Jump to content

Operational Modal Analysis of the Artemis I Dynamic Rollout Test


Recommended Posts

  • Publishers
Posted

Operational modal analysis (OMA) techniques have been used to identify the modal characteristics of the Artemis I launch vehicle during the Dynamic Rollout Test (DRT) and Wet Dress Rehearsal (WDR) configuration prior to launch. Forces induced during rollout and on the launch pad are not directly measurable, thus necessitating a unique approach.

NASA is developing the SLS to support lunar and deep space exploration. SLS is integrated inside the Vehicle Assembly Building (VAB) on the mobile launcher (ML), which supports the integrated SLS launch vehicle during transport to the pad through lift-off. The ML also provides the fuel, power, and data umbilicals running to the SLS and Orion Multi-Purpose Crew Vehicle (MPCV), as well as crew access to the MPCV crew module. The ML weighs ~10.6 million pounds and is over 380 feet tall. In the spring of 2022, the SLS was transported on the ML from the VAB to Launch Pad 39B (Figure 1) using the NASA crawler transporter (CT) to make this 4.2 mile trek, which takes ~8 hours. The CT alone weighs ~6.3 million pounds.

techup2023-pg64-art1.png?w=634
Figure 1. Artemis I Rollout to Launch Pad 39B.

Although the rollout environment produces relatively small launch vehicle structural loads in comparison to launch and ascent loads for most structures, the induced loads are fully representative of all loading across the entire vehicle, which is not feasible to replicate using localized shakers as was done in the Integrated Modal Test. As mentioned, forces induced during rollout and on the launch pad are not directly measurable, and OMA techniques were used to identify the modal characteristics of Artemis I in the DRT and WDR configurations. WDR, which typically includes vehicle fueling and other operations to demonstrate launch readiness, included several days of on-pad operations. Data collected for the WDR configuration, with partially filled core fuel tanks and without the CT under the ML, provided engineers another model configuration to check (Figure 2).

techup2023-pg64-art2.png?w=2048
Figure 2. Artemis I at Launch Pad 39B.

Acquisition and processing the data from over 300 accelerometers located on Artemis I, ML, and CT was accomplished by a cross-program team of engineers and technicians from across the Agency, including from SLS, Exploration Ground Systems, and the NESC. Using analytical techniques developed from previous rollout tests combined with new data-processing methodologies, the team processed data from preselected CT speed increments during rollout and on-pad during WDR. By making the necessary modifications to the integrated models to match both the DRT and WDR configurations, the team was able to use those results to help make sense of what was being seen in the test data. This proved to be required for OMA testing on this structure, given the type of complex excitation that was being observed.

For information, contact Dexter Johnson dexter.johnson@nasa.gov and Teresa Kinney teresa.l.kinney@nasa.gov.

View the full article

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Similar Topics

    • By NASA
      Credit: NASA Following an international signing ceremony Thursday, NASA congratulated Norway on becoming the latest country to join the Artemis Accords, committing to the peaceful, transparent, and responsible exploration of space.
      “We’re grateful for the strong and meaningful collaboration we’ve already had with the Norwegian Space Agency,” said acting NASA Administrator Janet Petro. “Now, by signing the Artemis Accords, Norway is not only supporting the future of exploration, but also helping us define it with all our partners for the Moon, Mars, and beyond.”
      Norway’s Minster of Trade and Industry Cecilie Myrseth signed the Artemis Accords on behalf of the country during an event at the Norwegian Space Agency (NOSA) in Oslo. Christian Hauglie-Hanssen, director general of NOSA, and Robert Needham, U.S. Embassy Chargé d’Affaires for Norway, participated in the event. Petro contributed remarks in a pre-recorded video message.
      “We are pleased to be a part of the Artemis Accords,” said Myrseth. “This is an important step for enabling Norway to contribute to broader international cooperation to ensure the peaceful exploration and use of outer space.”
      In 2020, the United States, led by NASA and the U.S. Department of State, and seven other initial signatory nations established the Artemis Accords, the first set of practical guidelines for nations to increase safety of operations and reduce risk and uncertainty in their civil exploration activities.
      The Artemis Accords are grounded in the Outer Space Treaty and other agreements including the Registration Convention and the Rescue and Return Agreement, as well as best practices for responsible behavior that NASA and its partners have supported, including the public release of scientific data. 
      Learn more about the Artemis Accords at:
      https://www.nasa.gov/artemis-accords
      -end-
      Amber Jacobson / Elizabeth Shaw
      Headquarters, Washington
      202-358-1600
      amber.c.jacobson@nasa.gov / elizabeth.a.shaw@nasa.gov
      Share
      Details
      Last Updated May 15, 2025 EditorJessica TaveauLocationNASA Headquarters Related Terms
      Artemis Accords Office of International and Interagency Relations (OIIR) View the full article
    • By NASA
      Teams at NASA’s Michoud Assembly Facility in New Orleans move a liquid hydrogen tank for the agency’s SLS (Space Launch System) rocket into the factory’s final assembly area on April 22, 2025. The propellant tank is one of five major elements that make up the 212-foot-tall rocket stage. NASA/Steven Seipel NASA completed another step to ready its SLS (Space Launch System) rocket for the Artemis III mission as crews at the agency’s Michoud Assembly Facility in New Orleans recently applied a thermal protection system to the core stage’s liquid hydrogen tank.
      Building on the crewed Artemis II flight test, Artemis III will add new capabilities with the human landing system and advanced spacesuits to send the first astronauts to explore the lunar South Pole region and prepare humanity to go to Mars. Thermal protection systems are a cornerstone of successful spaceflight endeavors, safeguarding human life, and enabling the launch and controlled return of spacecraft.
      The tank is the largest piece of SLS flight hardware insulated at Michoud. The hardware requires thermal protection due to the extreme temperatures during launch and ascent to space – and to keep the liquid hydrogen at minus 423 degrees Fahrenheit on the pad prior to launch.
      “The thermal protection system protects the SLS rocket from the heat of launch while also keeping the thousands of gallons of liquid propellant within the core stage’s tanks cold enough. Without the protection, the propellant would boil off too rapidly to replenish before launch,” said Jay Bourgeois, thermal protection system, test, and integration lead at NASA Michoud. “Thermal protection systems are crucial in protecting all the structural components of SLS during launch and flight.”
      In February, Michoud crews with NASA and Boeing, the SLS core stage prime contractor, completed the thermal protection system on the external structure of the rocket’s liquid hydrogen propellant fuel tank, using a robotic tool in what is now the largest single application in spaceflight history. The robotically controlled operation coated the tank with spray-on foam insulation, distributing 107 feet of the foam to the tank in 102 minutes. When the foam is applied to the core stage, it gives the rocket a canary yellow color. The Sun’s ultraviolet rays naturally “tan” the thermal protection, giving the SLS core stage its signature orange color, like the space shuttle external tank.
      Having recently completed application of the thermal protection system, teams will now continue outfitting the 130-foot-tall liquid hydrogen tank with critical systems to ready it for its designated Artemis III mission. The core stage of SLS is the largest ever built by length and volume, and was manufactured at Michoud using state-of-the-art manufacturing equipment. (NASA/Steven Seipel) While it might sound like a task similar to applying paint to a house or spraying insulation in an attic, it is a much more complex process. The flexible polyurethane foam had to withstand harsh conditions for application and testing. Additionally, there was a new challenge: spraying the stage horizontally, something never done previously during large foam applications on space shuttle external tanks at Michoud. All large components of space shuttle tanks were in a vertical position when sprayed with automated processes.
      Overall, the rocket’s core stage is 212 feet with a diameter of 27.6 feet, the same diameter as the space shuttle’s external tank. The liquid hydrogen and liquid oxygen tanks feed four RS-25 engines for approximately 500 seconds before SLS reaches low Earth orbit and the core stage separates from the upper stage and NASA’s Orion spacecraft.
      “Even though it only takes 102 minutes to apply the spray, a lot of careful preparation and planning is put into this process before the actual application of the foam,” said Boeing’s Brian Jeansonne, the integrated product team senior leader for the thermal protection system at NASA Michoud. “There are better process controls in place than we’ve ever had before, and there are specialized production technicians who must have certifications to operate the system. It’s quite an accomplishment and a lot of pride in knowing that we’ve completed this step of the build process.”
      The core stage of SLS is the largest NASA has ever built by length and volume, and it was manufactured at Michoud using state-of-the-art manufacturing equipment. Michoud is a unique, advanced manufacturing facility where the agency has built spacecraft components for decades, including the space shuttle’s external tanks and Saturn V rockets for the Apollo program.
      Through Artemis, NASA will send astronauts to explore the Moon for scientific discovery, economic benefits, and build the foundation for the first crewed missions to Mars.
      For more information on the Artemis Campaign, visit:
      https://www.nasa.gov/feature/artemis/
      News Media Contact
      Jonathan Deal
      Marshall Space Flight Center, Huntsville, Ala. 
      256-544-0034 
      jonathan.e.deal@nasa.gov
      View the full article
    • By NASA
      Artemis II crew members, shown inside the Neil Armstrong Operations and Checkout Building at NASA’s Kennedy Space Center in Florida, stand in front of their Orion crew module on Aug. 8, 2023. Pictured from left are CSA (Canadian Space Agency) astronaut Jeremy Hansen, and NASA astronauts Victor Glover, Reid Wiseman, and Christina Koch.Credit: NASA/Kim Shiflett NASA will host a live Twitch event to highlight the ongoing Moon Mascot Challenge, which invites the public to design a zero gravity indicator for the agency’s Artemis II crewed test flight around the Moon. Viewers will have the opportunity to provide real-time input to an artist who will create an example of a zero gravity indicator during the livestream. 
      Zero gravity indicators are small, plush items carried aboard spacecraft to provide a visual indication of when the crew reaches space.
      The event will begin at 3 p.m. EDT on Tuesday, May 13, on the agency’s official Twitch channel:
      https://www.twitch.tv/nasa
      The contest invites global creators of all ages to submit design ideas for a zero gravity indicator that will fly aboard the agency’s Artemis II test flight, the first crewed mission under NASA’s Artemis campaign.
      Up to 25 finalists, including entries from a K-12 student division, will be selected. The Artemis II crew will choose one design that NASA’s Thermal Blanket Lab will fabricate to fly alongside the crew in the Orion spacecraft.
      During this Twitch event, NASA experts will discuss the Moon Mascot Challenge while the artist incorporates live audience feedback into a sample design. Although the design example will not be eligible for the contest, it will demonstrate how challenge participants can develop their own zero gravity indicator designs. The example will be shared on the @NASAArtemis social media accounts following the Twitch event.
      The Artemis II test flight will take NASA astronauts Reid Wiseman, Victor Glover, and Christina Koch, and CSA (Canadian Space Agency) astronaut Jeremy Hansen on a 10-day journey around the Moon and back. The mission is another step toward missions on the lunar surface to help the agency prepare for future human missions to Mars.
      To learn more about NASA’s missions, visit:
      https://www.nasa.gov
      -end-
      Rachel Kraft
      Headquarters, Washington
      202-358-1600
      rachel.h.kraft@nasa.gov
      Share
      Details
      Last Updated May 12, 2025 EditorJessica TaveauLocationNASA Headquarters Related Terms
      Artemis 2 Earth's Moon Exploration Systems Development Mission Directorate Social Media View the full article
    • By NASA
      5 min read
      Preparations for Next Moonwalk Simulations Underway (and Underwater)
      Editor’s Note: The following is one of three related articles about the NASA Data Acquisition System and related efforts. Please visit Stennis News – NASA to access accompanying articles.
      A blended team of NASA personnel and contractors support ongoing development and operation of the NASA Data Acquisition System at NASA’s Stennis Space Center. Team members include, left to right: Andrew Graves (NASA), Shane Cravens (Syncom Space Services), Peggi Marshall (Syncom Space Services), Nicholas Payton Karno (Syncom Space Services), Alex Elliot (NASA), Kris Mobbs (NASA), Brandon Carver (NASA), Richard Smith (Syncom Space Services), and David Carver (NASA)NASA/Danny Nowlin Members of the NASA Data Acquisition System team at NASA’s Stennis Space Center evaluate system hardware for use in monitoring and collecting propulsion test data at the site.NASA/Danny Nowlin NASA software engineer Alex Elliot, right, and Syncom Space Services software engineer Peggi Marshall fine-tune data acquisition equipment at NASA’s Stennis Space Center by adjusting an oscilloscope to capture precise measurements. NASA/Danny Nowlin Syncom Space Services software test engineer Nicholas Payton Karno monitors a lab console at NASA’s Stennis Space Center displaying video footage of an RS-25 engine gimbal test, alongside data acquisition screens showing lab measurements. NASA/Danny Nowlin Just as a steady heartbeat is critical to staying alive, propulsion test data is vital to ensure engines and systems perform flawlessly.
      The accuracy of the data produced during hot fire tests at NASA’s Stennis Space Center near Bay St. Louis, Mississippi, tells the performance story.
      So, when NASA needed a standardized way to collect hot fire data across test facilities, an onsite team created an adaptable software tool to do it.
      “The NASA Data Acquisition System (NDAS) developed at NASA Stennis is a forward-thinking solution,” said David Carver, acting chief of the Office of Test Data and Information Management. “It has unified NASA’s rocket propulsion testing under an adaptable software suite to meet needs with room for future expansion, both within NASA and potentially beyond.”
      Before NDAS, contractors conducting test projects used various proprietary tools to gather performance data, which made cross-collaboration difficult. NDAS takes a one-size-fits-all approach, providing NASA with its own system to ensure consistency.
      “Test teams in the past had to develop their own software tools, but now, they can focus on propulsion testing while the NDAS team focuses on developing the software that collects data,” said Carver.
      A more efficient workflow has followed since the software system is designed to work with any test hardware. It allows engineers to seamlessly work between test areas, even when upgrades have been made and hardware has changed, to support hot fire requirements for the agency and commercial customers.
      With the backing and resources of the NASA Rocket Propulsion Test (RPT) Program Office, a blended team of NASA personnel and contractors began developing NDAS in 2011 as part of the agency’s move to resume control of test operations at NASA Stennis. Commercial entities had conducted the operations on NASA’s behalf for several decades.
      The NASA Stennis team wrote the NDAS software code with modular components that function independently and can be updated to meet the needs of each test facility. The team used LabVIEW, a graphical platform that allows developers to build software visually rather than using traditional text-based code.
      Syncom Space Services software engineer Richard Smith, front, analyzes test results using the NASA Data Acquisition System Displays interface at NASA’s Stennis Space Center while NASA software engineer Brandon Carver actively tests and develops laboratory equipment. NASA/Danny Nowlin NASA engineers, from left to right, Tristan Mooney, Steven Helmstetter Chase Aubry, and Christoffer Barnett-Woods are shown in the E-1 Test Control Center where the NASA Data Acquisition System is utilized for propulsion test activities. NASA/Danny Nowlin NASA engineers Steven Helmstetter, Christoffer Barnett-Woods, and Tristan Mooney perform checkouts on a large data acquisition system for the E-1 Test Stand at NASA’s Stennis Space Center. The data acquisition hardware, which supports testing for E Test Complex commercial customers, is controlled by NASA Data Acquisition System software that allows engineers to view real-time data while troubleshooting hardware configuration.NASA/Danny Nowlin NASA engineers Steven Helmstetter, left, and Tristan Mooney work with the NASA Data Acquisition System in the E-1 Test Control Center, where the system is utilized for propulsion test activities.NASA/Danny Nowlin “These were very good decisions by the original team looking toward the future,” said Joe Lacher, a previous NASA project manager. “LabVIEW was a new language and is now taught in colleges and widely used in industry. Making the program modular made it adaptable.”
      During propulsion tests, the NDAS system captures both high-speed and low-speed sensor data. The raw sensor data is converted into units for both real-time monitoring and post-test analysis.
      During non-test operations, the system monitors the facility and test article systems to help ensure the general health and safety of the facility and personnel.
      “Having quality software for instrumentation and data recording systems is critical and, in recent years, has become increasingly important,” said Tristan Mooney, NASA instrumentation engineer. “Long ago, the systems used less software, or even none at all. Amplifiers were configured with physical knobs, and data was recorded on tape or paper charts. Today, we use computers to configure, display, and store data for nearly everything.”
      Developers demonstrated the new system on the A-2 Test Stand in 2014 for the J-2X engine test project.
      From there, the team rolled it out on the Fred Haise Test Stand (formerly A-1), where it has been used for RS-25 engine testing since 2015. A year later, teams used NDAS on the Thad Cochran Test Stand (formerly B-2) in 2016 to support SLS (Space Launch System) Green Run testing for future Artemis missions.
      One of the project goals for the system is to provide a common user experience to drive consistency across test complexes and centers.
      Kris Mobbs, current NASA project manager for NDAS, said the system “really shined” during the core stage testing. “We ran 24-hour shifts, so we had people from across the test complex working on Green Run,” Mobbs said. “When the different shifts came to work, there was not a big transition needed. Using the software for troubleshooting, getting access to views, and seeing the measurements were very common activities, so the various teams did not have a lot of build-up time to support that test.”
      Following success at the larger test stands, teams started using NDAS in the E Test Complex in 2017, first at the E-2 Test Stand, then on the E-1 and E-3 stands in 2020.
      Growth of the project was “a little overwhelming,” Lacher recalled. The team maintained the software on active stands supporting tests, while also continuing to develop the software for other areas and their many unique requirements.
      Each request for change had to be tracked, implemented into the code, tested in the lab, then deployed and validated on the test stands.
      “This confluence of requirements tested my knowledge of every stand and its uniqueness,” said Lacher. “I had to understand the need, the effort to meet it, and then had to make decisions as to the priorities the team would work on first.”
      Creation of the data system and its ongoing updates have transformed into opportunities for growth among the NASA Stennis teams working together.
      “From a mechanical test operations perspective, NDAS has been a pretty easy system to learn,” said Derek Zacher, NASA test operations engineer. “The developers are responsive to the team’s ideas for improvement, and our experience has consistently improved with the changes that enable us to view our data in new ways.”
      Originally designed to support the RPT office at NASA Stennis, the software is expanding beyond south Mississippi to other test centers, attracting interest from various NASA programs and projects, and garnering attention from government agencies that require reliable and scalable data acquisition. “It can be adopted nearly anywhere, such as aerospace and defense, research and development institutions and more places, where data acquisition systems are needed,” said Mobbs. “It is an ever-evolving solution.”
      Read More Share
      Details
      Last Updated May 08, 2025 EditorNASA Stennis CommunicationsContactC. Lacy Thompsoncalvin.l.thompson@nasa.gov / (228) 688-3333LocationStennis Space Center Related Terms
      Stennis Space Center View the full article
    • By Space Force
      Chief Master Sgt. of the Space Force John F. Bentivegna outlined key strategic, operational and personnel initiatives during the Air and Space Forces Association's Warfighters in Action event, May 5.
      View the full article
  • Check out these Videos

×
×
  • Create New...