When NASA Administrator Jared Isaacman announced improvements to the Artemis moon landing program, it was unclear whether the new mobile launcher built over the past two years at Kennedy Space Center would be used.
However, an outline of NASA’s reconfigured Artemis launch plans released Tuesday answers that question for the foreseeable future: no.
According to an update from the agency, “The agency no longer plans to use the Discovery Upper Stage or Mobile Launcher 2 because development of both has faced delays.”
The Space Launch System rocket used for the first three missions was in a so-called Block 1 configuration, with an upper stage called the Interim Cryogenic Propulsion Stage. The missions were assigned to use Mobile Launcher 1 (ML1), which was modified from the canceled Constellation program created by President George W. Bush in the early 2000s.
Artemis IV and V will use the Block 1B version of the SLS, including the higher exploration upper stage, which is designed to carry thousands of pounds of cargo to the moon.
The increase in height requires the new mobile launcher ML2.
Prime contractor Bechtel National Inc. added the final modular modules to the tower last summer, bringing its height to 377 feet. It has since been in final construction mode and is scheduled to be handed over to NASA in late 2026.
Bechtel did not respond when asked whether work on ML2 would stop immediately or be delivered to the agency as planned this year.
Its presence looms in the background as the Artemis II rocket aboard ML1 launches and returns from KSC’s 39-B launch pad, with the crane nearby and the team continuing to pursue an April launch opportunity.
ML1 was used on the Ares IX test mission of the Constellation program and then sat idle at KSC for many years before being used to support the first three Artemis missions.
However, ML2 may find potential uses in the future.
“ML2 is 90 percent complete. We can configure it as needed,” NASA Associate Administrator Amit Kshatriya said during a Friday news conference about the Artemis changes.
NASA does not plan to use ICPS as the upper stage for Artemis IV and V.
“NASA is evaluating alternatives for the rocket’s second stage,” the agency’s latest news said. “The interim cryogenic propulsion stage used for the first three missions will be replaced by a new second stage.”
The ML2 project was originally awarded a $383 million contract in 2019, with an original delivery date of 2023. An audit report released by NASA’s Office of Inspector General in August 2024 said costs had nearly tripled to more than $1 billion and delivery dates had been pushed back to late 2026.
The project is part of growing costs and delays in every aspect of the Artemis program. The OIG says that by the time Artemis III flies in 2023, the program will cost more than $93 billion (since it was originally announced in 2012). Those costs have now climbed to more than $100 billion.
President Donald Trump’s original 2025 NASA budget proposal, which was ignored by Congress, sought to end the use of SLS after Artemis III, and with it the need for ML2. After Sen. Ted Cruz took action to fund Artemis IV and V in Trump’s Big Beauty Act, it appears ML2 will be needed after all.
That was until Isaacman made the announcement last Friday.
Part of Isaacman’s criticism of SLS was the ballooning costs and delays of three years between launches.
He said the roadmap to move from Block 1 to Block 1B and the larger Block 2 version of SLS (which will also use ML2) is a failed roadmap.
“You will inevitably learn the same lessons over and over again,” he said, referring to the potential for new delays with each change in design. “So, standardize, increase production, put everything in there so you can increase your emissivity.”
The new plan aims to reverse the situation where SLS launches every 10 months.
Artemis 2 will make its first flight as soon as April 1, while Artemis 3, currently on a low-Earth orbit mission, will launch in mid-2027, and Artemis 4 and 5 are both scheduled to land on the moon in 2028.
The change in plans means other contractors such as Lockheed Martin and Boeing will need to refocus their efforts to achieve these goals.
“They understand what the requirements are. They know we need to bring in the hardware. That’s why we standardized the configuration,” Isaacman said. “You couldn’t do that if every rocket was a work of art.”
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