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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
News Media Contact
Ian J. O’Neill
Jet Propulsion Laboratory, Pasadena, Calif.
818-354-2649
ian.j.oneill@jpl.nasa.gov
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Last Updated Dec 20, 2024 Related Terms
Deep Space Network Jet Propulsion Laboratory Space Communications & Navigation Program Space Operations Mission Directorate Explore More
4 min read Lab Work Digs Into Gullies Seen on Giant Asteroid Vesta by NASA’s Dawn
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By NASA
Illustration of the main asteroid belt, orbiting the Sun between Mars and JupiterNASA NASA’s powerful James Webb Space Telescope includes asteroids on its list of objects studied and secrets revealed.
A team led by researchers at the Massachusetts Institute of Technology (MIT) in Cambridge repurposed Webb’s observations of a distant star to reveal a population of small asteroids — smaller than astronomers had ever detected orbiting the Sun in the main asteroid belt between Mars and Jupiter.
The 138 new asteroids range from the size of a bus to the size of a stadium — a size range in the main belt that has not been observable with ground-based telescopes. Knowing how many main belt asteroids are in different size ranges can tell us something about how asteroids have been changed over time by collisions. That process is related to how some of them have escaped the main belt over the solar system’s history, and even how meteorites end up on Earth.
“We now understand more about how small objects in the asteroid belt are formed and how many there could be,” said Tom Greene, an astrophysicist at NASA’s Ames Research Center in California’s Silicon Valley and co-author on the paper presenting the results. “Asteroids this size likely formed from collisions between larger ones in the main belt and are likely to drift towards the vicinity of Earth and the Sun.”
Insights from this research could inform the work of the Asteroid Threat Assessment Project at Ames. ATAP works across disciplines to support NASA’s Planetary Defense Coordination Office by studying what would happen in the case of an Earth impact and modeling the associated risks.
“It’s exciting that Webb’s capabilities can be used to glean insights into asteroids,” said Jessie Dotson, an astrophysicist at Ames and member of ATAP. “Understanding the sizes, numbers, and evolutionary history of smaller main belt asteroids provides important background about the near-Earth asteroids we study for planetary defense.”
Illustration of the James Webb Space TelescopeNASA The team that made the asteroid detections, led by research scientist Artem Burdanov and professor of planetary science Julien de Wit, both of MIT, developed a method to analyze existing Webb images for the presence of asteroids that may have been inadvertently “caught on film” as they passed in front of the telescope. Using the new image processing technique, they studied more than 10,000 images of the star TRAPPIST-1, originally taken to search for atmospheres around planets orbiting the star, in the search for life beyond Earth.
Asteroids shine more brightly in infrared light, the wavelength Webb is tuned to detect, than in visible light, helping reveal the population of main belt asteroids that had gone unnoticed until now. NASA will also take advantage of that infrared glow with an upcoming mission, the Near-Earth Object (NEO) Surveyor. NEO Surveyor is the first space telescope specifically designed to hunt for near-Earth asteroids and comets that may be potential hazards to Earth.
The paper presenting this research, “Detections of decameter main-belt asteroids with JWST,” was published Dec. 9 in Nature.
The James Webb Space Telescope is the world’s premier space science observatory. Webb is solving mysteries in our solar system, looking beyond to distant worlds around other stars, and probing the mysterious structures and origins of our universe and our place in it. Webb is an international program led by NASA with its partners, ESA (European Space Agency) and CSA (Canadian Space Agency).
For news media:
Members of the news media interested in covering this topic should reach out to the NASA Ames newsroom.
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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
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Last Updated Dec 20, 2024 Related Terms
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By NASA
Download PDF: Contact Dynamics Predictions Utilizing theNESC Parameterless Contact Model
Modeling the capture of the Mars Sample Return (MSR) Orbiting Sample (OS) involves understanding complex dynamic behavior, which includes the OS making contact against the interior of the capture enclosure. The MSR Program required numerical verification of the contact dynamics’ predictions produced using their commercial software tools. This commercial software used “free” parameters to set up the contact modeling. Free parameters (also known as free variables) are not based on contact physics. The commercial contact model used by MSR
required seven free parameters including a Hertzian contact stiffness, surface penetration, stiffening exponent, penetration velocity, contact damping, maximum penetration depth for the contact damping value, and a smoothing function. An example of a parameter that is not free is coefficient of friction, which is a physics-based parameter. Consider the free parameter, contact stiffness. Contact stiffness is already present in the finite element model’s (FEM) stiffness matrix where the bodies come into contact, and surface penetration is disallowed in a physically realizable contact model, as FEM meshes should not penetrate one another during contact (i.e., the zero-contact limit penetration constraint condition).
As such, with each set of selected free parameters generating a different contact force signature, additional numerical verification is required to guide setting these parameters. Contact modeling is nonlinear. This means that the stiffness matrices of contacting bodies are continuously updated as the bodies come into contact, potentially recontact (due to vibrations), and disengage. The modal properties of contacting bodies continuously change with state transitions (e.g., stick-to-slip). Some contact models have been proposed and incorporated in commercial finite element analysis solvers, and most involve static loading. A relatively smaller number involve dynamics, which has historically proven challenging.
In 2005, NASA conducted a study testing several commercial contact solvers in predicting contact forces in transient dynamic environments. This was necessitated by the Space Shuttle Program (SSP)—after the February 2003 Columbia accident— deciding to include contact dynamics in the Space Shuttle transient coupled loads analysis (CLA) to capture the impact of contact nonlinearities. This rendered the entire CLA nonlinear. The study found major difficulties executing nonlinear CLAs in commercial software. A nonlinear solver developed by the NESC and Applied Structural Dynamics (ASD) that was able to produce physically realizable results was numerically verified by NASA and later experimentally validated as well. This nonlinear solver was subsequently utilized to execute all NASA SSP CLAs (i.e., crewed space flights) from 2005 to the final flight in 2011, as well as currently supporting the SLS Program.
The objective of the MSR contact verification work was to provide data that could be used by the MSR team to help define the free parameters listed above for the commercial tool contact model. The NESC/ASD solver was used to model contact between simple cantilever and free beams, deriving contact forces and relative displacements. These resulting data can be used to determine parameter values for more complex structures. Two of the modeled configurations, one for axial contact (Figure 1) and the other for stick/friction (Figure 2), and sample results from the NESC nonlinear dynamic analyses are presented in Figures 1 and 2.
For information, contact:
Dr. Dexter Johnson dexter.johnson@nasa.gov
Dr. Arya Majed arya.majed@nasa.gov
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By NASA
ESA/Webb, NASA & CSA, P. Zeidler This new image of star cluster NGC 602, released on Dec. 17, 2024, combines data from NASA’s Chandra X-ray Observatory with a previously released image from the agency’s James Webb Space Telescope. Webb data provide the ring-like outline of the “wreath,” while X-rays from Chandra (red) show young, massive stars that are illuminating the wreath, sending high-energy light into interstellar space.
NGC 602 lies on the outskirts of the Small Magellanic Cloud, which is one of the closest galaxies to the Milky Way, about 200,000 light-years from Earth.
See another new, festive image: the “Christmas tree cluster.”
Image credit: X-ray: NASA/CXC; Infrared: ESA/Webb, NASA & CSA, P. Zeilder, E.Sabbi, A. Nota, M. Zamani; Image Processing: NASA/CXC/SAO/L. Frattare and K. Arcand
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