Artemis I Core Stage Arrives at Kennedy

The final piece of NASA’s Space Launch System (SLS) rocket that will send NASA’s Artemis I mission to the Moon has arrived at the agency’s Kennedy Space Center in Florida.

The SLS Program delivered the core stage rocket to the center’s Launch Complex 39 turn basin wharf after completing a successful series of Green Run tests at Stennis Space Center in Mississippi. The 212-foot-tall core stage, which is the largest rocket stage NASA has ever built, completed its voyage aboard the agency’s Pegasus barge on April 27. After a 900-mile journey, teams aboard the barge, which was modified to support SLS’s weight and length, safely piloted the specialized self-sustaining vessel to the spaceport.

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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.

This image shows the forward skirt that will be used on the core stage of NASA’s Space Launch System rocket for Artemis II, the first crewed mission of NASA’s Artemis program, at NASA’s Michoud Assembly Facility. The SLS core stage is made up of five unique elements: the forward skirt, liquid oxygen tank, intertank, liquid hydrogen tank, and the engine section. The forward skirt houses flight computers, cameras, and avionics systems. The hardware is located at the top of the 212-foot-tall core stage and connects the upper part of the rocket to the core stage. Soon, technicians will ready the forward skirt for the first of three core stage assembly mates called the forward join. The forward join consists of three main parts -- the forward skirt, liquid oxygen tank, and intertank – to create the top, or forward part, of the core stage. Together with its four RS-25 engines, the rocket’s massive 212-foot-tall core stage — the largest stage NASA has ever built — and its twin solid rocket boosters will produce 8.8 million pounds of thrust to send NASA’s Orion spacecraft, astronauts and supplies beyond Earth’s orbit to the Moon and, ultimately, Mars. Offering more payload mass, volume capability and energy to speed missions through space, the SLS rocket, along with NASA’s Gateway in lunar orbit, the human landing system, and Orion spacecraft, is part of NASA’s backbone for deep space exploration and the Artemis lunar program. No other rocket is capable of carrying astronauts in Orion around the Moon in a single mission. Image credit: NASA/Michael DeMocker

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.

This image highlights the liquid oxygen tank, which will be used on the core stage of NASA’ Space Launch System rocket for Artemis II, the first crewed mission of NASA’s Artemis program, at NASA’s Michoud Assembly Facility. The SLS core stage is made up of five unique elements: the forward skirt, liquid oxygen tank, intertank, liquid hydrogen tank, and the engine section. The forward skirt houses flight computers, cameras, and avionics systems. The liquid oxygen tank holds 196,000 gallons of liquid oxygen cooled to minus 297 degrees Fahrenheit. The LOX hardware sits between the core stage’s forward skirt and the intertank. Along with the liquid hydrogen tank, it will provide fuel to the four RS-25 engines at the bottom of the core stage to produce more than two million pounds of thrust to launch NASA’s Artemis missions to the Moon. Together with its four RS-25 engines, the rocket’s massive 212-foot-tall core stage — the largest stage NASA has ever built — and its twin solid rocket boosters will produce 8.8 million pounds of thrust to send NASA’s Orion spacecraft, astronauts and supplies beyond Earth’s orbit to the Moon and, ultimately, Mars. Offering more payload mass, volume capability and energy to speed missions through space, the SLS rocket, along with NASA’s Gateway in lunar orbit, the Human Landing System, and Orion spacecraft, is part of NASA’s backbone for deep space exploration and the Artemis lunar program. No other rocket can send astronauts in Orion around the Moon in a single mission. Image credit: NASA/Michael DeMocker

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.

NASA Removes Rocket Core Stage for Artemis Moon Mission from Stennis Test Stand

Crews at NASA’s Stennis Space Center near Bay St. Louis, Mississippi, worked April 19-20 to remove the first flight core stage of the agency’s Space Launch System rocket from the B-2 Test Stand in preparation for its transport to Kennedy Space Center in Florida. Operations required crews to lift the core stage from its vertical placement in the stand and lower it to a horizontal position on the B-2 Test Stand tarmac. The stage now will be loaded on NASA’s Pegasus barge for transport to Kennedy, where it will be prepared for launch of the Artemis I mission. Removal of the largest rocket stage ever built by NASA followed completion of a series of eight Green Run tests over the past year. During the Green Run series, teams performed a comprehensive test of the stand’s sophisticated and integrated systems. The series culminated in a hot fire of the stage’s four RS-25 engines on the B-2 stand March 18. During the hot fire, the four engines generated a combined 1.6 million pounds of thrust, just as during an actual launch. The test was the most powerful performed at Stennis in more than 40 years. NASA is building SLS, the world’s most powerful rocket, to return humans to deep space missions. As part of the backbone of NASA’s Artemis program, SLS will return humans, including the first woman and person of color, to the surface of the Moon to establish a sustainable presence and prepare for eventual missions to Mars.

Removal the first flight core stage of the agency’s Space Launch System rocket from the B-2 Test Stand
Credit: NASA
Removal the first flight core stage of the agency’s Space Launch System rocket from the B-2 Test Stand
Credit: NASA
Removal the first flight core stage of the agency’s Space Launch System rocket from the B-2 Test Stand
Credit: NASA
Removal the first flight core stage of the agency’s Space Launch System rocket from the B-2 Test Stand
Credit: NASA

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.

Orion Makes a Big Splash for Artemis II

The Orion spacecraft structural test article was successfully drop tested April 6 in the hyrdro impact basin at NASA’s Langley Research Center’s Landing and Impact Research Facility in Hampton, Virginia. Data collected from 500 sensors during the drop will help researchers finalize computer models of extreme landing conditions prior to Artemis II. This was the second of four drops in this series of tests.

 

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.

Space Launch System rocket’s intertank
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.

Ifographic on forward joinThe 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: Full Duration Hot Fire Successfully Completed on Mar. 18

Teams from NASA’s Space Launch System (SLS) Program conducted a successful full-duration 8 minute (499.6 seconds) hot fire of the Artemis I core stage on Thursday, Mar. 18 at NASA’s Stennis Space Center near Bay St. Louis, Mississippi on the historic B-2 Test Stand.

The hot fire got underway at around 4:40 p.m. EDT with all four RS-25 engines ignited successfully and produced 1.6 million pounds of thrust, as they will to launch the Artemis I mission to the Moon. During the test the engines consumed more than 700,000 gallons of liquid oxygen and liquid hydrogen propellant. The test was conducted with the core stage that will launch that first Artemis mission. Engineers collect data on how the stage behaved during critical operations, such as throttling the engines up and down and moving the engines dynamically in a variety of patterns. In coming days, engineers will scrutinize the data and determine if the stage is ready to be delivered to NASA’s Kennedy Space Center in Florida where it will be integrated with the twin solid rocket boosters already stacked in the Vehicle Assembly Building.

The core stage Green Run was a series of eight tests - all checked.
The core stage Green Run was a series of eight tests to checkout and validate operations with the largest rocket stage NASA has ever built. The flight hardware for the Artemis I mission was used for the test.

To learn more, tune in to NASA TV for a post-test briefing in about 2 hours.

Learn more about Green Run, and check back at this blog for updates on the SLS core stage hot fire test. Watch a replay of the test on NASA Television or NASA’s YouTube channel. For all the photos and videos related to the test, visit, the Green Run Album on NASA Images.org.

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 Proceeds With Plans for Second Hot Fire Test

NASA plans to conduct a second Green Run hot fire test as early as the fourth week in February with the Space Launch System (SLS) rocket’s core stage that will launch the Artemis I mission to the Moon. The Green Run is a comprehensive assessment of the rocket’s core stage prior to launching Artemis missions.

While the first hot fire test marked a major milestone for the program with the firing of all four RS-25 engines together for the first time for about a minute, it ended earlier than planned. After evaluating data from the first hot fire and the prior seven Green Run tests, NASA and core stage lead contractor Boeing determined that a second, longer hot fire test should be conducted and would pose minimal risk to the Artemis I core stage while providing valuable data to help certify the core stage for flight.

Inspections showed the core stage hardware, including its engines, and the B-2 test stand are in excellent condition after the first hot fire test, and no major repairs are needed to prepare for a second hot fire test at NASA’s Stennis Space Center in Bay St. Louis, Mississippi.

All SLS rockets use the same core stage design, so a second Green Run hot fire will reduce risk for not only Artemis I, but also for all future SLS missions. The Green Run series of tests is designed to certify the core stage design and verify that the new stage is ready for flight. The hot fire test is the final Green Run test and will provide valuable data that minimizes risk for American deep space exploration missions for years to come.

The Green Run team scrutinized data from the first hot fire test and determined that a second hot fire lasting approximately at least four minutes would provide significant data to help verify the core stage is ready for flight. A second hot fire test is planned for about eight minutes to simulate the amount of time it will take to send the rocket to space following launch. The Green Run wet dress rehearsal and first hot fire test completed several operations:

  • transitioning to the automated launch sequence operated by the core stage flight computer and Green Run software,
  • completing the terminal countdown sequence that is like the launch countdown
  • pressuring the tanks and delivering propellant to the engines and demonstrating performance of the core stage’s main propulsion system,
  • firing the engines at 109 percent power level, and
  • operating the thrust vector control system that steers the engines.

Conducting a second hot fire test will allow the team to repeat operations from the first hot fire test and obtain data on how the core stage and the engines perform over a longer period that simulates more activities during the rocket’s launch and ascent. To prepare for the second hot fire test, the team is continuing to analyze data from the first test, drying and refurbishing the engines, and making minor thermal protection system repairs. They are also updating conservative control logic parameters that resulted in the flight computer ending the first hot fire test earlier than planned. The team has already repaired the faulty electrical harness which resulted in a notification of a Major Component Failure on Engine 4. This instrumentation issue did not affect the engine’s performance and did not contribute to ending the first test early.

After the second hot fire test, it will take about a month to refurbish the core stage and its engines. Then, the Pegasus barge will transport the core stage to NASA’s Kennedy Space Center in Florida where it will be assembled with the other parts of the SLS rocket and the Orion spacecraft being prepared for the Artemis I launch later this year.