NASA’s revised plans to send astronauts back to the moon are quickly taking shape.
February 27, NASA Administrator Jared Isaacman revealed a new vision before The Artemis programand the missions the agency hopes will establish a long-term human presence on the lunar surface. The mix includes updated mission objectives for Artemis 3 and beyond, a shorter cadence between the launches of Space Launch System (SLS) rocket, and an SLS redesign that now comes into focus.
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At the time of the February 27 announcement, NASA did not indicate what the standardized SLS version would look like, or what its vision was for the SLS upper stage. But a simultaneous image release illustrating the new Artemis framework showed the program’s Orion crew capsule flying on a vehicle that was unmistakably neither the ICPS nor the EUS.
Instead, Orion and the service module were pictured burning under the power of what appears to be a Centaur V – the upper stage for United Launch Alliance’s (ULA) new Vulcan rocket.
This gave nourishment speculation at the timewhich was confirmed on March 6, when the government’s System for Award Management (SAM.gov) the site listed “Vulcan Centaur V Upper Stage for Space Launch System” contract option.
The possibility originates from NASA’s Marshall Space Flight Center in Alabama, and was described as a “sole source contract” for ULA to supply “next-generation upper stages for use in the Space Launch System (SLS) Artemis IV and Artemis V.”
“No other supplies or services will satisfy the agency’s requirements due to the highly specialized nature of this requirement,” agency officials added in the SAM.gov post.
Centaur V has a proven flight record on Vulcan, which debuted in 2024 and has four successful launches under its belt (with a few notable issuesnot related to Centaur). Its predecessors, the Centaurs III and IV, flew with the same RL10 engine and relied on much of the same technology built into the Centaur V to fulfill nearly 170 launches aboard ULA’s Delta IV and Atlas rockets.
Additionally, a Centaur-like variant, the Delta Cryogenic Second Stage, supported Orion on the spacecraft’s Exploration Flight Test-1 in December 2014, when a ULA Delta Heavy launched the capsule into the room for the first time. That mission sent an unmanned Orion to Earth orbit and back.
Centaur V is powered by two RL10 engines and is the largest and most advanced of the ULA Centaur line. It holds about twice as much fuel as the ICPS and is almost the same diameter as Orion and its service module.
“ULA’s Centaur (with minor modifications) is the only existing propulsion stage in space capable of meeting the SLS design parameters and upper stage performance characteristics while meeting NASA’s schedule,” NASA said in a submitted document justify awarding the contract to ULA without competition.
That schedule was also part of the shift in Artemis’ architecture. Artemis 2, which is on track for a possible launch attempt as early as April 1, remains unchanged. However, every mission after that has been reused and accelerated.
Artemis 2 will launch one crew of four astronauts on a 10-day mission to fly a single loop around the moon and back to Earth. Artemis 3 was originally designed as the program’s first lunar landing, targeted for 2028, but has been transformed into a test flight in 2027 with Orion and one or more Artemis lunar landers in low earth orbit. (Both SpaceX’s Starship and Blue origin‘s Blue moon landers were selected under Artemis’ Human Landing Services contract, and NASA has indicated that Artemis 3 will use either or both, depending on their readiness.)
Artemis 4 is now the first mission in the series with the goal of landing astronauts on the lunar surface, which NASA still hopes to achieve in 2028, with a follow-up landing on Artemis 5 potentially taking place the same year.
With Artemis 2 SLS stacked and nearly ready for launch, and Artemis 3 SLS already equipped to accommodate ICPS, Artemis 4 and 5 are the only two missions confirmed to launch Orion with the standardized SLS configuration and Centaur V upper stage, according to NASA’s contract specifications. which does not mention any missions beyond Artemis 5.
What will bring Orion to orbit past Artemis 5 can only be speculation at this point. SLS has experienced many delays and cost overruns during its long development, spurred criticism from many who see its continued funding as more of a jobs program driven by the US Senate than a sustainable space program. And some in the aerospace industry question the viability of SpaceX‘s Super Heavy booster — the first phase of Spaceship megarocket, which is still in development – to support Orion launches, or possibly even Starship enters as Artemis’ crew transport vehicle for Artemis 6 and beyond.
