NASA is close to finalizing a plan to land humans on the Moon in 2024 and is expected to publicly discuss it next month. While the space agency has not released its revised strategy publicly, a recently updated "mission manifest" for the Space Launch System rocket may provide some clues about the new Artemis Program.

According to a planning document circulated at NASA's Marshall Space Flight Center this week, titled "Moon 2024 Mission Manifest," the space agency has set target launch dates for its first 10 Artemis Moon missions. In doing so, the agency has shaken up the order of launches and emphasized the use of NASA's Space Launch System in the lunar return.

The document confirms an earlier report that the first Artemis mission to test the SLS rocket will take place no earlier than April 2021. It also adds an additional Artemis mission in the run-up to the first human landing at the South Pole in late 2024:

April 2021 : Artemis I, Uncrewed test flight of Orion on Block 1 of SLS

: Artemis I, Uncrewed test flight of Orion on Block 1 of SLS January 2023 : Artemis II, Crewed flight of Orion around Moon on Block 1 of SLS

: Artemis II, Crewed flight of Orion around Moon on Block 1 of SLS August 2024 : Artemis III, Integrated lunar lander launched to Moon on Block 1B of SLS

: Artemis III, Integrated lunar lander launched to Moon on Block 1B of SLS October 2024 : Artemis IV, Crewed flight of Orion for human Moon landing on Block 1 of SLS

: Artemis IV, Crewed flight of Orion for human Moon landing on Block 1 of SLS September 2025 : Science mission, Launch of Europa Clipper on Block 1 of SLS

: Science mission, Launch of Europa Clipper on Block 1 of SLS June 2026 : Artemis V, Crewed flight of Orion to Moon on Block 1B of SLS

: Artemis V, Crewed flight of Orion to Moon on Block 1B of SLS June 2027 : Science mission, Launch of Europa Lander on Block 1B of SLS

: Science mission, Launch of Europa Lander on Block 1B of SLS August 2028 : Artemis VI, Crewed flight of Orion to Moon on Block 1B of SLS

: Artemis VI, Crewed flight of Orion to Moon on Block 1B of SLS February 2029 : Artemis VII, Cargo mission to Moon on Block 2 of SLS

: Artemis VII, Cargo mission to Moon on Block 2 of SLS August 2029 : Artemis VIII, Crewed mission of Orion on Block 2 of SLS

: Artemis VIII, Crewed mission of Orion on Block 2 of SLS February 2030 : Artemis IX, Cargo mission on Block 2 of SLS

: Artemis IX, Cargo mission on Block 2 of SLS August 2030: Artemis X, Crew mission on Block 2 of SLS

NASA said Thursday evening this mission manifest does not accurately reflect its Artemis plans.

"The proposed timeline in this article has many inaccuracies," said Matthew Rydin, press secretary for NASA. "We are currently in a blackout period because multiple companies have proposed human lunar lander solutions. These selections will be made in the coming weeks. However, the plan represented in this article is not the NASA plan."

But based upon the document obtained by Ars and recent internal briefings by NASA Associate Administrator Doug Loverro, it does seem increasingly clear that NASA is moving away from its original Artemis plan, which involved the use of multiple rockets and assembly of a Human Landing System in orbit around the Moon.

Loverro shakes things up

After arriving at NASA in late 2019 as the agency's new chief of human spaceflight, Loverro kicked off an assessment of the Artemis Program. As constituted at the time, NASA's plan called for using a mix of commercial rockets to pre-position components of a human lander near the Moon at the "Lunar Gateway." Four astronauts would then launch on the SLS rocket to rendezvous at the Gateway; two would descend to the surface of the Moon in the lander, and two would remain in orbit.

For this assessment, about 60 people at the agency and from industry sought to determine the status of the program as it was currently structured. After the analysis, Loverro told staffers at NASA he had "concerns" about whether the existing plan would work. In particular, during internal briefings, Loverro expressed doubts about the remote assembly of elements of the lunar lander at the Gateway. He also wanted NASA engineers to make sure the Orion spacecraft, with crew on board, could dock to the lander without the Gateway.

The potential revision of this plan, which may entail the launch of an entire lunar lander on an upgraded version of the SLS rocket, is notable for several reasons. Perhaps most significantly, it would place primary responsibility for NASA's Moon program on the shoulders of Boeing. That company is building the core stage of the SLS rocket, as well as an upgraded upper stage—the Exploration Upper Stage—that would now be required for use by August 2024 on the Block 1B version of the SLS. In fact, it would be required to accelerate development of the beefier SLS rocket.

"Due to the increases in number of flights and configurations, and the need for (Block 1B) one year earlier, much of the analysis work must be performed in parallel, rather than phased in series," the Marshall Space Flight Center document notes. Marshall, located in northern Alabama, oversees development of the SLS rocket.

Boeing on the critical path

In addition to this, such a plan would necessitate building an extra SLS core stage before fall 2024–four instead of three. This appears to be a change of heart by NASA Administrator Jim Bridenstine, who until now has said Boeing will have its hands full completing three core stages by that time.

A reliance on Boeing would come as the contractor is already struggling with both the SLS rocket and its Starliner spacecraft for NASA. Largely due to issues with the core stage, the SLS rocket will be delayed at least four years beyond its original launch date of December 2016, with billions of dollars in overruns. NASA's inspector general has characterized Boeing's execution on the SLS program as "poor." Moreover, Boeing's Starliner crew spacecraft had several significant software issues during its first flight in December 2019 and was unable to fly up to the International Space Station.

The new plan, if implemented, would substantially cut commercially developed rockets—such as SpaceX's Falcon Heavy and Blue Origin's New Glenn—back from the Artemis program. Previously, NASA had said it would launch elements of its Human Landing System on commercial rockets, because such vehicles cost much less than the estimated $2 billion rate per launch of the SLS vehicle. Now, perhaps, private rockets may be called upon to launch smaller pieces such as a lunar rover to the Moon's surface.

Lunar lander

The Marshall document does not specify the components of the Human Landing System that will be launched on the SLS rocket. NASA is still in a blackout period as it seeks to award preliminary contracts for the ascent, descent, and transfer modules of its Human Landing System. Those awards are likely to come sometime in mid-March.

There are four known bidders for lander development contracts: teams led by Boeing, Blue Origin, and Dynetics, as well as a plan from SpaceX. Of those, only Boeing has proposed building a fully integrated lander that would be launched on the Block 1B version of its SLS rocket. However, other bidders would presumably be allowed to propose integrated landers to be launched on the SLS booster.

The SLS launch manifest only tells part of the story of the Artemis Program. It does not specify the role a Lunar Gateway would play, although at the very least it does appear that the Gateway is pushed off into the future after a Moon landing. In that sense, this plan appears to be similar to that proposed by the US House of Representatives in its H.R. 5666 NASA authorization legislation.

Note: This article inadvertently stated that Artemis II would be uncrewed. It will be a crewed mission around the Moon, similar to Apollo 8. The error has been fixed.