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By NASA
NASA has a strong need for advanced materials and processes (M&P) across the realms of robotic- and crewed-spaceflight, as well as aeronautics, particularly when one acknowledges that all craft must be made of something. To meet that need, the materials discipline relies on collaboration—both between centers and across disciplines. Reaching the Agency’s Moon-to-Mars objectives will require leveraging each center’s specific M&P expertise, cross-training among the centers, and routinely interacting with the 20-plus Agency disciplines like structures, space environments, and loads and dynamics. When a discipline touches all classes of materials; all aspects of design, manufacturing, testing, and operations; and all phases of flight, collaboration is the only way to broaden and deepen its reach.
This year, the Materials TDT pulled in wide-ranging center and discipline support for the VIPER lunar rover, investigations of cracks in the ISS Russian PrK, the X-59 supersonic aircraft, and the SLS Program. It also leveraged its contamination control experience to aid the Commercial Crew and Orion Programs. Below are some additional highlights from the year.
Collaboration Among Disciplines
Ms. Alison Park, NASA Deputy Technical Fellow for Materials, led a multi-disciplinary NESC team to address JPL’s request for sup – port to investigate anomalous temperature readings during thermal vacuum testing of the NASA Indian Space Research Organization (ISRO) Synthetic Aperture Rader (NISAR) reflect-array hardware, already integrated onto the spacecraft in India. The team provided detailed reviews of the thermal models and supported materials testing and characterization of the reflect-array construction record. The team’s work identified operability concerns from higher than expected temperatures that would be seen during the multi-day deployment process. The hardware was demated from the space – craft and returned to the United States for design upgrades and modifications to address the new concerns. The hardware is now set to return to India for reintegration and final launch preparations.
Fostering Intercenter Cooperation
Mr. Robert Carter, NASA Deputy Technical Fellow for Materials and GRC Deputy Division Chief, attended a technical exchange between GRC and MSFC. The exchange uncovered the need for an Agency-wide, materials-driven alloy development plan to identify key needs that would benefit spaceflight and aeronautics. From there, materials representatives from 7 of the 10 centers met in-person to develop a roadmap and a plan to be released in FY25. The Materials TDT also stood up an Alloy Development Community of Practice to provide a grassroots mechanism to identify cross-Agency needs, technical challenges, and benefits that aren’t identified programmatically or within mission directorates.
Illustration depicting the NISAR satellite in orbit over central and Northern California. The satellite features an advanced radar system to globally monitor changes to Earth’s land and ice surfaces to deepen scientists’ understanding of natural hazards, land use, climate change, and other global processes. In June 2023, NISAR’s radar instrument payload and spacecraft bus were combined in an ISRO clean room facility in Bengaluru, India. Image credit: VDOS-URSC Leveraging NASA Partnerships
The NASA Technical Fellow for Materials, Dr. Bryan W. McEnerney, hosted visitors from the European Space Agency (ESA) for a combined trip to JPL, GRC, and KSC, as well as the jointly organized Worldwide Advanced Manufacturing Symposium (WAMS) in Orlando, FL. In-depth technical interchanges between NASA and ESA emphasized advanced manufacturing with a focus on spaceflight needs. The event increased technical collaboration be – tween the two organizations, leading to ESA’s request to NASA for a formal review of ESA’s stress corrosion standard. Work was also initiated on a joint NASA/ESA intern program. Next year brings a number of new and exciting challenges, including an elevated temperature testing program focused on HallPetch effects in C-103 (niobium alloy), the domestic North American WAMS symposium in Knoxville, TN, and a continued focus on intercenter technical support. And, always a key objective, the discipline will actively engage early-career personnel on NESC assessments to learn from our veteran materials experts and to pass on the knowledge so unique to the space industry.
Alloy Development community of practice participants. Robert Carter is at center.View the full article
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By NASA
3 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
NASA’s Stennis Space Center near Bay St. Louis, Mississippi, is helping the Artemis Generation learn how to power space dreams with an interactive exhibit at INFINITY Science Center.
The engine test simulator exhibit at the official visitor center of NASA Stennis provides the chance to experience the thrill of being a NASA test engineer by guiding an RS-25 engine through a simulated hot fire test.
“It is an exhilarating opportunity to feel what it is like to be a NASA engineer, responsible for making sure the engine is safely tested for launch,” said Chris Barnett-Woods, a NASA engineer that helped develop the software for the exhibit.
Sitting at a console mirroring the actual NASA Stennis Test Control Center, users are immersed in the complex process of engine testing. The exhibit uses cutting-edge software and visual displays to teach participants how to manage liquid oxygen and liquid hydrogen propellants, and other essential elements during a hot fire.
A pair of young visitors to INFINITY Science Center carry out the steps of a simulated RS-25 engine hot fire on Dec. 19. The updated engine test simulator exhibit provided by NASA’s Stennis Space Center takes users through the hot fire process just as real engineers do at NASA Stennis.NASA/Danny Nowlin INFINITY Science Center, the official visitor center for NASA’s Stennis Space Center, has unveiled a new interactive simulator exhibit that allows visitors to become the test conductor for an RS-25 engine hot fire. NASA/Danny Nowlin Users follow step-by-step instructions that include pressing buttons, managing propellant tanks, and even closing the flare stack, just as real engineers do at NASA Stennis. Once the test is complete, they are congratulated for successfully conducting their own rocket engine hot fire.
The interactive exhibit is not just about pushing buttons. It is packed with interesting facts about the RS-25 engine, which helps power NASA’s Artemis missions as the agency explores secrets of the universe for the benefit of all. Visitors also can view real hot fires conducted at NASA Stennis from multiple angles, deepening their understanding of rocket propulsion testing and NASA’s journey back to the Moon and beyond.
NASA is currently preparing for the Artemis II mission, the first crewed flight test of the agency’s powerful SLS (Space Launch System) rocket and the Orion spacecraft around the Moon.
The first four Artemis missions are using modified space shuttle main engines tested at NASA Stennis. The center also achieved a testing milestone last April for engines to power future Artemis missions. For each Artemis mission, four RS-25 engines, along with a pair of solid rocket boosters, power NASA’s SLS rocket, producing more than 8.8 million pounds of total combined thrust at liftoff.
The revitalized exhibit, previously used when the visitor center was located onsite, represents a collaborative effort. It started as an intern project in the summer of 2023 before evolving into a full-scale experience. Engineers built on the initial concept, integrating carpentry, audio, and video to create the seamless experience to educate and inspire.
The best part might be that visitors to INFINITY Science Center can repeat the simulation as many times as they like, gaining confidence and learning more with each attempt.
“This exhibit was a favorite in the past, and with its new upgrades, the engine test simulator is poised to capture the imaginations of the Artemis Generation at INFINITY Science Center,” said NASA Public Affairs Specialist Samone Wilson. “This is one exhibit you will not want to miss.” INFINITY Science Center is located at 1 Discovery Circle, Pearlington, Mississippi. For hours of operation and admission information, please visit www.visitinfinity.com.
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Last Updated Dec 20, 2024 EditorNASA Stennis CommunicationsContactC. Lacy Thompsoncalvin.l.thompson@nasa.gov / (228) 688-3333LocationStennis Space Center Related Terms
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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 NASA
5 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
Data from the SWOT satellite was used to calculate average water levels for lakes and reservoirs in the Ohio River Basin from July 2023 to November 2024. Yellow indicates values greater than 1,600 feet (500 meters) above sea level; dark purple represents water levels less than 330 feet (100 meters). Data from the U.S.-European Surface Water and Ocean Topography mission gives researchers a detailed look at lakes and reservoirs in a U.S. watershed.
The Ohio River Basin stretches from Pennsylvania to Illinois and contains a system of reservoirs, lakes, and rivers that drains an area almost as large as France. Researchers with the SWOT (Surface Water and Ocean Topography) mission, a collaboration between NASA and the French space agency CNES (Centre National d’Études Spatiales), now have a new tool for measuring water levels not only in this area, which is home to more than 25 million people, but in other watersheds around the world as well.
Since early 2023, SWOT has been measuring the height of nearly all water on Earth’s surface — including oceans, lakes, reservoirs, and rivers — covering nearly the entire globe at least once every 21 days. The SWOT satellite also measures the horizontal extent of water in freshwater bodies. Earlier this year, the mission started making validated data publicly available.
“Having these two perspectives — water extent and levels — at the same time, along with detailed, frequent coverage over large areas, is unprecedented,” said Jida Wang, a hydrologist at the University of Illinois Urbana-Champaign and a member of the SWOT science team. “This is a groundbreaking, exciting aspect of SWOT.”
Researchers can use the mission’s data on water level and extent to calculate how the amount of water stored in a lake or reservoir changes over time. This, in turn, can give hydrologists a more precise picture of river discharge — how much water moves through a particular stretch of river.
The visualization above uses SWOT data from July 2023 to November 2024 to show the average water level above sea level in lakes and reservoirs in the Ohio River Basin, which drains into the Mississippi River. Yellow indicates values greater than 1,600 feet (500 meters), and dark purple represents water levels less than 330 feet (100 meters). Comparing how such levels change can help hydrologists measure water availability over time in a local area or across a watershed.
Complementing a Patchwork of Data
Historically, estimating freshwater availability for communities within a river basin has been challenging. Researchers gather information from gauges installed at certain lakes and reservoirs, from airborne surveys, and from other satellites that look at either water level or extent. But for ground-based and airborne instruments, the coverage can be limited in space and time. Hydrologists can piece together some of what they need from different satellites, but the data may or may not have been taken at the same time, or the researchers might still need to augment the information with measurements from ground-based sensors.
Even then, calculating freshwater availability can be complicated. Much of the work relies on computer models. “Traditional water models often don’t work very well in highly regulated basins like the Ohio because they have trouble representing the unpredictable behavior of dam operations,” said George Allen, a freshwater researcher at Virginia Tech in Blacksburg and a member of the SWOT science team.
Many river basins in the United States include dams and reservoirs managed by a patchwork of entities. While the people who manage a reservoir may know how their section of water behaves, planning for water availability down the entire length of a river can be a challenge. Since SWOT looks at both rivers and lakes, its data can help provide a more unified view.
“The data lets water managers really know what other people in these freshwater systems are doing,” said SWOT science team member Colin Gleason, a hydrologist at the University of Massachusetts Amherst.
While SWOT researchers are excited about the possibilities that the data is opening up, there is still much to be done. The satellite’s high-resolution view of water levels and extent means there is a vast ocean of data that researchers must wade through, and it will take some time to process and analyze the measurements.
More About SWOT
The SWOT satellite was jointly developed by NASA and CNES, with contributions from the Canadian Space Agency (CSA) and the UK Space Agency. NASA’s Jet Propulsion Laboratory, managed for the agency by Caltech in Pasadena, California, leads the U.S. component of the project. For the flight system payload, NASA provided the Ka-band radar interferometer (KaRIn) instrument, a GPS science receiver, a laser retroreflector, a two-beam microwave radiometer, and NASA instrument operations. The Doppler Orbitography and Radioposition Integrated by Satellite system, the dual frequency Poseidon altimeter (developed by Thales Alenia Space), the KaRIn radio-frequency subsystem (together with Thales Alenia Space and with support from the UK Space Agency), the satellite platform, and ground operations were provided by CNES. The KaRIn high-power transmitter assembly was provided by CSA.
To learn more about SWOT, visit:
https://swot.jpl.nasa.gov
News Media Contacts
Jane J. Lee / Andrew Wang
Jet Propulsion Laboratory, Pasadena, Calif.
818-354-0307 / 626-379-6874
jane.j.lee@jpl.nasa.gov / andrew.wang@jpl.nasa.gov
2024-176
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Last Updated Dec 17, 2024 Related Terms
SWOT (Surface Water and Ocean Topography) Jet Propulsion Laboratory Water on Earth Explore More
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