NASA completed another step to prepare the SLS (Space Launch System) rocket for the Artemis III mission, when crew members of the agency’s Michoud assembly facility in New Orleans recently applied a thermal protection system in a core-level liquid hydrogen tank.
Building on the crew Artemis II flight test, the Artemis III will add new features to the human landing system and advanced space suits to send the first astronauts to explore the Lunar South Pole area and prepare humans to travel to Mars. Thermal protection systems are the cornerstone of successful space flight efforts to maintain human life and achieve spacecraft launches and controlled return.
This tank is the largest SLS flight hardware for Michoud insulation. The hardware requires extreme temperatures and rise to space during the launch process, so it requires thermal protection - and keeping the liquid hydrogen at 423 degrees Fahrenheit on the mat before launch.
"Thermal protection system protects the SLS rocket from the heat of the launch, while also keeping thousands of gallons of liquid propellant cold enough in the storage tanks on the core stage. Without protection, the propellant will boil before launch and cannot be replenished before launch," the thermal protection system, test and integration system at NASA Michoud. "Thermal protection systems are essential to protect all structural components of the SLS during launch and flight."
In February, SLS Core Stage Prime contractors, along with NASA and Boeing’s Michoud crew, completed a thermal protection system on the external structure of the rocket’s liquid hydrogen propellant tank, which used robotic tools in the largest single application in space flight history. The robot-controlled operation uses a spray foam insulating coating, dispensing 107 feet of foam to the storage tank in 102 minutes. When the foam is applied to the core stage, it makes the rocket's golden silk yellow. The sun's ultraviolet rays naturally "tanned" thermal protection, giving the SLS core stage an iconic orange color, such as the space shuttle's external water tank.
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While this may sound like a task similar to applying paint to a house or spraying insulation on an attic, it is a more complex process. Flexible polyurethane foams must withstand stringent application and testing conditions. In addition, there is a new challenge: horizontal spraying stage, something never done in large foam applications on Michoud's space shuttle external tanks. When sprayed with an automated process, most of all large shuttle tanks are in a vertical position.
Overall, the rocket's core phase is 212 feet and a diameter of 27.6 feet, the same diameter as the space shuttle's external water tank. Liquid hydrogen and liquid oxygen tanks supply four RS-25 engines for about 500 seconds before the SLS reaches low-Earth orbit, while the core stage is separated from the upper and NASA's Orion spacecraft.
“Even if spray is applied in just 102 minutes, there is a lot of careful preparation and planning before actually applying the foam,” said Brian Jeansonne of Boing, senior leader of the Thermal Protection System integrated product team at NASA Michoud. “There is better process control than ever before and there is a dedicated production technician that has to have certification to operate the system. It’s a very accomplishment and proud that they know we’ve completed this step of the build process.”
The core stage of SLS is built in the largest length and quantity ever built by NASA, and it is manufactured in Michoud using state-of-the-art manufacturing equipment. Michoud is a unique premium manufacturing plant in which the agency has built spacecraft components for decades, including the space shuttle's external tanks and the Apollo-programmed Saturn V rocket.
Through Artemis, NASA will send astronauts to explore the moon to gain scientific discoveries, economic benefits and lay the foundation for Mars' first crew mission.
For more information about Artemis activities, visit:
Jonathan Deal
Marshall Space Flight Center, Huntsville, Alabama.
256-544-0034
jonathan.e.deal@nasa.gov