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By NASA
4 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
A crane lowers the steel reflector framework for Deep Space Station 23 into position Dec. 18 on a 65-foot-high (20-meter) platform above the antenna’s pedestal that will steer the reflector. Panels will be affixed to the structure create a curved surface to collect radio frequency signals.NASA/JPL-Caltech After the steel framework of the Deep Space Station 23 reflector dish was lowered into place on Dec. 18, a crew installed the quadripod, a four-legged support structure that will direct radio frequency signals from deep space that bounce off the main reflector into the antenna’s receiver.NASA/JPL-Caltech Deep Space Station 23’s 133-ton reflector dish was recently installed, marking a key step in strengthening NASA’s Deep Space Network.
NASA’s Deep Space Network, an array of giant radio antennas, allows agency missions to track, send commands to, and receive scientific data from spacecraft venturing to the Moon and beyond. NASA is adding a new antenna, bringing the total to 15, to support increased demand for the world’s largest and most sensitive radio frequency telecommunication system.
Installation of the latest antenna took place on Dec. 18, when teams at NASA’s Goldstone Deep Space Communications Complex near Barstow, California, installed the metal reflector framework for Deep Space Station 23, a multifrequency beam-waveguide antenna. When operational in 2026, Deep Space Station 23 will receive transmissions from missions such as Perseverance, Psyche, Europa Clipper, Voyager 1, and a growing fleet of future human and robotic spacecraft in deep space.
“This addition to the Deep Space Network represents a crucial communication upgrade for the agency,” said Kevin Coggins, deputy associate administrator of NASA’s SCaN (Space Communications and Navigation) program. “The communications infrastructure has been in continuous operation since its creation in 1963, and with this upgrade we are ensuring NASA is ready to support the growing number of missions exploring the Moon, Mars, and beyond.”
This time-lapse video shows the entire day of construction activities for the Deep Space Station 23 antenna at the NASA Deep Space Network’s Goldstone Space Communications Complex near Barstow, California, on Dec. 18. NASA/JPL-Caltech Construction of the new antenna has been under way for more than four years, and during the installation, teams used a crawler crane to lower the 133-ton metal skeleton of the 112-foot-wide (34-meter-wide) parabolic reflector before it was bolted to a 65-foot-high (20-meter-high) alidade, a platform above the antenna’s pedestal that will steer the reflector during operations.
“One of the biggest challenges facing us during the lift was to ensure that 40 bolt-holes were perfectly aligned between the structure and alidade,” said Germaine Aziz, systems engineer, Deep Space Network Aperture Enhancement Program of NASA’s Jet Propulsion Laboratory in Southern California. “This required a meticulous emphasis on alignment prior to the lift to guarantee everything went smoothly on the day.”
Following the main lift, engineers carried out a lighter lift to place a quadripod, a four-legged support structure weighing 16 1/2 tons, onto the center of the upward-facing reflector. The quadripod features a curved subreflector that will direct radio frequency signals from deep space that bounce off the main reflector into the antenna’s pedestal, where the antenna’s receivers are housed.
In the early morning of Dec. 18, a crane looms over the 112-foot-wide (34-meter-wide) steel framework for Deep Space Station 23 reflector dish, which will soon be lowered into position on the antenna’s base structure.NASA/JPL-Caltech Engineers will now work to fit panels onto the steel skeleton to create a curved surface to reflect radio frequency signals. Once complete, Deep Space Station 23 will be the fifth of six new beam-waveguide antennas to join the network, following Deep Space Station 53, which was added at the Deep Space Network’s Madrid complex in 2022.
“With the Deep Space Network, we are able to explore the Martian landscape with our rovers, see the James Webb Space Telescope’s stunning cosmic observations, and so much more,” said Laurie Leshin, director of JPL. “The network enables over 40 deep space missions, including the farthest human-made objects in the universe, Voyager 1 and 2. With upgrades like these, the network will continue to support humanity’s exploration of our solar system and beyond, enabling groundbreaking science and discovery far into the future.”
NASA’s Deep Space Network is managed by JPL, with the oversight of NASA’s SCaN Program. More than 100 NASA and non-NASA missions rely on the Deep Space Network and Near Space Network, including supporting astronauts aboard the International Space Station and future Artemis missions, monitoring Earth’s weather and the effects of climate change, supporting lunar exploration, and uncovering the solar system and beyond.
For more information about the Deep Space Network, visit:
https://www.nasa.gov/communicating-with-missions/dsn
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Ian J. O’Neill
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Last Updated Dec 20, 2024 Related Terms
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4 min read Lab Work Digs Into Gullies Seen on Giant Asteroid Vesta by NASA’s Dawn
Article 8 hours ago 5 min read Avalanches, Icy Explosions, and Dunes: NASA Is Tracking New Year on Mars
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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/
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Gretchen McCartney
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NASA Headquarters, Washington
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Last Updated Dec 20, 2024 Related Terms
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By NASA
5 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
It’s a new year on Mars, and while New Year’s means winter in Earth’s northern hemisphere, it’s the start of spring in the same region of the Red Planet. And that means ice is thawing, leading to all sorts of interesting things. JPL research scientist Serina Diniega explains. NASA/JPL-Caltech Instead of a winter wonderland, the Red Planet’s northern hemisphere goes through an active — even explosive — spring thaw.
While New Year’s Eve is around the corner here on Earth, Mars scientists are ahead of the game: The Red Planet completed a trip around the Sun on Nov. 12, 2024, prompting a few researchers to raise a toast.
But the Martian year, which is 687 Earth days, ends in a very different way in the planet’s northern hemisphere than it does in Earth’s northern hemisphere: While winter’s kicking in here, spring is starting there. That means temperatures are rising and ice is thinning, leading to frost avalanches crashing down cliffsides, carbon dioxide gas exploding from the ground, and powerful winds helping reshape the north pole.
“Springtime on Earth has lots of trickling as water ice gradually melts. But on Mars, everything happens with a bang,” said Serina Diniega, who studies planetary surfaces at NASA’s Jet Propulsion Laboratory in Southern California.
Mars’ wispy atmosphere doesn’t allow liquids to pool on the surface, like on Earth. Instead of melting, ice sublimates, turning directly into a gas. The sudden transition in spring means a lot of violent changes as both water ice and carbon dioxide ice — dry ice, which is much more plentiful on Mars than frozen water — weaken and break.
“You get lots of cracks and explosions instead of melting,” Diniega said. “I imagine it gets really noisy.”
Using the cameras and other sensors aboard NASA’s Mars Reconnaissance Orbiter (MRO), which launched in 2005, scientists study all this activity to improve their understanding of the forces shaping the dynamic Martian surface. Here’s some of what they track.
Frost Avalanches
In 2015, MRO’s High-Resolution Imaging Science Experiment (HiRISE) camera captured a 66-foot-wide (20-meter-wide) chunk of carbon dioxide frost in freefall. Chance observations like this are reminders of just how different Mars is from Earth, Diniega said, especially in springtime, when these surface changes are most noticeable.
Martian spring involves lots of cracking ice, which led to this 66-foot-wide (20-meter-wide) chunk of carbon dioxide frost captured in freefall by the HiRISE camera aboard NASA’s Mars Reconnaissance Orbiter in 2015NASA/JPL-Caltech/University of Arizona “We’re lucky we’ve had a spacecraft like MRO observing Mars for as long as it has,” Diniega said. “Watching for almost 20 years has let us catch dramatic moments like these avalanches.”
Gas Geysers
Diniega has relied on HiRISE to study another quirk of Martian springtime: gas geysers that blast out of the surface, throwing out dark fans of sand and dust. These explosive jets form due to energetic sublimation of carbon dioxide ice. As sunlight shines through the ice, its bottom layers turn to gas, building pressure until it bursts into the air, creating those dark fans of material.
As light shines through carbon dioxide ice on Mars, it heats up its bottom layers, which, rather than melting into a liquid, turn into gas. The buildup gas eventually results in explosive geysers that toss dark fans of debris on to the surface.light shines through carbon dioxide ice on Mars But to see the best examples of the newest fans, researchers will have to wait until December 2025, when spring starts in the southern hemisphere. There, the fans are bigger and more clearly defined.
Spiders
Another difference between ice-related action in the two hemispheres: Once all the ice around some northern geysers has sublimated in summer, what’s left behind in the dirt are scour marks that, from space, look like giant spider legs. Researchers recently re-created this process in a JPL lab.
Sometimes, after carbon dioxide geysers have erupted from ice-covered areas on Mars, they leave scour marks on the surface. When the ice is all gone by summer, these long scour marks look like the legs of giant spiders.NASA/JPL-Caltech/University of Arizona Powerful Winds
For Isaac Smith of Toronto’s York University, one of the most fascinating subjects in springtime is the Texas-size ice cap at Mars’ north pole. Etched into the icy dome are swirling troughs, revealing traces of the red surface below. The effect is like a swirl of milk in a café latte.
“These things are enormous,” Smith said, noting that some are a long as California. “You can find similar troughs in Antarctica but nothing at this scale.”
As temperatures rise, powerful winds kick up that carve deep troughs into the ice cap of Mars’ north pole. Some of these troughs are as long as California, and give the Martian north pole its trademark swirls. This image was captured by NASA’s now-inactive Mars Global Surveyor.NASA/JPL-Caltech/MSSS Fast, warm wind has carved the spiral shapes over eons, and the troughs act as channels for springtime wind gusts that become more powerful as ice at the north pole starts to thaw. Just like the Santa Ana winds in Southern California or the Chinook winds in the Rocky Mountains, these gusts pick up speed and temperature as they ride down the troughs — what’s called an adiabatic process.
Wandering Dunes
The winds that carve the north pole’s troughs also reshape Mars’ sand dunes, causing sand to pile up on one side while removing sand from the other side. Over time, the process causes dunes to migrate, just as it does with dunes on Earth.
This past September, Smith coauthored a paper detailing how carbon dioxide frost settles on top of polar sand dunes during winter, freezing them in place. When the frost all thaws away in the spring, the dunes begin migrating again.
Surrounded by frost, these Martian dunes in Mars’ northern hemisphere were captured from above by NASA’s Mars Reconnaissance Orbiter using its HiRISE camera on Sept. 8, 2022. NASA/JPL-Caltech/University of Arizona Each northern spring is a little different, with variations leading to ice sublimating faster or slower, controlling the pace of all these phenomena on the surface. And these strange phenomena are just part of the seasonal changes on Mars: the southern hemisphere has its own unique activity.
More About MRO
The University of Arizona, in Tucson, operates HiRISE, which was built by Ball Aerospace & Technologies Corp., in Boulder, Colorado. NASA’s Jet Propulsion Laboratory, a division of Caltech in Pasadena, California, manages the Mars Reconnaissance Orbiter Project for NASA’s Science Mission Directorate, Washington.
For more information, visit:
https://science.nasa.gov/mission/mars-reconnaissance-orbiter
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Andrew Good
Jet Propulsion Laboratory, Pasadena, Calif.
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Last Updated Dec 20, 2024 Related Terms
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By NASA
3 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
The SpaceX Dragon Freedom spacecraft carrying NASA astronaut Nick Hague and Roscosmos cosmonaut Aleksandr Gorbunov approaches the International Space Station as it orbited 261 miles above Ontario, Canada, near James Bay. NASA published a new report Thursday highlighting 17 agency mechanisms that have directly and indirectly supported the development and growth of the U.S. commercial space sector for the benefit of humanity.
The report, titled Enabling America on the Space Frontier: The Evolution of NASA’s Commercial Space Development Toolkit, is available on the agency’s website.
“This is the most extensive and comprehensive historical analysis produced by NASA on how it has contributed to commercial space development over the decades,” said Alex MacDonald, NASA chief economist. “These efforts have given NASA regular access to space with companies, such as SpaceX and Rocket Lab, modernizing our communications infrastructure, and even led to the first private lunar lander thanks to Intuitive Machines. With commercial space growth accelerating, this report can help agency leaders and stakeholders assess the numerous mechanisms that the agency uses to support this growth, both now and in the future.”
Throughout its history, NASA has supported the development of the commercial space sector, not only leading the way in areas such as satellite communications, launch, and remote sensing, but also developing new contract and operational models to encourage commercial participation and growth. In the last three decades, NASA has seen the results of these efforts with commercial partners able to contribute more to missions across NASA domains, and increasingly innovative agency-led efforts to engage, nurture, and integrate these capabilities. These capabilities support the agency’s mission needs, and have seen a dramatic rise in importance, according to the report.
NASA has nurtured technology, companies, people, and ideas in the commercial space sector, contributing to the U.S. and global economies, across four distinct periods in the agency’s history:
1915–1960: NASA’s predecessor, the National Advisory Committee on Aeronautics (NACA), and NASA’s pre-Apollo years. 1961–1980: Apollo era. 1981–2010: Space shuttle era. 2011–present: Post-shuttle commercial era. Each of these time periods are defined by dominant technologies, programs, or economic trends further detailed in the report.
Though some of these mechanisms are relatively recent, others have been used throughout the history of NASA and NACA, leading to some overlap. The 17 mechanisms are as follows:
Contracts and Partnership Agreements Research and Technology Development (R&TD) Dissemination of Research and Scientific Data Education and Workforce Development Workforce External Engagement and Mobility Technology Transfer Technical Support Enabling Infrastructure Launch Direct In-Space Support Standards and Regulatory Framework Support Public Engagement Industry Engagement Venture Capital Engagement Market Stimulation Funding Economic Analysis and Due Diligence Capabilities Narrative Encouragement NASA supports commercial space development in everything from spaceflight to supply chains. Small satellite capabilities have inspired a new generation of space start-ups, while new, smaller rockets, as well as new programs are just starting. Examples include CLPS (Commercial Lunar Payload Services), commercial low Earth orbit destinations, human landing systems, commercial development of NASA spacesuits, and lunar terrain vehicles. The report also details many indirect ways the agency has contributed to the vibrance of commercial space, from economic analyses to student engagement.
The agency’s use of commercial capabilities has progressed from being the exception to the default method for many of its missions. The current post-shuttle era of NASA-supported commercial space development has seen a level of technical development comparable to the Apollo era’s Space Race. Deploying the 17 commercial space development mechanisms in the future are part of NASA’s mission to continue encouraging commercial space activities.
To learn more about NASA’s missions, please visit:
https//:www.nasa.gov
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Last Updated Dec 19, 2024 EditorBill Keeter Related Terms
Office of Technology, Policy and Strategy (OTPS) View the full article
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By NASA
Download PDF: Statistical Analysis Using Random Forest Algorithm Provides Key Insights into Parachute Energy Modulator System
Energy modulators (EM), also known as energy absorbers, are safety-critical components that are used to control shocks and impulses in a load path. EMs are textile devices typically manufactured out of nylon, Kevlar® and other materials, and control loads by breaking rows of stitches that bind a strong base webbing together as shown in Figure 1. A familiar EM application is a fall-protection harness used by workers to prevent injury from shock loads when the harness arrests a fall. EMs are also widely used in parachute systems to control shock loads experienced during the various stages of parachute system deployment.
Random forest is an innovative algorithm for data classification used in statistics and machine learning. It is an easy to use and highly flexible ensemble learning method. The random forest algorithm is capable of modeling both categorical and continuous data and can handle large datasets, making it applicable in many situations. It also makes it easy to evaluate the relative importance of variables and maintains accuracy even when a dataset has missing values.
Random forests model the relationship between a response variable and a set of predictor or independent variables by creating a collection of decision trees. Each decision tree is built from a random sample of the data. The individual trees are then combined through methods such as averaging or voting to determine the final prediction (Figure 2). A decision tree is a non-parametric supervised learning algorithm that partitions the data using a series of branching binary decisions. Decision trees inherently identify key features of the data and provide a ranking of the contribution of each feature based on when it becomes relevant. This capability can be used to determine the relative importance of the input variables (Figure 3). Decision trees are useful for exploring relationships but can have poor accuracy unless they are combined into random forests or other tree-based models.
The performance of a random forest can be evaluated using out-of-bag error and cross-validation techniques. Random forests often use random sampling with replacement from the original dataset to create each decision tree. This is also known as bootstrap sampling and forms a bootstrap forest. The data included in the bootstrap sample are referred to as in-the-bag, while the data not selected are out-of-bag. Since the out-of-bag data were not used to generate the decision tree, they can be used as an internal measure of the accuracy of the model. Cross-validation can be used to assess how well the results of a random forest model will generalize to an independent dataset. In this approach, the data are split into a training dataset used to generate the decision trees and build the model and a validation dataset used to evaluate the model’s performance. Evaluating the model on the independent validation dataset provides an estimate of how accurately the model will perform in practice and helps avoid problems such as overfitting or sampling bias. A good model performs well on
both the training data and the validation data.
The complex nature of the EM system made it difficult for the team to identify how various parameters influenced EM behavior. A bootstrap forest analysis was applied to the test dataset and was able to identify five key variables associated with higher probability of damage and/or anomalous behavior. The identified key variables provided a basis for further testing and redesign of the EM system. These results also provided essential insight to the investigation and aided in development of flight rationale for future use cases.
For information, contact Dr. Sara R. Wilson. sara.r.wilson@nasa.gov
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