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SLS Booster Fired up to Test Improved Design for Future Artemis Missions

A team of NASA and Northrop Grumman engineers fired a 2-foot-diameter, subscale solid rocket booster on Dec. 2, 2021, at NASA’s Marshall Space Flight Center in Huntsville, Alabama. This test, conducted in Marshall’s East Test Area, was the second of three tests supporting the Booster Obsolescence and Life Extension (BOLE) program, which will have an upgraded design to power the evolved configuration of the Space Launch System (SLS) rocket on flights after Artemis VIII.

NASA engineers successfully completed a 24-inch diameter subscale solid rocket test on Dec. 2, 2021, at NASA’s Marshall Space Flight Center in Huntsville, Alabama, in the East Test Area. The sub-scale motor produced 76,400 pounds of thrust during the hot fire test. This test was the first of two tests supporting the Booster Obsolescence and Life Extension (BOLE) development effort that includes a new motor design for upcoming Artemis missions after Artemis VIII. This 334-inch motor was the longest subscale motor tested to date.

The BOLE booster will be a larger and more powerful solid rocket motor than the current SLS solid rocket booster. The boosters for the first eight flights of the Artemis program repurpose the steel booster cases and parts from the Space Shuttle Program with an upgraded design. The BOLE booster will implement a composite case design, replace obsolete parts with newer components, and improve the booster’s design and performance.

This test focused on the booster motors, which provide the majority of the power to launch SLS. Unlike previous subscale motor tests, this marked the first time the team could evaluate insulation and nozzle on one motor rather than two configurations, one for the nozzle and one for the insulation. During this subscale test, the motor produced 76,400 pounds of thrust.

The original test design had two segments, each 9 feet long. To get a more characteristic thrust profile, a 4.5-foot-long segment was added to the test article, totaling nearly 28 feet and making this the longest subscale motor tested to date. In addition to the added half segment, a new propellant, aft dome design, and nozzle design are included in the BOLE motor development program that will become part of the Block 2 evolved rocket.

During the test, three different internal case insulation formulations were evaluated in the aft dome. The performance results of these materials will aid in selecting a final formulation for the first full-scale test fire of the BOLE booster. As the team completes the final design for the full-scale motor, this test is an important step in learning how materials will perform at the higher pressure and performance expected for the BOLE motor as compared to current motors.

The third test of the subscale motor is currently scheduled for spring 2022 at Marshall, followed by the first full-scale BOLE motor test, tentatively scheduled for spring 2024 at Northrop Grumman’s test facility in Utah. Northrop Grumman, lead contractor for the booster, helped conduct the Marshall test and will be assisting with data evaluation.

Final Piece of Rocket Hardware Added to Artemis I Stack

Final OSA stacked on top of the ICPS — After successfully completing the integrated modal test, technicians removed the Space Launch System (SLS) rocket’s Orion stage adapter structural test article and the Mass simulator for Orion. Then, they moved the Orion stage adapter flight hardware to the Vehicle Assembly Building at NASA’s Kennedy Space Center in Florida. On Oct. 9, the Orion stage adapter was connected to the top of the Interim Cryogenic Propulsion Stage (ICPS) that provides the power to send Orion to the Moon. Soon, Orion, which rides on top of SLS, will be stacked to complete the Artemis I spaceship. Artemis I is the first integrated flight of SLS and Orion. This uncrewed flight test will be followed by Artemis II, which will be the first mission to send astronauts on a mission to orbit the Moon.

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The last piece of Space Launch System (SLS) rocket hardware has been added to the stack at NASA’s Kennedy Space Center in Florida. Crews with NASA’s Exploration Ground Systems and contractor Jacobs added the Orion stage adapter to the top of the rocket inside the spaceport’s Vehicle Assembly Building. To complete the Artemis I stack, crews will soon add the Orion spacecraft and its launch abort system on top of Orion stage adapter.

The Orion stage adapter, built at NASA’s Marshall Space Flight Center in Huntsville, Alabama connects Orion to the Interim Cryogenic Propulsion Stage (ICPS), which was built by Boeing and United Launch Alliance at ULA’s factory in Decatur, Alabama. During the mission, the ICPS will fire one RL10 engine in a maneuver called trans-lunar injection, or TLI, to send Orion speeding toward the Moon.

As Orion heads to the Moon for its mission, the ICPS will separate from Orion and then deploy 10 secondary payloads that are riding to space inside the Orion stage adapter. These CubeSats have their own propulsion systems that will take them on missions to the Moon and other destinations in deep space.

While the ICPS and Orion stage adapter are making it possible for SLS to send its first science payloads to space on this uncrewed mission, they only will be used for the first three Artemis missions. The Exploration Upper Stage (EUS), a more powerful stage with four RL10 engines, will be used on future Artemis missions. The EUS can send 83,000 pounds to the Moon, which is 40 percent more weight than the ICPS. The EUS makes it possible to send Orion, astronauts, and larger and heavier co-manifested payloads to the Moon.

Artemis I will be followed by a series of increasingly complex missions. With Artemis, NASA will land the first woman and the first person of color on the lunar surface and establish long-term exploration at the Moon in preparation for human missions to Mars. SLS and NASA’s Orion spacecraft, along with the commercial human landing system and the Gateway in orbit around the Moon, are NASA’s backbone for deep space exploration. SLS is the only rocket that can send Orion, astronauts, and supplies to the Moon in a single mission.

NASA Team Preparing Hardware for Future Moon Rockets

Technicians and engineers continue to make progress manufacturing core stages that will help power NASA’s Space Launch System (SLS) rocket for its second and third flights. NASA and Boeing, the lead contractor for the core stage, are in the process of conducting one of the biggest Artemis II milestones: assembling the top half of the core stage.

The 212-foot tall core stage for the SLS rocket is the largest rocket stage NASA has ever produced. The five individual elements that make up the core stage – the forward skirt, liquid oxygen tank, intertank, liquid hydrogen tank, and the engine section – are manufactured and assembled at NASA’s Michoud Assembly Facility in New Orleans. Together, the elements will supply propellant, vehicle control, and power to the four RS-25 engines at the bottom of the stage to produce more than 2 million pounds of thrust to send missions to the Moon.

The team manufactures every SLS core stage in Michoud’s 43-acre building which provides more than enough space for crews to work in tandem to build the core stages for Artemis II and Artemis III, the second and third flights of the SLS rocket and the first crewed missions of NASA’s Artemis program.

It takes teamwork to build a super heavy-lift rocket. Look behind the scenes at the work being done at NASA’s rocket factory:

The Artemis II Intertank is lifted into the Cell D of the VAB at NASA Michoud Assembly Facility on Friday, March 19, 2021.

Coming together to build the upper part of the rocket

After all the core stage’s large five structures are built and outfitted, these structures are connected during three major joining operations. For first one, the forward or upper parts of the core stage are joined together for the first time. First, teams move the intertank into an assembly area and connect it to the liquid oxygen tank, and then they add the forward skirt to form the entire upper part of the SLS core stage.

Crews with NASA and Boeing, the core stage prime contractor, recently moved the Artemis II intertank, above, to the assembly area where the three components will be stacked.

The Artemis II forward skirt, pictured above, has been outfitted and is ready for integration with the other large core stage structures. The forward skirt houses flight computers, cameras, and avionics systems. It is located at the very top of the core stage and connects to the upper part of the rocket.

Moving through the manufacturing process

The core stage has two huge cryogenic liquid propellant tanks that collectively hold more than 733,000 gallons of liquid propellant to help launch the Space Launch System rocket to the Moon. Moving the immense hardware, especially the two propellant tanks, around the factory is a delicate process.

Teams carefully orchestrate every step of every lift and transport inside and outside the rocket factory. To safely and securely move hardware, they use special transporters and cranes that are designed to contain, hold, and handle the weight of each element. Above, teams move the more than 130-foot-tall liquid hydrogen tank to the same area as the liquid oxygen tank. Both propellant tanks will be used for Artemis II.

The aisles at Michoud are extra-wide to ensure large hardware can be transported throughout the factory. For the next phase of manufacturing, crews recently moved the boat-tail, a fairing-like cover that attaches to the engine section on the bottom of the core stage. The boat-tail is shown in the image foreground, and the engine section for Artemis II can be seen in the background covered with scaffolding. The four RS-25 engines for the SLS rocket will be mounted inside the engine section, and the boat-tail helps to protect and cover most of the four RS-25 engines’ critical systems.

Fusion Weld on H3 R2

It’s all in the details

As crews prepare the core stage elements that will be used for Artemis II for assembly and integration, the hardware for Artemis III is being welded in other areas of the factory. Engineers and technicians use friction-stir welding methods to connect the panels that make up each piece of hardware together and build larger structures. Fusion welding is traditional welding, and it uses heat to plug holes left by machines welding the larger pieces as well as for any necessary weld repairs.

Welding processes help to create the shells, or outside, of the core stage structures. Above, the engine section for Artemis III comes together in the Vertical Weld Center at Michoud. They are made by connecting panels such as the one in the front of this image. The engine section has been completed and moved to another part of the factory. One of the biggest tasks ahead, is outfitting it with a network of internal components and systems that connect to the RS-25 engines.

In May, the core stage team will begin work on the Artemis IV core stage, so three stages will be under construction at the same time. Because of the factory’s size, state-of-the-art equipment, and manufacturing processes, skilled workers can produce multiple rocket stages to power NASA’s next-generation Moon missions through the Artemis program.

NASA is working to land the first woman and the first person of color on the Moon. SLS and Orion, along with the human landing system and the Gateway in orbit around the Moon, are NASA’s backbone for deep space exploration. SLS is the only rocket that can send Orion, astronauts, and supplies to the Moon in a single mission.

Artemis I Core Stage Being Readied for Shipment to Kennedy

The Space Launch System (SLS) core stage Green Run team has reviewed extensive data and completed inspections that show the rocket’s core stage and engines are in excellent condition after the full-duration Green Run hot fire test on Mar. 18.

This test at NASA’s Stennis Space Center near Bay St. Louis, Mississippi allowed the team to obtain data to meet all the hot fire test objectives. This second hot fire test with the core stage flight hardware that will launch the Artemis I mission to the Moon was described as “flawless” by the test team that included NASA and prime contractors Boeing and Aerojet Rocketdyne. The team encountered no issues during the test that started with powering up the core stage on Mar. 16.

While analyzing data, the team refurbished the core stage in preparations for shipping it this month to NASA’s Kennedy Space Center in Florida for the Artemis I launch. Refurbishment activities included drying the RS-25 engines and making expected repairs to the engines and the thermal protection system on the core stage.

This week, the team powered up the core stage and loaded the flight software that will be used for the Artemis I mission. Now, they are disconnecting systems that connect the stage to the B-2 Test Stand. Next, the stage will undergo final shipping preparations before it is lifted out of the stand and placed on the Pegasus barge.

Check back at this blog for updates as the Artemis I core stage prepares for its voyage to Kennedy.

NASA Begins Major Assembly of Rocket Stage for First Crewed Artemis Mission

The NASA team is moving parts of the Space Launch System rocket to begin assembly of the forward, or upper part, of the rocket’s core stage for the Artemis II Moon mission. On March 19, the intertank was moved to the vertical assembly area at NASA’s Michoud Assembly Facility in New Orleans where the core stage is manufactured. The intertank flight hardware is part of the upper portion of the core stage that will help power Artemis II, the second flight of the deep space rocket and the first crewed lunar mission of NASA’s Artemis program.

The Space Launch System rocket’s intertank is the first piece of the upper part of the core stage to be moved for stacking in the vehicle assembly area at NASA’s Michoud Assembly Facility in New Orleans.

To form the massive, 212-foot-tall core stage for the agency’s Moon rocket, five major structures are joined together: the forward skirt, liquid oxygen tank, intertank, liquid hydrogen tank, and engine section. NASA and Boeing, the core stage prime contractor, are preparing to connect three structures together to create the forward assembly of the core stage. The process of stacking and assembling the forward skirt, liquid oxygen tank, and intertank is called the forward join, and it is the first major vertical integration of hardware for the Artemis II core stage. The intertank is first installed in a vertical stacking cell at Michoud. Later, teams will move the liquid oxygen tank and forward skirt to the same area to stack the three structures together.

Infographic on forward join The intertank contains avionics that are the “brains” of the rocket. It also serves as one of the main attach points for the twin solid rocket boosters that work with the core stage to send SLS to space. The core stage will supply propellant and power to the four RS-25 engines at the bottom of the stage to produce the remaining 2 million pounds of thrust needed to send the Artemis II mission to orbit.

NASA is working to land the first woman and the next man on the Moon. SLS and Orion, along with ground systems at Kennedy, the human landing system and the Gateway in orbit around the Moon, are NASA’s backbone for deep space exploration. SLS is the only rocket that can send Orion, astronauts, and supplies to the Moon in a single mission. (NASA image)

Green Run Update: Tanking Complete for Rocket Hot Fire Test

Engineers have completed tanking for the hot fire test of NASA’s Space Launch System (SLS) rocket core stage at the agency’s Stennis Space Center, and the countdown is proceeding normally.

The liquid hydrogen tank holds 537,000 gallons of liquid hydrogen, cooled to minus 423 degrees Fahrenheit. The liquid oxygen tank holds 196,000 gallons of liquid oxygen, cooled to minus 297 degrees Fahrenheit. After tanking is complete, the team will continue chilling down the liquid oxygen propellant to condition it before the hot fire. While they are conditioning the liquid oxygen, they replenish the liquid hydrogen as it boils off due to temperature fluctuations as the propellant is loaded. The tanks can be loaded up to 22 times for testing and launches.

This image shows the core stage liquid hydrogen tank at NASA’s Michoud Assembly Facility in New Orleans where it and the rest of the core stage where built and assembled. The flight core stage for the Artemis I mission is being tested today. Boeing, the prime contractor for the core stage, has already manufactured liquid hydrogen tanks for the Artemis II and Artemis III lunar missions.

This part of the test timeline is also important as it pertains to simulating launch. During a launch, many activities will be happening on the pad at this time, such as loading the crew. The hot fire test provides an opportunity to demonstrate that the core stage can remain in a stable configuration and be replenished as needed before engine firing to launch the rocket.

Learn more about Green Run, and check back at this blog for updates on the SLS core stage hot fire test.

Green Run Update: Power Up Started for Hot Fire Test

Engineers have initiated power up of the flight computes and avionics for the Artemis I core stage. This begins the countdown for the hot fire test with the core stage of NASA’s Space Launch System (SLS) rocket scheduled for Thursday, March 18.

Before the test, the management team in the Test Control Center at the B test complex will provide approval to proceed into the test. One of the first actions on hot fire day will be to load the stage’s huge tanks with more than 700,000 gallons of propellant. Six barges filled with liquid hydrogen and oxygen will supply the propellant to the B-2 test stand at NASA’s Stennis Space Center near Bay St. Louis, Mississippi, where the Green Run tests are taking place. The engines use cryogenic, or supercooled, liquid hydrogen as fuel and liquid oxygen as oxidizer to create combustion.

To fill each of the six barges, three for liquid oxygen and three for liquid hydrogen, it required 18 to 20 tanker trucks worth of propellant. The barges are towed by tug from a fuel depot at Stennis to the B-2 stand.

In this video, SLS Stages Manager Julie Bassler, describes avionics and flight software testing conducted in the Systems Integration Laboratory at NASA’s Marshall Space Flight Center in Huntsville, Alabama, to support Green Run. The computers and avionics are the “brains” of the rocket, and they control the core stage systems during the test, just like they will be required to control the rocket during the Artemis I flight.

Learn more about Green Run, and check back at this blog for updates on the SLS core stage hot fire test.

Green Run Update: NASA Targets March 18 for SLS Hot Fire Test

NASA is targeting Thursday, March 18 for the second hot fire of the Space Launch System (SLS) rocket’s core stage at NASA’s Stennis Space Center near Bay St. Louis, Mississippi.

After performing tests to demonstrate that a recently repaired liquid oxygen pre-valve was working, the team has continued to prepare the core stage, its four RS-25 engines, and the B-2 test stand for the second hot fire at Stennis. Later this week, the team will power up the core stage again and do a final check of all its systems. Then, on March 16, two days before the test, they will power up the stage, starting the clock for the second hot fire.

Test Like you Fly Infographic — This infographic explains the objectives of the Space Launch System rocket’s core stage Green Run test series.

This hot fire is the last test before the Artemis I core stage is shipped to the agency’s Kennedy Space Center for assembly and integration with the rest of the rocket’s major elements and the Orion spacecraft. Exploration Ground Systems teams at Kennedy have stacked all parts of the solid rocket boosters for Artemis I in the Vehicle Assembly Building and are finishing up booster assembly. After the core stage arrives, it will be lifted and placed between the two boosters and attached at the core stage engine and intertank sections. Other parts of the rocket and the Orion spacecraft are also at Kennedy and are being prepared for final assembly and integration.

NASA’s SLS rocket is the most powerful rocket in the world, built to send both astronauts aboard Orion and supplies on missions to the Moon and beyond. The Green Run is a comprehensive test of the SLS core stage, a complex new rocket stage that not only includes four RS-25 engines and enormous propellant tanks that hold more than 700,000 gallons of super cold propellant, but also flight computers and avionics that control the first eight minutes of flight. The Green Run test series will help validate that the SLS core stage is ready for its first flight on Artemis I and subsequent missions.

Check back at this blog for an update on core stage power up for the second Green Run hot fire. For more information about SLS Green Run, visit https://www.nasa.gov/artemisprogram/greenrun

Green Run Update: Engineers Repair Valve for Mid-March Hot Fire Test

Engineers have successfully repaired a liquid oxygen valve on the Space Launch System rocket’s core stage with subsequent checks confirming the valve to be operating properly. The team plans to power up the core stage for remaining functional checks later this week before moving forward with final preparations for a hot fire test in mid-March at NASA’s Stennis Space Center near Bay St. Louis, Mississippi. NASA anticipates setting a target date for the hot fire next week.

Propellant barges docked near the B-2 Test Stand Last week during checkouts for the second hot fire test, data indicated the valve (a type of valve called a pre-valve) was not working properly. The valve is part of the core stage’s main propulsion system and is opened at the beginning of the test and closed if necessary to stop the flow of liquid oxygen from the core stage propellant tank to the respective RS-25 engine during the hot fire.

While the valve was repaired over the weekend, the team continued to prepare the core stage, its four RS-25 engines, and the B-2 test stand for the second hot fire at Stennis. This hot fire test will be the last test before the Artemis I core stage is shipped to the agency’s Kennedy Space Center for assembly and integration with the rest of the rocket’s major elements and the Orion spacecraft.

Please check back at this blog for an update on the date NASA is targeting for the second Green Run hot fire. For more information about SLS Green Run, visit https://www.nasa.gov/artemisprogram/greenrun

Green Run Update: NASA Inspecting Valve, Continuing Hot Fire Preparations

NASA and Space Launch System (SLS) core stage prime contractor Boeing are thoroughly examining a liquid oxygen valve inside the stage’s engine section in order to identify repairs needed before a second hot fire with the Artemis I stage.

During preparations for the second hot fire, data indicated the valve was not opening correctly. Technicians installed platforms that allow engineers to access the valve inside the core stage engine section while the stage remains in the B-2 stand at NASA’s Stennis Space Center near Bay St. Louis, Mississippi. After completion of troubleshooting, which will continue over the weekend, NASA will be in a better position to identify a potential date for the second hot fire test.

In preparation for a second hot fire test, engineers are examining issues with a liquid oxygen valve inside the Space Launch System rocket’s core stage installed in the B-2 test stand at NASA’s Stennis Space Center near Bay St. Louis, Mississippi.

This valve, called a pre-valve, must be fully operational during hot fire testing. The valve is part of the core stage main propulsion system, and it helps deliver liquid oxygen propellant flowing from the liquid oxygen tank to an RS-25 engine. For the first hot fire on Jan. 16, all four liquid oxygen pre-valves performed as expected as did all four liquid hydrogen pre-valves.

The Green Run is a comprehensive series of tests for the SLS core stage before it launches the Artemis missions to the Moon, and the hot fire is the final and most intensive test. The Green Run tests have provided invaluable information on how the new rocket stage operates before it is used to launch the Artemis I mission.

Check back at this blog for an update on actions needed to resolve the issue, as well as the schedule for the hot fire test. For more information about SLS Green Run, visit https://www.nasa.gov/artemisprogram/greenrun