceans in icy moons across the solar system.
By knowing how plume material disperses and expands, spacecraft designers can craft superior ships, safer flybys, and more effective sampling instruments. These enhancements could increase the likelihood of detecting chemical evidence of extraterrestrial life.
For humans, the find is a reminder that Earth may not be the only world with conditions to support life. The icy moons of gas giants are maybe the holders of one of science’s biggest questions: Are we alone?
Rich Smith, The Motley Fool
Sat, October 4, 2025
Key Points
NASA awarded Sierra Space's parent company part of a $14 billion ISS supply contract in 2016.
Nearly 10 years later, everyone on that contract but Sierra Space is doing supply runs to ISS.
Last week, NASA told Sierra Space it must test-fly Dream Chaser in 2026 or lose its contract.
"Sierra Space Corporation."
It's been a couple of years since I last had an opportunity to write about this space stock. Back in 2023, the privately held company raised $290 million in new funds to complete development of its Dream Chaser spacecraft -- and surged ahead to a $5 billion private market valuation, making Sierra Space 5X a unicorn stock
And at long last, Sierra Space is back in the news this week. But not in a good way.
Image source: Sierra Space.
Playing ketchup in space
Remember the old Heinz ketchup commercial, the one singing "an-ti-ci-pation, an-tic-i-pay-yay-shun," as the kid waited for his ketchup to pour out of the bottle.
For space investors, that's what it's felt like waiting for Sierra Space to do something interesting these last several years. It's been nearly a decade since NASA awarded Sierra Space (technically, its parent company Sierra Nevada Corp.) a role in its $14 billion CRS-2 project to send Commercial Re-Supply spacecraft to the International Space Station (ISS).
Valued at roughly $628 million per launch, and with Sierra expected to run seven of the launches, the contract felt like a windfall for Sierra Space, which was a surprise winner added to the list of two incumbent CRS-1 providers, SpaceX and Northrop Grumman (known as Orbital ATK at the time).
Through 2024, the three companies were hired to launch a total of 18 CRS missions to keep the ISS astronauts well-stocked with supplies. SpaceX would use its Dragon spacecraft for its launches, and Northrop its Cygnus supply vessel. Sierra, the new entrant to the CRS club, was chosen on the strength of the new Dream Chaser spaceplane it was designing, which was expected to start launching in 2019.
Problem is, it's 2025 today -- and Dream Chaser hasn't flown even once.
Sierra was making NASA wait
And NASA's patience with Sierra Space has finally worn thin. We had warnings that things were not looking great for Sierra back in 2022, when NASA extended its existing CRS-2 contract from the original 18 launches to 32, running through 2026. In that extension, NASA specifically named SpaceX to conduct 15 of the launches, Northrop 14, and Sierra... only three.
Last week, the space agency announced it has decided to "modify" the contract even further. And by "modify" I mean it's probably going to kick Sierra out of the contract entirely.
Admittedly, NASA put it kindlier than that: "After a thorough evaluation, NASA and Sierra Space have mutually agreed to modify the contract, as the company determined Dream Chaser development is best served by a free flight demonstration, targeted in late 2026."
That's how NASA phrased its ultimatum -- but the meaning is clear.
After 10 years of no Dream Chaser flights, NASA's tired of waiting for Sierra's phantom spacecraft. Now, NASA's telling the company it needs to either prove Dream Chaser can fly, after which NASA might permit it to fly to ISS and pay for the flights -- or else admit Dream Chaser is a mirage and let SpaceX and Northrop handle the work of resupplying the space station. In the meantime, NASA's shutting off the funding spigot to Sierra, promising to provide only "minimal support through the remainder of the development and the flight demonstration."
Furthermore, even if Sierra does get Dream Chaser to orbit by next year, "NASA is no longer obligated [to buy] a specific number of resupply missions," and only "may order Dream Chaser resupply flights to the space station" (emphasis added -- "may," not "will").
Time is running out for Sierra Space -- and for a Sierra Space IPO
You can understand NASA's frustration. ISS is due to deorbit in 2030. (NASA's even paying Elon Musk $850 million to make it so). If Sierra doesn't get Dream Chaser operational soon, there's not going to be an ISS to deliver supplies to anymore. And in any case, SpaceX and Northrop appear to have the situation well in hand, such that there's not really any need for Sierra Space's Dream Chaser spacecraft to lend a hand.
Granted, there's still the possibility Dream Chaser could be used for flights to one or more future private space stations that will eventually replace ISS. That's probably part of the reason (some) investors still hope we will see Sierra Space announce an IPO one day.
