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Zero-Boil-Off Tank Experiments to Enable Long-Duration Space Exploration


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Zero-Boil-Off Tank Experiments to Enable Long-Duration Space Exploration

A grey space vehicle consisting of several attached sections; purple solar panels protrude from several of the sections.
Figure 1. The Gateway space station—humanity’s first space station around the Moon—will be capable of being refueled in space.
Credits:
NASA

Do we have enough fuel to get to our destination? This is probably one of the first questions that comes to mind whenever your family gets ready to embark on a road trip. If the trip is long, you will need to visit gas stations along your route to refuel during your travel. NASA is grappling with similar issues as it gets ready to embark on a sustainable mission back to the Moon and plans future missions to Mars. But while your car’s fuel is gasoline, which can be safely and indefinitely stored as a liquid in the car’s gas tank, spacecraft fuels are volatile cryogenic liquid propellants that must be maintained at extremely low temperatures and guarded from environmental heat leaks into the spacecraft’s propellant tank. And while there is already an established network of commercial gas stations in place to make refueling your car a cinch, there are no cryogenic refueling stations or depots at the Moon or on the way to Mars. Furthermore, storing volatile propellant for a long time and transferring it from an in-space depot tank to a spacecraft’s fuel tank under microgravity conditions will not be easy since the underlying microgravity fluid physics affecting such operations is not well understood. Even with today’s technology, preserving cryogenic fuels in space beyond several days is not possible and tank-to-tank fuel transfer has never been previously performed or tested in space.

Heat conducted through support structures or from the radiative space environment can penetrate even the formidable Multi-Layer Insulation (MLI) systems of in-space propellant tanks, leading to boil-off or vaporization of the propellant and causing tank self-pressurization. The current practice is to guard against over-pressurizing the tank and endangering its structural integrity by venting the boil-off vapor into space. Onboard propellants are also used to cool down the hot transfer lines and the walls of an empty spacecraft tank before a fuel transfer and filling operation can take place.  Thus, precious fuel is continuously wasted during both storage and transfer operations, rendering long-duration expeditions—especially a human Mars mission—infeasible using current passive propellant tank pressure control methods.

Zero-Boil-Off (ZBO) or Reduced Boil-Off (RBO) technologies provide an innovative and effective means to replace the current passive tank pressure control design. This method relies on a complex combination of active, gravity-dependent mixing and energy removal processes that allow maintenance of safe tank pressure with zero or significantly reduced fuel loss.

Zero Boil-off Storage and Transfer: A Transformative Space Technology

At the heart of the ZBO pressure control system are two proposed active mixing and cooling mechanisms to counter tank self-pressurization.  The first is based on intermittent, forced, subcooled jet mixing of the propellantand involves complex, dynamic, gravity-dependent interaction between the jet and the ullage (vapor volume) to control the condensation and evaporation phase change at the liquid-vapor interface. The second mechanism uses subcooled droplet injection via a spraybar in the ullage to control tank pressure and temperature. While the latter option is promising and gaining prominence, it is more complex and has never been tested in microgravity where the phase change and transport behavior of droplet populations can be very different and nonintuitive compared to those on Earth.

Although the dynamic ZBO approach is technologically complex, it promises an impressive advantage over the currently used passive methods. An assessment of one nuclear propulsion concept for Mars transport estimated that the passive boil-off losses for a large liquid hydrogen tank carrying 38 tons of fuel for a three-year mission to Mars would be approximately 16 tons/year. The proposed ZBO system would provide a 42% saving of propellant mass per year. These numbers also imply that with a passive system, all the fuel carried for a three-year Mars mission would be lost to boil-off, rendering such a mission infeasible without resorting to the transformative ZBO technology.

The ZBO approach provides a promising method, but before such a complex technological and operational transformation can be fully developed, implemented, and demonstrated in space, important and decisive scientific questions that impact its engineering implementation and microgravity performance must be clarified and resolved.

The Zero-Boil-Off Tank (ZBOT) Microgravity Science Experiments

The Zero Boil-off Tank (ZBOT) Experiments are being undertaken to form a scientific foundation for the development of the transformative ZBO propellant preservation method. Following the recommendation of a ZBOT science review panel comprised of members from aerospace industries, academia, and NASA, it was decided to perform the proposed investigation as a series of three small-scale science experiments to be conducted onboard the International Space Station. The three experiments outlined below build upon each other to address key science questions related to ZBO cryogenic fluid management of propellants in space.

Astronaut Joseph Acaba wearing glasses and a black T-shirt is half standing, suspended in microgravity next to the ZBOT experiment in the Microgravity Science Glovebox (MSG) Unit aboard the station. The MSG is a rectangular compartment tightly fitted with various components including the test tank, enclosed in a cylindrical metallic vacuum jacket, sitting on top of a close Fluid Supply Unit (FSU) that is used for fluid thermal conditioning. The space in MSG is further crowded by a reservoir, various entangled hoses and wiring system, a camera and a small laser unit used for Particle Imaging Velocimetry (PIV) diagnostics that measures and visualizes fluid motion in the tank.
Figure 3. Astronaut Joseph M. Acaba installing ZBOT Hardware in the Microgravity Science Glovebox aboard the International Space Station.
Credit: NASA

The ZBOT-1 Experiment: Self-Pressurization & Jet Mixing

The first experiment in the series was carried out on the station in the 2017-2018 timeframe. Figure 3 shows the ZBOT-1 hardware in the Microgravity Science Glovebox (MSG) unit of the station. The main focus of this experiment was to investigate the self-pressurization and boiling that occurs in a sealed tank due to local and global heating, and the feasibility of tank pressure control via subcooled axial jet mixing. In this experiment, the complicated interaction of the jet flow with the ullage (vapor volume) in microgravity was carefully studied. Microgravity jet mixing data was also collected across a wide range of scaled flow and heat transfer parameters to characterize the time constants for tank pressure reduction, and the thresholds for geyser (liquid fountain) formation, including its stability, and penetration depth through the ullage volume. Along with very accurate pressure and local temperature sensor measurements, Particle Image Velocimetry (PIV) was performed to obtain whole-field flow velocity measurements to validate a Computational Fluid Dynamics (CFD) model.

Four pictures side-by-side showing the results of a ZBOT pressure control jet mixing experiment in microgravity. The first picture shows a jet flow distinguished by blue, yellow, and red colored flow pathlines emanating from a flow nozzle in the bottom of the tank. The jet flow impinges on the ullage from below and deforms the ullage that was initially spherical into a shape that resembles the head of a bird with a pointed beak projected to the right. The second picture an experimental image captured by the Particle Imaging Velocimetry diagnostics. Tiny micron-sized particles illuminated by a laser sheet form shiny steak lines against a black background that displays the path of the fluid motion. The experimental pathlines resemble closely the CFD flow pathlines predicted by the CFD simulation as shown in the left-hand side picture. The third image shows a white-light image that captures the shape of the ullage positioned at the top left-hand side of the tank. This experimental image also shows the deformation of the ullage by the jet into a bird-head shaped figure confirming the shape and position of the ullage predicted by the CFD model. The last image shows the CFD prediction of the vortexed thermal structures that are created by the jet flow and represented by blue, yellow, and red temperature contours.
Figure 4. Validation of ZBOT CFD Model Predictions for fluid flow and deformation of a spherical ullage in microgravity by a subcooled liquid jet mixing against ZBOT experimental results: (a) Model prediction of ullage position and deformation and flow vortex structures during subcooled jet mixing; (b) PIV image capture of flow vortex structures during jet mixing; (c) Ullage deformation captured by white light imaging; and (d) CFD model depiction of temperature contours during subcooled jet mixing. (ZBOT-1 Experiment, 2018)
Credit: Dr. Mohammad Kassemi, Case Western Reserve University

Some of the interesting findings of the ZBOT-1experiment are as follows:

  1. Provided the first tank self-pressurization rate data in microgravity under controlled conditions that can be used for estimating the tank insulation requirements. Results also showed that classical self-pressurization is quite fragile in microgravity and nucleate boiling can occur at hotspots on the tank wall even at moderate heat fluxes that do not induce boiling on Earth. 
  2. Proved that ZBO pressure control is feasible and effective in microgravity using subcooled jet mixing, but also demonstrated that microgravity ullage-jet interaction does not follow the expected classical regime patterns (see Figure 4).
  3. Enabled observation of unexpected cavitation during subcooled jet mixing, leading to massive phase change at both sides of the screened Liquid Acquisition Device (LAD) (see Figure 5). If this type of phase change occurs in a propellant tank, it can lead to vapor ingestion through the LAD and disruption of liquid flow in the transfer line, potentially leading to engine failure.
  4. Developed a state-of-the-art two-phase CFD model validated by over 30 microgravity case studies (an example of which is shown in Figure 4). ZBOT CFD models are currently used as an effective tool for propellant tank scaleup design by several aerospace companies participating in the NASA tipping point opportunity and the NASA Human Landing System (HLS) program.
The left-hand picture shows an intact large hemispherical bubble (vapor ullage) at the top of the tank before the jet mixing starts. The right-hand picture shows the tank filled by numerous small sized bubbles that were created by an unexpected cavitation phase change phenomena when the pressure in the tank suddenly dropped due to the subcooled jet mixing operation.
Figure 5. White light image captures of the intact single hemispherical ullage in ZBOT tank before depressurization by the subcooled jet (left) and after subcooled jet mixing pressure collapse that led to massive phase change bubble generation due to cavitation at the LAD (right). (ZBOT-1 Experiment, 2018).
Credit: Dr. Mohammad Kassemi, Case Western Reserve University

The ZBOT-NC Experiment: Non-Condensable Gas Effects

Non-condensable gases (NCGs) are used as pressurants to extract liquid for engine operations and tank-to-tank transfer. The second experiment, ZBOT-NC will investigate the effect of NCGs on the sealed tank self-pressurization and on pressure control by axial jet mixing. Two inert gases with quite different molecular sizes, Xenon, and Neon, will be used as the non-condensable pressurants. To achieve pressure control or reduction, vapor molecules must reach the liquid-vapor interface that is being cooled by the mixing jet and then cross the interface to the liquid side to condense.

This study will focus on how in microgravity the non-condensable gases can slow down or resist the transport of vapor molecules to the liquid-vapor interface (transport resistance) and will clarify to what extent they may form a barrier at the interface and impede the passage of the vapor molecules across the interface to the liquid side (kinetic resistance). By affecting the interface conditions, the NCGs can also change the flow and thermal structures in the liquid.

ZBOT-NC will use both local temperature sensor data and uniquely developed Quantum Dot Thermometry (QDT) diagnostics to collect nonintrusive whole-field temperature measurements to assess the effect of the non-condensable gases during both self-pressurization heating and jet mixing/cooling of the tank under weightlessness conditions. This experiment is scheduled to fly to the International Space Station in early 2025, and more than 300 different microgravity tests are planned. Results from these tests will also enable the ZBOT CFD model to be further developed and validated to include the non-condensable gas effects with physical and numerical fidelity.

The ZBOT-DP Experiment: Droplet Phase Change Effects

ZBO active pressure control can also be accomplished via injection of subcooled liquid droplets through an axial spray-bar directly into the ullage or vapor volume. This mechanism is very promising, but its performance has not yet been tested in microgravity. Evaporation of droplets consumes heat that is supplied by the hot vapor surrounding the droplets and produces vapor that is at a much lower saturation temperature. As a result, both the temperature and the pressure of the ullage vapor volume are reduced. Droplet injection can also be used to cool down the hot walls of an empty propellant tank before a tank-to-tank transfer or filling operation. Furthermore, droplets can be created during the propellant sloshing caused by acceleration of the spacecraft, and these droplets then undergo phase change and heat transfer. This heat transfer can cause a pressure collapse that may lead to cavitation or a massive liquid-to-vapor phase change. The behavior of droplet populations in microgravity will be drastically different compared to that on Earth.

The ZBOT-DP experiment will investigate the disintegration, coalescence (droplets merging together), phase change, and transport and trajectory characteristics of droplet populations and their effects on the tank pressure in microgravity. Particular attention will also be devoted to the interaction of the droplets with a heated tank wall, which can lead to flash evaporation subject to complications caused by the Liedenfrost effect (when liquid droplets propel away from a heated surface and thus cannot cool the tank wall). These complicated phenomena have not been scientifically examined in microgravity and must be resolved to assess the feasibility and performance of droplet injection as a pressure and temperature control mechanism in microgravity.

Back to Planet Earth

This NASA-sponsored fundamental research is now helping commercial providers of future landing systems for human explorers. Blue Origin and Lockheed Martin, participants in NASA’s Human Landing Systems program, are using data from the ZBOT experiments to inform future spacecraft designs.

Cryogenic fluid management and use of hydrogen as a fuel are not limited to space applications. Clean green energy provided by hydrogen may one day fuel airplanes, ships, and trucks on Earth, yielding enormous climate and economic benefits. By forming the scientific foundation of ZBO cryogenic fluid management for space exploration, the ZBOT science experiments and CFD model development will also help to reap the benefits of hydrogen as a fuel here on Earth. 

PROJECT LEAD

Dr. Mohammad Kassemi (Dept Mechanical & Aerospace Engineering, Case Western Reserve University)

SPONSORING ORGANIZATION

Biological and Physical Sciences (BPS) Division, NASA Science Mission Directorate (SMD)

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      For five decades and counting, the versatile NASA Stennis test stands have been used for stage, engine, and component testing on multiple NASA and commercial projects.
      A Sept. 25, 2012, aerial image shows the three propulsion test areas at NASA’s Stennis Space Center – the E Test Complex (with 12 active test cell positions capable of component, engine, and stage test activities) in the foreground, the A Test Complex (featuring the Fred Haise, A-2, and A-3 stands for large engine testing) in the middle, and the Thad Cochran Test Stand (B-1/B-2) that can support both engine and stage testing in the background.NASA/Stennis The Fred Haise Test Stand (formerly the A-1 Test Stand), pictured on Oct. 6, 2020, at NASA’s Stennis Space Center, tests RS-25 flight engines to help power NASA’s powerful SLS (Space Launch System). NOTE: Right click on photo to open full image in new tab.NASA/Stennis An image shows the A-2 Test Stand at NASA’s Stennis Space Center – then-Mississippi Test Facility – on April 17, 1966. Less than a week later, south Mississippi would be fully ushered into the Apollo era with the site’s first-ever hot fire test. NOTE: Right click on photo to open full image in new tab.NASA/Stennis An image shows the A-3 Test Stand at NASA’s Stennis Space Center on March 29, 2013. The test stand area now is under lease to Rocket Lab for commercial operations. NOTE: Right click on photo to open full image in new tab.NASA/Stennis An image shows the Thad Cochran Test Stand (B-1/B-2) at NASA’s Stennis Space Center on Dec. 31, 2014, during buildout for testing the core stage of NASA’s SLS (Space Launch System) rocket. NASA/Stennis An aerial image shows the Thad Cochran Test Stand (B-1/B-2) at NASA’s Stennis Space Center on Feb. 22, 2017, following core stage buildout of the test stand for future SLS (Space Launch System) testing. NASA/Stennis Three NASA Stennis stands – Fred Haise (formerly the A-1 Test Stand), A-2, and Thad Cochran (B-1/B-2) – date to the 1960s, when they were built to test Saturn V rocket stages for Apollo missions to the Moon. The Fred Haise and A-2 stand were single-position stands for testing one Saturn V second stage at a time. The Thad Cochran featured two positions – (B-1 and B-2) – that could each house a Saturn V first stage, although only the B-2 position was used during Apollo testing.
      When the Apollo Program ended, the Fred Haise, A-2, and Thad Cochran (B-1) stands were modified to test single engines rather than rocket stages. All three were used in subsequent years to test space shuttle main engines and others.
      Meanwhile, the Thad Cochran (B-2) stand was maintained for full stage testing. The space shuttle Main Propulsion Test Article was tested on the stand, as was the Common Core Booster for the Delta IV rocket. Most recently, the stand was used to test the first SLS (Space Launch System) stage that helped launch the Artemis I mission in 2022.
      In 2024, the Fred Haise Test Stand is dedicated to RS-25 engine testing for NASA’s Artemis initiative. Every RS-25 engine that will help launch an SLS rocket during Artemis will be tested on the stand. The A-2 stand has been leased to Relativity Space, which is modifying it to support stage testing for its new rocket. In 2023, the Thad Cochran (B-1) stand concluded more than 20 years of RS-68 testing for Aerojet Rocketdyne (now known as L3Harris) and now is open for commercial use. The Thad Cochran (B-2) stand is being prepared to test NASA’s new SLS exploration upper stage before it flies on a future Artemis mission.
      “When you think about the work at NASA Stennis, this is a place that helps write history,” Vander said. “And in a sense, these test stands are timeless, still operating as designed 60 years after they were built, so there is more history yet to come.”
      NASA Stennis also constructed a fourth large test structure in the 2010s. The A-3 Test Stand is uniquely designed to simulate high altitudes up to 100,000 feet for testing engines and stages that need to fire in space. Rocket Lab currently leases the A-3 Test Stand area for construction of its Archimedes Test Complex.
      Crews deliver the first RS-25 flight engine, engine No. 2059, to the Fred Haise Test Stand (formerly the A-1 Test Stand) at NASA’s Stennis Space Center on Nov. 4, 2015. The engine was tested to certify it for use on NASA’s powerful SLS (Space Launch System) rocket. NASA/Stennis An image shows a space shuttle main engine test on the A-2 Test Stand at NASA’s Stennis Space Center on July 21, 2003. NASA/Stennis The A-3 Test Stand, designed to test fire next-generation engines at simulated altitudes up to 100,000 feet, undergoes an activation test on Feb. 24, 2014.NASA/Stennis NASA Stennis also operates a smaller test area to conduct component, subsystem, and system level testing. The area is now known as the E Test Complex and features four facilities, all developed from the late 1980s to the early 1990s.
      Construction of the E-1 Test Stand, then known as the Component Test Facility, began to support a joint project involving NASA and the U.S. Air Force project. Although the project was canceled, a second joint endeavor allowed completion of the test facility.
      Development of the E-2 Test Stand, originally known as the High Heat Flux Facility, began to support the National Aerospace Plane project. Following cancelation of the project, the facility was completed to support testing for component and engine development efforts.
      An E-3 Test Facility was constructed to support various component and small/subscale engine and booster test projects. Relativity Space leased a partially developed E-4 test area in 2018 and has since completed construction to support its commercial testing.
      All in all, the E Test Complex stands feature 12 active cells capable of various component and engine testing. The versatility of the complex infrastructure and test team allows it to support test projects for a range of commercial aerospace companies, large and small. Currently, both E-2 cells 1 and 2 are leased to Relativity Space through 2028.
      An aerial image shows the E-1 Test Stand at NASA’s Stennis Space Center on May 19, 2015. The versatile four-stand E Test Complex includes 12 active test cell positions capable of various component, engine, and stage test activities. NASA/Stennis An aerial image shows the E-3 test area at NASA’s Stennis Space Center on May 19, 2015. The versatile four-stand E Test Complex includes 12 active test cell positions capable of various component, engine, and stage test activities. NASA/Stennis An aerial image shows the E-2 Test Stand (Cell 1) at NASA’s Stennis Space Center on May 19, 2015. The versatile four-stand E Test Complex includes 12 active test cell positions capable of various component, engine, and stage test activities. NASA/Stennis “These facilities really do not exist anywhere else in the United States,” said Kevin Power, assistant director, Office of Project Management in the NASA Stennis Engineering and Test Directorate.  “Customers come to us with requirements for certain tests of an article, and we look at what is the best place to test it based on the facility infrastructure. We have completed component level testing, all the way up to full engines.”
      The list of companies who have conducted – or are now conducting – propulsion projects in the E Test Complex reads like a who’s who of commercial aerospace leaders.
      “The E Complex illustrates the NASA Stennis story,” Power said. “We have very valuable infrastructure and resources, chief of which is the test team, who adapt to benefit NASA and meet the needs of the growing commercial aerospace industry.”
      For information about NASA’s Stennis Space Center, visit:
      Stennis Space Center – NASA
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      Last Updated Nov 13, 2024 EditorNASA Stennis CommunicationsContactC. Lacy Thompsoncalvin.l.thompson@nasa.gov / (228) 688-3333LocationStennis Space Center Related Terms
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      Note: The following article is part of a series highlighting propulsion testing at NASA’s Stennis Space Center. To access the entire series, please visit: https://www.nasa.gov/feature/propulsion-powering-space-dreams/.
      An aerial image from 1965 shows the dual flame trenches of the Thad Cochran Test Stand (B-1/B-2) under construction at NASA’s Stennis Space Center (then known as Mississippi Test Operations) taking shape.NASA/Stennis Since the United States sent the first humans to the Moon more than 60 years ago, NASA’s Stennis Space Center near Bay St. Louis, Mississippi, has answered the call to help power the nation’s space dreams.  
      “History shows NASA Stennis is the country’s premier rocket engine test site and the go-to place for propulsion testing,” NASA Stennis Director John Bailey said. “It started with Apollo and continued through space shuttle. Now, we are going back to the Moon and beyond with Artemis – and it all comes through NASA Stennis.” 
      As the nation raced to send the first humans to the Moon, NASA selected a remote location in Hancock County, Mississippi, in October 1961 to test the needed rocket stages. Thanks to a massive construction project, the site conducted its first Saturn V rocket stage test in April 1966. In the next four-plus years, NASA Stennis tested 27 Saturn V stages, including those that launched 12 astronauts to walk on the Moon.  
      “Talking to people working here during those years, you hear how much they believed in the mission,” said Joe Schuyler, director of the NASA Stennis Engineering and Test Directorate. “Their hard work helped America reach the Moon and showed us the possibilities for NASA Stennis.”   
      Construction workers bring down a tree during the early days of construction for NASA’s Stennis Space Center. Tree-cutting to start what was the largest construction project in Mississippi – and one of the largest in the United States – at the time began May 17, 1963.NASA/Stennis NASA Stennis (then known as the Mississippi Test Facility) conducts its first-ever test firing – a 15-second hot fire of the Saturn V S-II-C second stage prototype – on the A-2 Test Stand on April 23, 1966.NASA/Stennis An aerial image from early 1967 shows the completed A-2 Test Stand in the foreground and the Thad Cochran Test Stand (B-1/B-2) in the background at NASA’s Stennis Space Center, then known as the Mississippi Test Facility.NASA/Stennis NASA officials view the first space shuttle main engine test on the Fred Haise Test Stand (formerly the A-1 Test Stand) at NASA’s Stennis Space Center (then known as National Space Technology Laboratories) on May 19, 1975.NASA/Stennis A 1979 image offers a close-up view of a space shuttle main propulsion test article hot fire on the B-2 side of the Thad Cochran Test Stand at NASA’s Stennis Space Center (then known as National Space Technology Laboratories). Main propulsion test article testing involved installing a shuttle fuel tank, a mockup of the shuttle orbiter and the vehicle’s three-engine configuration on the stand, then firing all three engines simultaneously, as would be done during an actual launch.NASA/Stennis As Apollo missions neared an end, plans were underway to drastically reduce the NASA Stennis footprint. Enter the space shuttle. NASA considered three locations to test engines for its new reusable vehicle before selecting NASA Stennis on March 1, 1970, ensuring the center’s future for the next several decades.  
      Space shuttle main engine testing proved challenging as the site transitioned from handling full rocket stages to firing single engines. “A big part of the challenge was the fact that teams were testing an entire engine from the very start,” NASA Test Operations Chief Maury Vander said. “Typically, you begin testing components, then progress to a full engine. Teams had a lot to learn in real time.” 
      NASA Stennis teams also tested the shuttle Main Propulsion Test Article with three engines firing simultaneously. The testing was particularly critical given the first shuttle mission would carry astronauts. 
      NASA Stennis teams worked diligently to demonstrate the shuttle system would operate safely, an effort characterized as one of the site’s finest hours. Following the first shuttle mission in 1981, astronauts Robert Crippen and John Young visited the south Mississippi site. “The effort that you contributed made it possible for us to sit back and ride,” Crippen told NASA Stennis employees. 
      From 1975 to 2009, NASA Stennis tested every main engine to help power 135 shuttle missions that enabled historic missions, such as those that deployed and repaired the Hubble Space Telescope and assembled the International Space Station, enabling its many scientific experiments and spinoff technologies. The site also tested every engine and component upgrade and helped troubleshoot performance issues. It led test campaigns following shuttle accidents to help ensure safe returns to flight. In total, the site conducted 2,307 tests for 820,475.68 seconds of accumulated hot fire. 
      NASA conducts the final test of a space shuttle main engine on the A-2 Test Stand at NASA’s Stennis Space Center on July 29, 2009. The Space Shuttle Program concluded two years later with the STS-135 shuttle mission.  NASA / Stennis An on-stand camera offers a closeup view of the first test of an RS-25 engine on the Fred Haise Test Stand (formerly the A-1 Test Stand) at NASA’s Stennis Space Center on Jan. 9, 2015. RS-25 engines power the core stage of NASA’s powerful SLS (Space Launch System) rocket.NASA/Stennis Crews at NASA’s Stennis Space Center install the first core stage of NASA’s powerful SLS (Space Launch System) on the B-2 side of the Thad Cochran Test Stand on Jan. 21-22, 2020. Following testing, the stage would help launch the Artemis I mission in November 2022.NASA/Stennis NASA conducts a full-duration RS-25 hot fire April 3, 2024, on the Fred Haise Test Stand at NASA’s Stennis Space Center, achieving a major milestone for future Artemis flights of NASA’s SLS (Space Launch System) rocket. It marked the final hot fire of a 12-test series to certify production of new RS-25 engines by lead contractor L3Harris (formerly known as Aerojet Rocketdyne) to help power NASA’s SLS rocket on Artemis missions to the Moon and beyond, beginning with Artemis V.NASA/Stennis Even as NASA Stennis tested main engines to power shuttle missions, the site led in testing next-generation engines, including the Fastrac, XRS-2200 linear aerospike, and J-2X. It also developed its E Test Complex, with multiple test stands and cells, to support a range of component and engine test projects, including those of commercial aerospace companies.
      A landmark agreement between NASA Stennis and Aerojet Rocketdyne (now known as L3Harris) in 1998 marked the site’s first test partnership with such a company. “That was the starting point,” said Vander. “Today, we are a preferred partner for multiple companies and test projects, large and small.” 
      NASA Stennis also is testing RS-25 engines and related systems to help power NASA’s SLS (Space Launch System) rocket on Artemis missions to the Moon. When the agency travels to Mars, it is expected the missions will launch with engines tested at the Mississippi site as well. 
      “The Gulf Coast of Mississippi helped achieve our space dreams of the past, and NASA Stennis continues supporting today’s dreams,” Bailey said. “It is a true testament to the expertise and dedication of our entire team and the incredible support of surrounding communities and the whole state.” 
      For information about NASA’s Stennis Space Center, visit: 
      Stennis Space Center – NASA 
      Share
      Details
      Last Updated Nov 13, 2024 EditorNASA Stennis CommunicationsContactC. Lacy Thompsoncalvin.l.thompson@nasa.gov / (228) 688-3333LocationStennis Space Center Related Terms
      Stennis Space Center Explore More
      5 min read NASA Stennis – An Ideal Place for Commercial Companies
      Article 13 mins ago 4 min read NASA Stennis Propulsion Testing Contributes to Artemis Missions
      Article 14 mins ago 5 min read NASA Stennis Test Team Supports Space Dreams with Proven Expertise
      Article 14 mins ago Keep Exploring Discover Related Stennis Topics
      Propulsion Test Engineering
      NASA Stennis Front Door
      Multi-User Test Complex
      Doing Business with NASA Stennis
      View the full article
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