NASA Prepares Next Artemis Rocket for Flight

Two months after the resounding success of Artemis II, NASA is again preparing for the next mission in its campaign to return humans to the Moon. The new Artemis paradigm aims to streamline production of the agency’s Space Launch System rocket and accelerate towards an annual mission cadence, and this begins in earnest with Artemis III. As NASA’s contractors work to meet the ambitious goals of the campaign, their work may give crucial staying power to the SLS program, whose future has been called into question since February.

The SLS rocket uses flight-proven solid rocket boosters and RS-25 main engines from existing Shuttle stock. Therefore, the rocket’s bespoke core stage is the main focus of SLS production for Artemis. Core stages are built at NASA’s Michoud Assembly Facility in New Orleans, LA, using facilities that once produced External Tanks for the Space Shuttle. Each core stage consists of two enormous fuel tanks, one for liquid hydrogen and the other for liquid oxygen, an engine section where the four RS-25 engines are installed, and additional structure to hold these components together and attach them to the upper stage.

Almost the entire rocket for Artemis III is already at Kennedy Space Center in Florida, with stacking set to begin this summer. The engine section arrived in the Vehicle Assembly Building last year, and the two aft booster segments were delivered by rail on April 13th. The core stage arrived in Florida aboard NASA’s Pegasus barge on April 27th, and was in the VAB the next day. The remaining eight booster segments arrived on June 8th. Only the unique “spacer” segment, which will replace the rocket’s upper stage for Artemis III, remains to be delivered. This one-off part is still being designed, though Artemis program manager Jeremy Parsons shared last week that some fabrication has already begun.

NASA is currently attaching the engine section to the other “four-fifths” of the core stage, and recently began moving the rocket’s four main engines into the VAB. Once the engines have been installed, the Artemis III core stage will be functionally complete and ready for stacking. NASA plans to begin stacking the solid rocket boosters this summer, and the rocket—minus the spacer and Orion—will roll to the pad for early testing by the end of the year.

Improving the Machine

Though SLS will fly a new configuration for Artemis III, the core stage retains lessons learned from its first two flights. During the launch of Artemis I, turbulent airflow at the points where the boosters attach to the core stage caused unplanned vibrations. Engineers chose to add small fins, called strakes, to the Artemis II rocket to better control this airflow. Terry Pricket, NASA’s SLS core stage chief engineer, told Space Scout the strakes worked as designed: “From all the data we’ve seen on Artemis II so far, they were highly successful in mitigating that vibration issue […] so we definitely intend on having those on Artemis III and going forward.”

Another issue from Artemis I will be resolved for the first time on the Artemis III core stage. During pad testing of the Artemis I rocket, engineers noted cracks in the foam insulation on its fuel tanks, and later observed some debris shedding during launch. “We had some foam debris problems from Artemis I […] that we were not able to mitigate in time for Artemis II, but those will be included on III,” said Prickett. Unlike the Space Shuttle with its exposed heat shield, shed foam poses little risk to the crew aboard Orion at the top of the rocket.

Despite the inclusion of the spacer for Artemis III, and the pivot to a Centaur V upper stage for future missions, few changes are needed throughout the rest of the rocket. “We haven’t seen anything in the [Artemis II] data so far that’s leading us to make any more changes than already planned,” Prickett explained. As for the “standardized” Block 1 variant, “we’ll just keep doing what we’ve been doing.”

Meanwhile, teams at Michoud are focused on streamlining core stage production to support NASA’s goal of an annual mission cadence. During the rollout of the Artemis III core stage from Michoud, NASA Associate Administrator Amit Kshatriya explained that the supply chain, not the facility itself, limits SLS production: “What we struggle most with is, around the country, getting the high quality parts we need […] That’s, right now, our biggest challenge: getting material into the factory, not making the factory go faster.” Indeed, each new core stage has already been built quicker than the last, and the rocket for Artemis III was the fastest build to date.

Gregg Eldridge, SLS resident office manager at Michoud, told Space Scout that the facility is studying options to combat supply chain bottlenecks. “To deal with late parts, we sometimes have to modify manufacturing sequences,” he said. “We’re always looking at shifting things around to be able to accept a part that may not come in as we originally hoped.” In an extreme case, a core stage could be shipped to Florida while waiting for certain parts, which could then be installed during stacking. On reaching an annual cadence, “it will be a challenge, but the administration has set that goal,” Eldridge said. “I think it’s doable.”

These improvements to the SLS program’s maturity and efficiency are being made at the same time that NASA leadership is attempting to cut its future short. Administrator Jared Isaacman has initiated plans to replace SLS with commercial alternatives for future Artemis missions, but other options are still unlikely to be available soon. SpaceX has increasingly shifted its focus to AI and orbital datacenters at the expense of Moon or Mars plans, and the recent explosion of Blue Origin’s New Glenn underscores the difference in maturity between these commercial options and NASA’s own, currently operational Moon rocket. Isaacman has even suggested to Congress that a commercialized SLS would likely be a strong candidate to replace itself.

For all of its past delays, the Space Launch System now has an established, accelerating production pipeline, which begs the question whether NASA would benefit in any way from eliminating it. NASA is still investing time, effort, and taxpayer dollars into making SLS an efficient, reliable, and sustainable launch vehicle; as Kshatriya explained to press, “increasing the pace of manufacturing [at Michoud] actually increases reliability.” Ending the program before these investments have a chance to pay off would seem needlessly wasteful; only time will tell whether NASA chooses to make the most of its proven Artemis rocket.