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By NASA
NASA’s Dawn spacecraft captured this image of Vesta as it left the giant asteroid’s orbit in 2012. The framing camera was looking down at the north pole, which is in the middle of the image.NASA/JPL-Caltech/UCLA/MPS/DLR/IDA Known as flow formations, these channels could be etched on bodies that would seem inhospitable to liquid because they are exposed to the extreme vacuum conditions of space.
Pocked with craters, the surfaces of many celestial bodies in our solar system provide clear evidence of a 4.6-billion-year battering by meteoroids and other space debris. But on some worlds, including the giant asteroid Vesta that NASA’s Dawn mission explored, the surfaces also contain deep channels, or gullies, whose origins are not fully understood.
A prime hypothesis holds that they formed from dry debris flows driven by geophysical processes, such as meteoroid impacts, and changes in temperature due to Sun exposure. A recent NASA-funded study, however, provides some evidence that impacts on Vesta may have triggered a less-obvious geologic process: sudden and brief flows of water that carved gullies and deposited fans of sediment. By using lab equipment to mimic conditions on Vesta, the study, which appeared in Planetary Science Journal, detailed for the first time what the liquid could be made of and how long it would flow before freezing.
Although the existence of frozen brine deposits on Vesta is unconfirmed, scientists have previously hypothesized that meteoroid impacts could have exposed and melted ice that lay under the surface of worlds like Vesta. In that scenario, flows resulting from this process could have etched gullies and other surface features that resemble those on Earth.
To explore potential explanations for deep channels, or gullies, seen on Vesta, scientists used JPL’s Dirty Under-vacuum Simulation Testbed for Icy Environments, or DUSTIE, to simulate conditions on the giant asteroid that would occur after meteoroids strike the surface.NASA/JPL-Caltech But how could airless worlds — celestial bodies without atmospheres and exposed to the intense vacuum of space — host liquids on the surface long enough for them to flow? Such a process would run contrary to the understanding that liquids quickly destabilize in a vacuum, changing to a gas when the pressure drops.
“Not only do impacts trigger a flow of liquid on the surface, the liquids are active long enough to create specific surface features,” said project leader and planetary scientist Jennifer Scully of NASA’s Jet Propulsion Laboratory in Southern California, where the experiments were conducted. “But for how long? Most liquids become unstable quickly on these airless bodies, where the vacuum of space is unyielding.”
The critical component turns out to be sodium chloride — table salt. The experiments found that in conditions like those on Vesta, pure water froze almost instantly, while briny liquids stayed fluid for at least an hour. “That’s long enough to form the flow-associated features identified on Vesta, which were estimated to require up to a half-hour,” said lead author Michael J. Poston of the Southwest Research Institute in San Antonio.
Launched in 2007, the Dawn spacecraft traveled to the main asteroid belt between Mars and Jupiter to orbit Vesta for 14 months and Ceres for almost four years. Before ending in 2018, the mission uncovered evidence that Ceres had been home to a subsurface reservoir of brine and may still be transferring brines from its interior to the surface. The recent research offers insights into processes on Ceres but focuses on Vesta, where ice and salts may produce briny liquid when heated by an impact, scientists said.
Re-creating Vesta
To re-create Vesta-like conditions that would occur after a meteoroid impact, the scientists relied on a test chamber at JPL called the Dirty Under-vacuum Simulation Testbed for Icy Environments, or DUSTIE. By rapidly reducing the air pressure surrounding samples of liquid, they mimicked the environment around fluid that comes to the surface. Exposed to vacuum conditions, pure water froze instantly. But salty fluids hung around longer, continuing to flow before freezing.
The brines they experimented with were a little over an inch (a few centimeters) deep; scientists concluded the flows on Vesta that are yards to tens of yards deep would take even longer to refreeze.
The researchers were also able to re-create the “lids” of frozen material thought to form on brines. Essentially a frozen top layer, the lids stabilize the liquid beneath them, protecting it from being exposed to the vacuum of space — or, in this case the vacuum of the DUSTIE chamber — and helping the liquid flow longer before freezing again.
This phenomenon is similar to how on Earth lava flows farther in lava tubes than when exposed to cool surface temperatures. It also matches up with modeling research conducted around potential mud volcanoes on Mars and volcanoes that may have spewed icy material from volcanoes on Jupiter’s moon Europa.
“Our results contribute to a growing body of work that uses lab experiments to understand how long liquids last on a variety of worlds,” Scully said.
Find more information about NASA’s Dawn mission here:
https://science.nasa.gov/mission/dawn/
News Media Contacts
Gretchen McCartney
Jet Propulsion Laboratory, Pasadena, Calif.
818-287-4115
gretchen.p.mccartney@jpl.nasa.gov
Karen Fox / Molly Wasser
NASA Headquarters, Washington
202-358-1600
karen.c.fox@nasa.gov / molly.l.wasser@nasa.gov
2024-178
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Last Updated Dec 20, 2024 Related Terms
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By NASA
2 Min Read NASA Astronauts Compete in ISS “Olympics”
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The International Space Station Olympics.NASA See the Content Online: Olympics Instagram | Olympics X | Olympics Website | NASA HQ YouTube | NASA Facebook | FLOTUS Instagram
“Over the past few days on the International Space Station, we’ve had an absolute blast pretending to be Olympic athletes,” astronaut Matt Dominick started off in a crew message. “We, of course, have had the benefits of weightlessness…We can’t imagine how hard this must be, to be such a world-class athlete doing your sports under actual gravity. So from all of us aboard the International Space Station to every single athlete in the Olympic Games, Godspeed!”
250 miles above Earth, NASA astronauts aboard the International Space Station (ISS) held their own version of the 2024 Summer Olympics. Before the athletes competed on the ground in Paris, astronauts Matthew Dominick, Suni Williams, Butch Wilmore, Jeanette Epps, Tracy Dyson, and Mike Barratt brought the spirit of the Games to space, showcasing their own unique series of sports.
The two-minute epic montage, released on July 26, begins with crew members passing a uniquely orbital Olympic torch, crafted right aboard the space station. Each astronaut warms up for their event, with a standout moment featuring Butch Wilmore taking a sip from a floating sphere of water.
Let the games begin!
NASA astronaut Tracy Dyson kicked things off by powerlifting two of her fellow astronauts. Then Jeanette Epps went for the gold in the long jump. Matthew Dominick defied microgravity, executing a flawless gymnastics routine as he flew through the station. Suni Williams showcased her focus and strength, becoming the first to compete on the pommel horse in space. Mike Barratt gave it his all in the discus. And finally, Butch Wilmore set a record with his shotput throw!
NASA astronaut Tracy C. Dyson powerlifts two of her fellow astronauts during the ISS “Olympics.”NASA NASA astronaut Jeanette Epps goes for the gold in her long jump for the ISS “Olympics.”NASA NASA astronaut Matt Dominick defies microgravity during his ISS “Olympics” gymnastics routine.NASA NASA astronaut Suni Williams shows off her strength during the ISS “Olympics.”NASA NASA astronaut Mike Barratt performs a discus throw in microgravity for the ISS “Olympics.”NASA NASA astronaut Butch Wilmore throws the shot put during the ISS “Olympics.”NASA The crew ended the video with a heartfelt message to all Olympic athletes, celebrating the spirit of international cooperation—a core principle of space station operations. The video was shared collaboratively across multiple social media channels, amplifying its reach and impact. Both NASA and the official Olympics social media accounts posted the video, showcasing the astronauts’ unique tribute to the Games. A special version of the video was also shared on the First Lady’s Instagram account, further emphasizing the spirit of international unity and the connection between space exploration and global events. This coordinated effort highlighted the collaboration between NASA and the Olympics, bringing attention to the shared values of teamwork, perseverance, and global cooperation.
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Last Updated Dec 05, 2024 Related Terms
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