The first (and uncrewed) lunar flight test mission of the Human Landing System (HLS), being developed by US space company SpaceX (whose founder and chief engineer is South African-born Elon Musk) for the US National Aeronautics and Space Administration’s (Nasa’s) Artemis crewed lunar exploration programme, may very well involve a craft that will not be identical to the production models that will carry astronauts. Indeed, it may be a “skeleton” of the crewed production variant of the HLS, US specialist space media have reported.

For the HLS, SpaceX is developing its ‘Starship’ spacecraft. This will be launched into space by the company’s own ‘Super Heavy’ rocket, also currently under development. To date, there have been five test flights (from the SpaceX test facility at Boca Chica in the US State of Texas) of Starships on their own (without their Super Heavy launch rockets). These took the spacecraft to altitudes of around 10 km, but four of them ended with the Starship engulfed in flames. The fifth, however, was a success. The Super Heavy itself has not yet flown. Musk, however, tweeted on Monday that launching a Starship into orbit was one of his two main targets for this year.

That the Starship’s first mission to the Moon might involve a “skeleton” craft was revealed at the recent Nasa Lunar Exploration Analysis Group, in a presentation by Nasa HLS programme manager Lisa Watson-Morgan. (It was she who used the word skeleton.) She also revealed that, for the HLS lunar demonstration flight, the Starship would have to land on the Moon, but it wouldn’t have to take off again.

“For the uncrewed demo, the goal is to have a safe landing,” she explained. “The uncrewed demo is not necessarily planned to be the same Starship that you see for the crewed demo. It’s going to be a skeleton because it just has to land. It does not have to lift back off, just for clarity. So clearly, we want it to, but the requirements are for it to land.”

(During Nasa’s previous crewed lunar exploration programme, Apollo, the Lunar Module made no uncrewed demonstration missions to or from the Moon. The first lunar landing by a Lunar Module – on the renowned Apollo 11 mission – was crewed, as was, consequently, its first take-off from the lunar surface.)

She stressed that the Starship (which SpaceX plans to use for a wide range of missions, not just as an HLS for Nasa’s Artemis programme) was still in the design and development stage. Changes were still being made to it. The Starship was not yet “ready to go”. Cooperation between Nasa and SpaceX was close and the company had so far been a “fantastic partner”.

During the uncrewed demonstration flight, the Starship will land in the Moon’s south polar region, which is where the Artemis III mission will touch down. The landing site for the demonstration mission has not yet been chosen. One important criterion is that the test landing site would not disrupt any of Artemis III’s possible landing places. The uncrewed demonstration flight is not expected before 2024, while the crewed Artemis III lunar landing mission is currently scheduled for late 2025.