Tag: Core stage

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.

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.

Green Run Update: Hot Fire Met Many Objectives, Test Assessment Underway

For the Green Run hot fire test on Jan. 16, NASA set out to acquire test data to support 23 detailed verification objectives. To satisfy the objectives, hot fire test data is used in combination with analysis and testing that has already been completed. These detailed verification objectives are used to certify the design of the Space Launch System rocket’s core stage.

The preliminary assessment indicates that the data acquired met the goals for a number of the 23 objectives, such as those related to activities prior to engine ignition. The initial assessment also indicates that data acquired partially met the goals for several additional of the 23 objectives related to simultaneous operations of four RS-25 engines.

NASA and its industry partners, Boeing and Aerojet Rocketdyne, are continuing to assess the extensive data from the test. As part of the planned near-term activities, they will complete the final assessment determining which objectives were fully met and which ones were partially met. They also are evaluating the value of acquiring additional test data and a longer run time to augment the existing analyses and data.

Currently, the SLS core stage can still be loaded with propellant and pressurized 20 more times for a total of 22 cycles. Rocket stages like the core stage are designed to be loaded with cryogenic propellant and pressurized a specific number of times. These are called cryogenic loading cycles. Before Green Run testing began, SLS had allocated nine cryogenic cycles for testing at NASA’s Stennis Space Center in Bay St. Louis, Mississippi and has used two of those during the hot fire and wet dress rehearsal, with seven cryogenic cycles remaining for additional testing. For the Artemis I Iaunch, NASA is preserving 13 of the remaining 20 cryogenic loading cycles. These can be used for multiple launch attempts, a wet dress rehearsal on the launch pad, and other activities that require propellant loading and tank pressurization.

One of the critical activities that must happen before either another hot fire test or launch is drying and refurbishment of the engines. That activity is underway. NASA is continuing to inspect the core stage and its RS-25 engines on the B-2 test stand, and initial inspections indicate the hardware is in excellent condition.

Hardware inspection and data assessment will continue and will inform NASA’s decision on whether to conduct a second Green Run test or proceed with shipping the core stage to Kennedy for integration with other SLS hardware in the Vehicle Assembly Building.

SLS core stage
This infographic explains more about the core stage and its massive liquid hydrogen and liquid oxygen tanks that hold more than 700,000 gallons of propellant.

For more updates, images and videos, check back at this blog or the Green Run web site: https://www.nasa.gov/artemisprogram/greenrun

NASA conducted a media briefing with several experts who support the Green Run team on Jan. 19, and a replay will be available for 30 days by dialing 888-566-0617.

Green Run Update: Engines Igniting as Hot Fire Gets Underway 

The hot fire is underway for the Space Launch System (SLS) rocket core stage at NASA’s Stennis Space Center near Bay St. Louis, Mississippi.

Engine ignition began at approximately six tenths of a second before T-0, beginning with Engine 1, then Engines 3, 4, and 2 ignited in sequence a few hundredths of a second apart. The test is expected to last about 8 minutes and will include three different power levels for the engines, as well as two 30-second engine gimballing, or pivoting, movements to simulate flight steering commands. Depending on the rate propellant is burned the time is estimated to range from 485 to 493 seconds to simulate launch.

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

Green Run Update: Hot Fire Test Targeted for within an Hour

The teams are now targeting a hot fire test for NASA’s Space Launch System (SLS) rocket core stage within an hour. The team has completed a successful pressurization demonstration and is evaluating the data to ensure they are ready to proceed.

Live coverage is underway on NASA Television and the agency’s website.

Teams began the countdown for the hot fire test earlier today. This is the eighth and final test in the Green Run testing series for the rocket’s core stage that will launch NASA’s Artemis I mission around the Moon. Learn more about Green Run, and check back at this blog for updates on the SLS core stage hot fire test.

Green Run Update: Test Team Gives “Go” To Proceed with Tanking

The test team conducted a pre-test briefing in the Test Control Center at the B test complex at NASA’s Stennis Space Center near Bay St. Louis, Mississippi, and gave a “go” to proceed with testing and to fill the propellant tanks.

Over the next several hours, the teams will monitor the systems and load more than 700,000 gallons of cryogenic, or supercooled, liquid oxygen and liquid hydrogen that will be fed to the four RS-25 engines.

The hot fire will last up to 8 minutes and is scheduled to take place during a two-hour window that begins at 5 p.m. EST. Live coverage will begin at 4:20 p.m. EST on NASA Television and the agency’s website.

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

SLS core stageThis infographic provides information on the core stage including its two large propellant tanks.