Elon Musk has suggested that NASA should move the workforce associated with the Space Launch System (SLS) to other sectors of the economy, arguing that the multibillion-dollar rocket faces significant cost questions.

In an X post on Tuesday, Musk wrote, “It would be better to repurpose the workforce to other parts of the economy,” in response to criticism regarding the program's costs. The comments come as renewed scrutiny focuses on the financial burden of the agency's Moon rocket.

According to a 2021 report by NASA’s Office of Inspector General (OIG), flying one SLS/Orion system through Artemis IV would average about $4.1 billion per launch. This figure includes the rocket, Orion spacecraft, European Service Module, and ground operations. The watchdog estimated that SLS production itself costs approximately $2.2 billion per mission.

The debate over the workforce stems from a 2012 Government Accountability Office (GAO) report. The GAO noted that the 2010 NASA Authorization Act directed the agency to leverage investments and workforce from the Space Shuttle and Constellation programs for SLS. The NASA OIG later stated this mandate led the agency to retain Shuttle-era systems, infrastructure, and contracts.

Boeing Co. (NYSE: BA) is the primary contractor for the SLS core stage, which the GAO identified as a cost-plus-award-fee contract. The agency has also faced criticism for underestimating the complexity of adapting heritage engines and boosters. Musk previously reacted to a NASA OIG estimate that the Artemis IV mobile launcher could cost $2.7 billion.

While Musk contrasted the SLS with SpaceX’s reusable Falcon Heavy—which can carry 63.8 metric tons to low Earth orbit—NASA lists the SLS Block 1 as capable of carrying 95 metric tons to low Earth orbit and more than 27 metric tons toward the Moon. The vehicles are not directly equivalent.

Policy is shifting, however. The Trump administration’s fiscal 2026 NASA budget proposal calls for an “orderly phase out” of SLS after Artemis III, with commercial transportation services taking over for later Artemis missions. Despite this, NASA is continuing its current operations; Artemis II carried astronauts around the Moon in April, and the agency is assembling the Artemis III vehicle for a 2027 crewed demonstration mission before a planned Artemis IV lunar landing in 2028.