NASA's Artemis II mission faced two consecutive delays in early 2026 due to technical issues with the Space Launch System (SLS) rocket, sparking renewed criticism of the program and calls to shift resources toward SpaceX's Starship.
The Artemis program aims to return humans to the Moon, with Artemis II set as the first crewed test flight, sending four astronauts on a lunar flyby. The mission, featuring NASA astronauts Reid Wiseman, Victor Glover, Christina Koch, and Canadian astronaut Jeremy Hansen, would mark the first human journey beyond low Earth orbit since 1972. Originally planned for late 2024, the launch had already been postponed multiple times due to issues like heat shield problems from the 2022 Artemis I flight and Orion spacecraft hardware fixes, shifting the target to early 2026. As preparations intensified at Kennedy Space Center, NASA conducted a wet dress rehearsal on February 3, 2026, simulating fueling and countdown procedures.
A technical glitch
However, a liquid hydrogen leak at the core stage interface disrupted the test, requiring pauses to adjust propellant flow and ultimately halting the countdown at T-5 minutes due to increased leak rates. Additional challenges included extended Orion closeout work, audio dropouts, and cold weather affecting cameras.
NASA Administrator Jared Isaacman announced the first delay in a post on X, stating, "With the conclusion of the wet dress rehearsal today, we are moving off the February launch window and targeting March for the earliest possible launch of Artemis II." He explained that such challenges were anticipated after more than three years since the last SLS launch, emphasizing, "These tests are designed to surface issues before flight and set up launch day with the highest probability of success." Isaacman added, "As always, safety remains our top priority, for our astronauts, our workforce, our systems, and the public." The issue mirrored hydrogen leaks from Artemis I preparations, prompting repairs and a second rehearsal. Engineers replaced seals on the Tail Service Mast Umbilical, and by mid-February, NASA advanced toward a March window "Since concluding a wet dress rehearsal Feb. 3 ahead of Artemis II, technicians have replaced two seals in an area where operators saw higher than allowable hydrogen gas concentrations during the test."
Yet another technical glitch
Progress was short-lived. On February 20, 2026, a separate problem emerged with helium flow to the SLS's Interim Cryogenic Propulsion Stage, the upper stage that propels Orion toward the Moon. Helium is used to pressurize tanks and purge lines, and the fault - possibly a clogged filter or valve - occurred after the rehearsal, necessitating a rollback to the Vehicle Assembly Building for diagnostics. NASA confirmed the second delay in another X post: "As soon as Tuesday, Feb. 24, we will roll our Moon rocket for our Artemis II mission off the launch pad, weather pending. Engineers are continuing to prepare for the move after encountering an issue with the flow of helium to the rocket’s upper stage." This pushed the launch to at least April 1, 2026, aligning with orbital mechanics. The consecutive setbacks - hydrogen leak followed by helium flow issue - extended delays by months, inflating costs for the SLS, which has already surpassed $23 billion in development and costs about $2 billion per flight.
The Space Launch System (SLS), NASA's flagship rocket for the Artemis program, has faced mounting criticism for its high costs, delays, and lack of reusability. Developed since 2011, the SLS draws on Space Shuttle-era technology, including RS-25 engines and solid rocket boosters, but at a staggering price - over $23 billion so far, with each launch estimated at $2-4 billion. Critics argue that this makes it unsustainable for long-term lunar exploration, especially when compared to commercial alternatives like SpaceX's Starship.
Before a new beginning
Calls to cancel the SLS have grown louder in recent years, particularly from space industry experts, private sector leaders, and fiscal watchdogs. Proponents of cancellation point to the rocket's slow development pace: After Artemis I's successful uncrewed test in 2022, subsequent missions like Artemis II have been plagued by technical issues, including hydrogen leaks and upper-stage problems, pushing timelines into 2026 and beyond. These setbacks highlight the SLS's complexity and low flight rate - potentially just one launch every few years - making it inefficient for building a sustained lunar presence.
In contrast, Starship offers a reusable design capable of rapid iteration and lower costs. SpaceX has conducted multiple test flights, demonstrating booster catches and suborbital capabilities, with ambitions for Mars missions. Advocates suggest NASA could pivot by contracting Starship for Artemis, leveraging its massive payload capacity (up to 150 tons to low Earth orbit) for landers, habitats, and crew transport. This shift could save billions, accelerate schedules, and foster innovation through public-private partnerships, similar to the Commercial Crew Program where SpaceX's Dragon has reliably ferried astronauts to the ISS.
The SLS is often labeled a "jobs program," distributing funds across congressional districts via contractors like Boeing and Lockheed Martin, rather than prioritizing efficiency. Budget proposals have even suggested phasing out SLS after a few flights to redirect resources to commercial systems.
“I know it is politically painful, but the right path is clear,” says a space expert and entrepreneur in a typical reaction. “Retire SLS, transition to SpaceX Starship. NASA can probably buy 2-3 Starships and operate them in house to preserve redundancy and workforce.”
This is a choice between legacy systems and bold, cost-effective innovation. Transitioning to Starship isn't without risks - its development has seen explosions and regulatory hurdles - but supporters believe it represents the future of spaceflight. By canceling SLS, NASA could focus on science and exploration, avoiding sunk costs and embracing a model that scales for Moon-to-Mars ambitions.
I don’t disagree. However, I don’t think this is the right moment to do so. “This is a time to support and celebrate NASA,” I posted. “After Artemis II and III, there'll be time to gradually switch from legacy technology to better technology.”
I made the same point in a November 2022 SpaceNews Op-ed, published after similar technical issues for the uncrewed Artemis I. “This is not the moment to criticize NASA. This is the moment to stand united behind NASA and support the Artemis program…,” I said. “I recommend patience to SpaceX and its enthusiastic supporters: if the Artemis program is successful, the time for Starship will come.”
I look forward to celebrating a successful Artemis II mission in April - perhaps not as a celebration of a new beginning, but as a celebration of the history of NASA, which has taken us back to the Moon, before a new beginning.