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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
4 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
From left to right: Astrolab’s FLEX, Intuitive Machines’ Moon RACER, and Lunar Outpost’s Eagle lunar terrain vehicle at NASA’s Johnson Space Center. NASA/Bill Stafford Through NASA’s Artemis campaign, astronauts will land on the lunar surface and use a new generation of spacesuits and rovers as they live, work, and conduct science in the Moon’s South Pole region, exploring more of the lunar surface than ever before. Recently, the agency completed the first round of testing on three commercially owned and developed LTVs (Lunar Terrain Vehicle) from Intuitive Machines, Lunar Outpost, and Venturi Astrolab at NASA’s Johnson Space Center in Houston.
As part of an ongoing year-long feasibility study, each company delivered a static mockup of their vehicle to Johnson at the end of September, initiated rover testing in October and completed the first round of testing in December inside the Active Response Gravity Offload System (ARGOS) test facility. Lunar surface gravity is one-sixth of what we experience here on Earth, so to mimic this, ARGOS offers an analog environment that can offload pressurized suited subjects for various reduced gravity simulations.
NASA astronauts Raja Chari (left) and Randy Bresnik (right) sit inside Lunar Outpost’s Eagle lunar terrain vehicle evaluating the seat configuration during testing at NASA’s Johnson Space Center. NASA/David DeHoyos NASA astronaut Jessica Meir grabs a lunar geology tool from a tool rack on Lunar Outpost’s Eagle lunar terrain vehicle during testing at NASA’s Johnson Space Center.NASA/James Blair NASA astronaut Joe Acaba prepares to climb on top of Intuitive Machines’ Moon RACER lunar terrain vehicle to get to a science payload during testing at NASA’s Johnson Space Center.NASA/Josh Valcarcel NASA astronaut Jessica Meir puts a science sample inside of a storage box on Intuitive Machines’ Moon RACER lunar terrain vehicle during testing at NASA’s Johnson Space Center.NASA/James Blair NASA astronaut Frank Rubio (left) and NASA spacesuit engineer Zach Tejral (right) sit inside Astrolab’s FLEX lunar terrain vehicle evaluating the display interfaces during testing at NASA’s Johnson Space Center.NASA/James Blair NASA astronaut Jessica Watkins stores science payloads on Astrolab’s FLEX lunar terrain vehicle during testing at NASA’s Johnson Space Center.NASA/Robert Markowitz This is the first major test milestone within the Lunar Terrain Vehicle Services contract and to have actual rovers delivered only four months after these companies were awarded is remarkable.
steve munday
NASA's Lunar Terrain Vehicle Project Manager
NASA’s engineering teams conducted tests where suited NASA astronauts and engineers performed tasks, maneuvers, and emergency drills on each rover. With astronauts acting as the test subjects, these human-in-the-loop tests are invaluable as crewmembers provide critical feedback on each rover’s design functionality, evaluate display interfaces and controls, and help identify potential safety concerns or design issues. This feedback is shared directly with each commercial provider, to incorporate changes based on lessons learned as they evolve their rover design.
“We are excited to have mockups from all three LTV commercial providers here at Johnson Space Center,” said Steve Munday, LTV project manager. “This is the first major test milestone within the Lunar Terrain Vehicle Services contract and to have actual rovers delivered only four months after these companies were awarded is remarkable.”
NASA engineer Dave Coan (left) and NASA astronaut Jessica Watkins (right) sit inside from Intuitive Machines’ Moon RACER lunar terrain vehicle evaluating the crew compartment during testing at NASA’s Johnson Space Center.NASA/James Blair Testing consisted of NASA astronauts and engineers taking turns wearing both NASA’s Exploration Extravehicular Mobility Unit planetary prototype spacesuit as well as Axiom Space’s Axiom Extravehicular Mobility Unit lunar spacesuit. The test teams performed evaluations to understand the interactions between the crew, the spacesuits, and the LTV mockups.
While wearing NASA’s prototype spacesuit, crew members were suspended from ARGOS allowing teams to mimic theone-sixth gravitational field of the lunar surface. This allowed the crew members to conduct tasks on the outside of each rover, such as gathering or storing lunar geology tools, deploying science payloads, and handling cargo equipment, as if they are walking on the Moon.
NASA astronaut Joe Acaba raises the solar array panel on Lunar Outpost’s Eagle lunar terrain vehicle during testing at NASA’s Johnson Space Center.NASA/Robert Markowitz While wearing Axiom Space’s pressurized spacesuit, teams evaluated the level of ease or difficulty in mobility crewmembers experienced when entering and exiting the rovers, the crew compartment and design, and the functionality of interacting with display interfaces and hand controls while wearing thick spacesuit gloves.
As part of testing, teams also conducted emergency drills, where engineers simulated rescuing an incapacitated crew member. As part of NASA’s requirements, each rover must have a design in place that enables an astronaut to single-handedly rescue their crewmates in the event of an emergency.
NASA astronaut Jessica Watkins picks up a lunar geology tool from a stowage drawer on Astrolab’s FLEX lunar terrain vehicle during testing at NASA’s Johnson Space Center.NASA/Robert Markowitz Since NASA selected the companies, Intuitive Machines, Lunar Outpost, and Venturi Astrolab have been working to meet NASA’s requirements through the preliminary design review. In 2025, the agency plans to issue a request for task order proposals to any eligible providers for a demonstration mission to continue developing the LTV, deliver it to the surface of the Moon, and validate its performance and safety ahead of Artemis V, when NASA intends to begin using the LTV for crewed operations.
Through Artemis, NASA will send astronauts – including the next Americans, and the first international partner astronaut – to explore the Moon for scientific discovery, technology evolution, economic benefits, and to build the foundation for future crewed missions to Mars.
Learn about the rovers, suits, and tools that will help Artemis astronauts to explore more of the Moon:
https://go.nasa.gov/3MnEfrB
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Last Updated Dec 17, 2024 Related Terms
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By NASA
5 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
NASA’s Stennis Space Center enjoyed an active 2024, marking several milestones and engaging in frontline activities in several key areas. A compilation video offers a look at 2024 highlights in such areas of work as propulsion testing, autonomous systems, range operations, community outreach, and STEM engagement. NASA’s Stennis Space Center near Bay St. Louis, Mississippi, celebrated propulsion testing and site operations milestones in 2024, all while inspiring the Artemis Generation and welcoming new leadership that will help NASA Stennis innovate and grow into the future.
Featured highlights show a year of progress and vision, as NASA Stennis accelerates the exploration and commercialization of space, innovates to benefit NASA and industry, and leverages assets to grow as an impactful aerospace and technology hub.
“These highlights are just a small snapshot of 2024 at NASA Stennis that show the future is bright,” Bailey said. “We have an incredibly talented and committed team of employees – and all of Mississippi can be proud of the work they do here at NASA Stennis. Together, with the Artemis Generation leading the way, we are returning to the Moon. Together, we are a part of something great.”
New Center Leadership
NASA Stennis Director John Bailey, right, and NASA Stennis Deputy Director Christine Powell stand near the United States Capitol during a visit to Washington, D.C. on Sept. 18. It marked the first visit to Capitol Hill for the center leaders since being named to their current roles. NASA/Stennis NASA Administrator Bill Nelson named John Bailey as director of NASA Stennis in April. Bailey had been serving as acting director since January 2024. “So much of NASA runs through Stennis,” said Nelson. “It is where we hone new and exciting capabilities in aerospace, technology, and deep space exploration. I am confident that John will lead the nation’s largest and premier propulsion test site to even greater success.”
Four months later in August, Bailey announced that longtime propulsion engineer/manager Christine Powell had been selected as deputy director of NASA Stennis.
Powell, the first woman selected as NASA Stennis deputy director, began her 33-year agency career as an intern at the center in 1991. She previously worked in multiple Engineering and Test Directorate roles, and most recently served as manager of the NASA Rocket Propulsion Test Program Office.
Propulsion Activity
NASA achieves a major milestone for future Artemis missions with successful completion of the second – and final – RS-25 engine certification test series April 3 on the Fred Haise Test Stand at NASA’s Stennis Space Center. NASA/Danny Nowlin NASA achieved major milestones for future Artemis missions at NASA Stennis in 2024. The NASA Stennis test team successfully completed a second – and final – RS-25 engine certification test series in April. The mission-critical series verified engine upgrades designed to enhance efficiency and reliability for future SLS (Space Launch System) missions.
NASA Stennis crews also completed a safe lift and installation of the interstage simulator component in October needed for future testing of NASA’s exploration upper stage in the B-2 position of the Thad Cochran Test Stand. The component will function during Green Run testing like the SLS interstage section that helps protect the upper stage during Artemis launches.
The test complex milestones support NASA’s goal of returning humans to the Moon and paving the way for future Mars exploration through Artemis missions.
Commercial Testing
NASA Stennis commercial tenant Rocket Lab completes a successful hot fire test of its Archimedes engine in its onsite test complex in the second half of 2024. Rocket Lab is one of numerous customers conducting test campaigns at NASA Stennis during the most recent year. Rocket Lab Already the nation’s largest multiuser propulsion test site, NASA Stennis aims to continue fueling growth of the commercial space market even further by working with aerospace companies to support a range of testing needs. In 2024, NASA Stennis supported work conducted by commercial companies such as Boeing, Blue Origin, Evolution Space, Launcher (a Vast company), Relativity Space, Rocket Lab, and Rolls-Royce.
Officials from NASA Stennis and Roll-Royce also broke ground in June for a test pad located in the NASA Stennis E Test Complex. Rolls-Royce will conduct hydrogen testing for the Pearl 15 engine, which helps power the Bombardier Global 5500 & 6500 aircraft.
ASTRA Mission Success
Members of the NASA Stennis Autonomous Systems Laboratory team monitor the center’s in-space satellite payload from the onsite ASTRA (Autonomous Satellite Technology for Resilient Applications) Payload Operation Command Center. The ASTRA payload launched aboard the Sidus Space LizzieSat-1 small satellite in March 2024, with the NASA Stennis team announcing in July that it had achieved primary mission objectives. In September, the team announced the ASTRA mission would continue during the satellite’s planned four-year mission.NASA/Danny Nowlin In July, NASA Stennis and commercial partner Sidus Space Inc. announced primary mission success for the center’s historic in-space mission – an autonomous systems payload aboard an orbiting satellite.
ASTRA (Autonomous Satellite Technology for Resilient Applications) is the on-orbit payload mission developed by NASA Stennis. The NASA Stennis ASTRA technology demonstrator is a payload rider aboard the Sidus Space premier satellite, LizzieSat-1 (LS-1) small satellite. Partner Sidus Space is responsible for all LS-1 mission operations, including launch and satellite activation, which allowed the NASA Stennis ASTRA team to complete its primary mission objectives.
NASA Stennis announced in September it will continue the center’s in-space autonomous systems payload mission through a follow-on agreement with Sidus Space Inc.
Range Operations
The Skydweller Aero solar-powered, autonomous aircraft flies above the Thad Cochran Test Stand (B-1/B-2) at NASA’s Stennis Space Center during a September 2024 test operation. Skydweller Aero has an ongoing airspace agreement with NASA Stennis to conduct test flights of its aircraft in the area. Skydweller Aero During 2024, NASA Stennis entered into an agreement with Skydweller Aero Inc. for the company to operate its solar-powered autonomous aircraft in the site’s restricted airspace, a step towards achieving a strategic center goal.
The agreement marked the first Reimbursable Space Act agreement between NASA Stennis and a commercial company to utilize the south Mississippi center’s unique capabilities to support testing and operation of uncrewed systems.
The company announced in October it had completed an initial test flight campaign of the aircraft, including two test excursions totaling 16 and 22.5 hours.
NASA Engagement
NASA Stennis representatives inspire the Artemis Generation at the NAS Pensacola Blue Angels Homecoming Air Show on Nov. 1-2. NASA’s exhibits at the air show honored 55th anniversary of the Apollo 11 lunar landing and showcased the agency’s mission to inspire the world through discovery. NASA/Stennis NASA representatives participated in a variety of outreach activities during the past year to create meaningful connections with the Artemis Generation.
The NASA ASTRO CAMP® Community Partners program, which originated at the south Mississippi NASA center, surpassed previous milestone marks in fiscal year 2024 by partnering with 373 community sites, including 50 outside the United States, to inspire youth, families, and educators.
NASA Stennis also supported STEM (science, technology, engineering, and mathematics) engagement during the year. It once again joined with NASA’s Robotics Alliance Project and co-sponsor Mississippi Power to support the second annual For the Inspiration and Recognition of Science and Technology (FIRST) Robotics Magnolia Regional Competition in Laurel, Mississippi. The event attracted 37 high school teams from eight states and one from Mexico.
The center also supported NASA activities during the 2024 total solar eclipse. In addition, it hosted informational efforts and exhibits at high-visibility events such as the 51st Annual Bayou Classic, and Essence Fest in New Orleans.
For information about NASA’s Stennis Space Center, visit:
Stennis Space Center – NASA
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Last Updated Dec 16, 2024 EditorNASA Stennis CommunicationsContactC. Lacy Thompsoncalvin.l.thompson@nasa.gov / (228) 688-3333LocationStennis Space Center Related Terms
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By European Space Agency
A multi-orbit constellation of about 300 satellites that will deliver resilient, secure and fast communications for EU governments, European companies and citizens will be put in orbit after two contracts were confirmed today in Brussels.
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By NASA
On Thursday, Dec. 5, 2024, a team returns the Artemis II Orion spacecraft to the Final Assembly and Test cell from a vacuum chamber inside the Neil A. Armstrong Operations and Checkout Building at NASA’s Kennedy Space Center in Florida where it underwent vacuum testing. NASA/Eric Hernandez NASA’s Orion spacecraft for the Artemis II test flight returned to the Final Assembly and System Testing (FAST) cell following completion of the second round of vacuum chamber testing on Dec. 5 inside the Neil A. Armstrong Operations and Checkout Building at NASA’s Kennedy Space Center in Florida.
After returning to the FAST cell, the four main batteries – which supply power to many Orion systems – were installed in the crew module. The batteries returned to NASA Kennedy from their supplier, EaglePicher Technologies, earlier this month. Solar array wings will also be installed onto the spacecraft by international partner ESA (European Space Agency) and its contractor Airbus in early 2025.
The Artemis II test flight will be NASA’s first mission with crew under the Artemis campaign, sending NASA astronauts Reid Wiseman, Victor Glover, and Christina Koch, as well as CSA (Canadian Space Agency) astronaut Jeremy Hansen, on a 10-day journey around the Moon and back.
Image credit: NASA/Eric Hernandez
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