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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
Dawn Asteroids Ceres Jet Propulsion Laboratory Vesta Explore More
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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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By European Space Agency
Relive Europe’s greatest space achievements of the year
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By NASA
9 Min Read Artemis in Motion Listening Sessions
The Earth and Moon appear side by side off in the distance while the Orion crew module is in the foreground. Credits: NASA Through Artemis in Motion Sessions, NASA Seeks Moon Storytelling Ideas
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As NASA pioneers new technologies and methods for storytelling in space for the benefit of humanity, the agency is hosting Artemis in Motion listening sessions with industry on Thursday, Jan. 23, and Friday, Jan. 24, in Los Angeles.
From the live TV images of humanity’s first steps on the Moon in July of 1969 to the July 2024 two-way 4k transmissions between the International Space Station and an airborne platform, NASA and its partners work on the frontiers of the media landscape to share historic achievements in space exploration.
As part of its Artemis campaign, NASA will land the next American astronauts and first international astronaut on the Moon, explore more of the Moon than ever before, and more.
Through NASA’s listening sessions, invited participants will learn about the agency’s work to tell the Artemis Generation’s lunar exploration story, and discuss new opportunities to highlight the agency’s work.
Today’s advances in technology, storytelling, and production make it possible to share the experience of landing, living, and working on the Moon in ways never before possible. NASA wants to hear how participants would share the extraordinary story of sustained human presence and exploration throughout the solar system, which is rooted across three balanced pillars of science, inspiration, and national posture.
NASA’s OTPS (Office of Technology, Policy, and Strategy), Office of Communications, and the Exploration System Mission Directorate are organizing the sessions in coordination with Science Mission Directorate, and the Space Operations Mission Directorate.
Overview
With the Artemis campaign, NASA is returning to the Moon to discover the unknown, advance technology, and to learn how to live and work on another world as we prepare for human missions to Mars.
Artemis I successfully completed an uncrewed mission in 2022, and in 2026 Artemis II will next send four crew members to fly around the Moon. As early as mid-2027, Artemis III and subsequent missions will once again bring humans back to the surface of the Moon, landing for the first time where no people have been before: the lunar South Pole region. Like the historic Apollo landings 50 years ago, these missions to the surface of the Moon will provide unparalleled opportunities for motion imagery to inspire and ignite the imagination of people around the world.
NASA and its commercial partners will have integrated cameras on human landing systems and spacesuits, as well as each astronaut carrying their own handheld camera. But we know the modern age offers many creative ways to share these moments, ways to let each of us “ride along” with the crew. NASA is calling on media producers and distributors, studios, imagery companies, space companies, academia, and other interested parties to share their ideas directly with NASA leadership.
Each participant will be asked to make a 30-minute presentation to be delivered in a one-on-one session to the NASA team. Concepts should focus on the Artemis III-V missions (for more on each Artemis missions see NASA’s Moon to Mars Architecture), particularly the time they will spend on the lunar surface. NASA has particular interest in information that informs three key questions:
What could supplement NASA’s planned acquisition, communication, distribution, etc. of lunar imagery? (See the FAQ section for an overview of our current plans.) What could be done with the video, photography, and telemetry from the mission(s) to creatively share the return of humans to the Moon in unique and compelling ways? How could NASA collaborate with your organization to help NASA tell the story of Artemis in a unique way? There are no associated activities (e.g., procurement, cooperative agreement, Space Act agreement, etc.) planned at this time.
Session Details
Beyond the in-person events already planned and depending on demand, NASA may offer additional virtual sessions the week of February 3rd. The agency also is engaging the entertainment community through a private panel presentation at the Motion Picture Academy.
If space allows, participants will be invited to attend an information session on the Artemis campaign and its motion imagery opportunities the morning of Jan. 23. We will provide more information on the optional briefing upon RSVP.
Organizations interested in booking a listening session should email their request to: hq-dl-artemis-in-motion@mail.nasa.gov with the following information by Monday, Jan. 13:
Organization name Participant name(s) – limit to three Point of contact email and phone number Request for in-person or virtual session NASA will set the session schedule and contact organizations directly to confirm all details. No slide decks or digital presentations are permitted during the sessions, although you may bring printed materials.
Please do not share confidential or proprietary information during the sessions. We will not record the sessions, however, NASA staff may take notes.
For more information on the Artemis in Motion listening sessions, please read our FAQ section below. You may send additional questions or requests for guidance on your presentation to hq-dl-artemis-in-motion@mail.nasa.gov. Please note we may add your questions to the FAQ below if deemed helpful to other participants.
Artemis in Motion Listening Sessions FAQ
Q: Does NASA have any specific opportunities it is seeking ideas for?
A: NASA is looking to explore the art of the possible in ideas that supplement, improve, or expand the use of imagery from the lunar surface, and will accept any information on ideas that forward the story of Artemis and that adheres with NASA’s principles. The following list of potential opportunities are examples of what may interest the listening team. These are examples only and not meant to restrict the scope of presentations.
A deployable or separately landed camera system for third-person point-of-view imagery from the lunar surface.
A deployable or separately landed camera system for third-person point-of-view imagery from the lunar surface. Non-traditional imagery options including virtual reality, augmented reality, and similar immersive technologies. Collaboration with the NASA+ team to stream a live event to a very large audience. A TV series or production leading up to and around the Artemis missions. An efficient, space-rated encoder to transmit live, high-quality video from the HULC (Handheld Universal Lunar Camera), a ruggedized version of the Nikon Z9. Processing techniques to increase data throughput or recall for ground operations. An approach to increasing the bandwidth available to downlink more or higher quality videos. Q: What sources of imagery does NASA already plan to have on the lunar surface?
A: NASA expects to have access to at least three sources of imagery on the lunar surface:
External and internal video cameras mounted on the Human Landing System. A video camera mounted on each astronaut suit, providing the perspective of the crew members during EVA. The HULC (a modified Nikon Z 9) that will be carried by each crew member to provide real-time photography. These sources will offer a variety of perspectives, including live video up to UHD resolution. Video will be standard 16:9 format; there are no current plans for stereoscopic video, 360-degree cameras, or spatial video/audio.
NASA currently plans to stream live content via its NASA+ platform as an over-the-top service, as well as provide a backhaul feed to the media. It will also archive and release the photography and video, including any imagery returned from the Moon later with the crew.
Q: How would additional imagery be routed on the Moon and back to Earth?
A: NASA imagery will be routed through the Human Landing System and then downlinked to Earth via the Deep Space Network (DSN). Equipment on the surface of the Moon will transmit imagery to the Human Landing System via Wi-Fi; Artemis III may also include a development test objective for a 4G/LTE connection. We expect limited data bandwidth for any non-critical video links, ranging from single-digit to low double-digit megabits per second. It could be possible for solutions to support increased bandwidth by supporting downlink direct to Earth or through a lunar relay system.
Q: What is the weight limit for new systems brought to the Moon?
A: While there isn’t a specific weight limit, additional imagery systems ideally are low in mass, size, weight, power, and bandwidth due to the limited capacity for the early Artemis missions.
Q: Can an organization propose a production or solution for which they would have exclusive rights?
A: NASA has previously entered into content agreements with organizations that involve some level of exclusivity. However, NASA seeks to benefit all humanity and especially desires solutions that can be shared with the widest possible audience.
Q: Can an organization propose a production that involves content before and after the mission such as content with crew members?
A: Yes. NASA expects the story of a mission to not just include the time on the Moon, but the launch and splashdown; the story of the Artemis campaign to not just include the mission itself but the engineering, the training, the uncrewed test flights, and their impact.
Q: Are listening sessions open to organizations outside the United States?
A: Yes, participation by international entities is encouraged. International space agencies interested in discussing opportunities are encouraged to reach out directly to hq-dl-artemis-in-motion@mail.nasa.gov.
Q: Can NASA help certify or design the hardware for use on the Lunar Surface?
A: Any hardware would need to meet the NASA interface and safety requirements to fly. The specifics of those interfaces, as well as the possibility of NASA support in meeting them, would be discussed in any follow-on discussions or solicitations. (As a reminder, NASA is also interested in concepts that do not require providing and flying new hardware.)
Q: Must any solution be completely autonomously operated or could it link to a suit or the Human Landing System for data and power and/or be operated by a crew member?
A: A solution could provide its own communication system or it could route data transmission to and through the Human Landing System, which could be done via Wi-Fi (Artemis III may also include a development test objective for a 4G/LTE connection). Routing data through or getting power from the suit is likely to not be a feasible option. Crew may be able to set up a camera on the lunar surface, but crew time is too constrained to expect the crew to continue to operate the camera. Human Landing System support for providing power for or exchanging commands with a payload would need to be evaluated on a case-by-case basis.
Q: Will information from the presentations be shared?
A: NASA does not intend to share information from the individual sessions outside of the agency.
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Last Updated Dec 11, 2024 EditorBill Keeter Related Terms
Office of Technology, Policy and Strategy (OTPS) View the full article
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