NASA and Boeing have taken a crucial step forward in prepping the Space Launch System (SLS) rocket for Artemis III—the mission slated to return astronauts to the Moon—by completing thermal insulation on the core stage’s massive liquid hydrogen tank at the Michoud Assembly Facility in New Orleans.

“There are better process controls in place than we’ve ever had before, and there are specialized production technicians who must have certifications to operate the system. It’s quite an accomplishment and a lot of pride in knowing that we’ve completed this step of the build process,” said Boeing’s Brian Jeansonne, the integrated product team senior leader for the thermal protection system at NASA Michoud.

The operation involved applying a specialized thermal protection system (TPS) to shield the tank from extreme temperatures. It’s essential work: the tank must keep liquid hydrogen chilled at minus 423°F and endure the searing heat of launch and ascent. Using a robotic system, NASA and Boeing crews sprayed on 107 feet of foam insulation in just under two hours—marking the largest such application in spaceflight history.

“The thermal protection system protects the SLS rocket from the heat of launch while also keeping the thousands of gallons of liquid propellant within the core stage’s tanks cold enough,” said Jay Bourgeois, thermal protection systems lead at NASA Michoud. “Without it, the propellant would boil off too quickly to sustain a successful launch.”

Artemis III builds on the upcoming Artemis II crewed test flight and will introduce new systems, including next-gen spacesuits and a lunar lander, as NASA targets a historic first—sending astronauts to explore the Moon’s South Pole. The mission is seen as a stepping stone to human exploration of Mars.

Despite this progress, the future of the SLS program beyond Artemis III is murky. The rocket has faced repeated delays and ballooning costs—currently topping $2 billion per launch. As NASA pushes toward greater reliance on commercial launch systems like SpaceX’s Starship, some in the space policy community have questioned how long the SLS can remain viable.

Experts estimate there is a growing chance—around 30–50%—that Artemis III could be the SLS rocket’s final mission if commercial alternatives prove more reliable and cost-effective. Decisions about extending the SLS program may hinge on Artemis III’s performance and broader shifts in NASA’s strategy for deep space exploration.

For now, the agency is racing to meet Artemis III’s ambitious timeline, eyeing a late 2026 launch. Whether the SLS will be part of NASA’s long-term future—or a stepping stone soon left behind—remains to be seen.