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| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Exploration Ground Systems | 2/3 | https://en.wikipedia.org/wiki/Exploration_Ground_Systems | reference | science, encyclopedia | 2026-05-05T13:10:40.247548+00:00 | kb-cron |
In October 2017, NASA determined that modifying Mobile Launcher-1 (ML-1) to support the larger SLS Block 1B and Block 2 configurations would be impractical, as the required upgrades would introduce an estimated 33-month gap between launches. Instead, the agency elected to construct a second mobile launcher (ML-2) specifically designed for future SLS variants. Congress appropriated $350 million for the project in 2018, and in 2019 NASA awarded a $383 million, 44-month contract to Bechtel, with completion initially scheduled for March 2023. Construction of ML-2 began in July 2020. ML-2 was intended to support SLS Block 1B and Block 2 variant, both of which featured a taller configuration than Block 1 due to the Exploration Upper Stage (EUS). This required a higher crew access arm and redesigned umbilical connections to accommodate the different second stage. NASA anticipated fewer development challenges compared to ML-1, citing the incorporation of lessons learned. For example, following recommendations in a June 2019 Government Accountability Office report, NASA adopted integrated 3D modeling tools to improve design coordination, manage requirement changes, and enhance overall design maturity prior to construction. The total cost of ML-2 was originally estimated at under $500 million. However, the project experienced significant cost growth and schedule delays. By December 2023, NASA revised its estimate to approximately $1.5 billion—including $1.3 billion for the Bechtel contract—and delayed the expected delivery date to November 2026. In June 2024, NASA revised its estimate to approximately $1.8 billion, with a delivery date of September 2027, while maintaining expectations that Bechtel adhere to the December 2023 cost and schedule targets. A 2024 report by the NASA Office of Inspector General (IG) found that total costs could increase further, estimating that the project could reach approximately $2.7 billion by completion—more than three times the original projection. The report also concluded that ML-2 would likely not be ready to support a launch until at least 2029, after post-delivery preparations, exceeding the planned timeline for Artemis IV, the first mission scheduled to use SLS Block 1B. The IG attributed much of the cost growth and delays to contractor performance, noting that Bechtel had incurred significant overruns and underestimated the project’s scope and complexity, resulting in increased labor, equipment, and administrative costs. Ongoing technical challenges included steel fabrication and delivery issues and potential structural modifications that could increase the launcher’s weight and further drive up costs. By early 2026, more than $1 billion had been spent, and the launcher was estimated to be approximately 90 percent complete. In February 2026, NASA cancelled the SLS Block 1B and Block 2 variants, eliminating the primary need for ML-2 and rendering it surplus to the Artemis program. Amid continued delays and cost increases, NASA announced in March 2026 that it no longer planned to use ML-2. On March 29, 2026, the agency confirmed that a stop-work order had been issued to Bechtel, halting construction. Components common to ML-1 are to be removed from ML-2 for use as spares.
== Milestones ==