NASA: two options for the SLS upper stage and a lighter “Sortie” suit for the 2028 Moon landing

For the Artemis IV mission in 2028, NASA is considering two alternative upper stages for the SLS rocket. In a briefing published on Wednesday, November 4 on accelerating the Artemis programme, the agency also describes a second, lighter spacesuit for the first lunar walks. The plans were presented on Friday, October 23 by NASA Administrator Jared Isaacman and other officials, with the aim of returning Americans to the Moon in 2028.

Isaacman stressed that the programme must move quickly because the US’s “strategic competitors” are seeking a permanent presence beyond Earth. “We are absolutely focused on the mission, so we get world-changing results with the greatest possible speed, safety, economy and success,” he said.

Artemis III and IV

In practice, Artemis III, in 2027, will be a test in Earth orbit with four astronauts in Orion, launched on the SLS (Space Launch System), on a 14-day mission. Orion’s rendezvous, docking and handling with test versions of the landers, the craft that take astronauts from lunar orbit to the surface, will be tested. First the test Blue Moon from Blue Origin goes up, followed by Orion, which docks with it. Then a test Starship Version 3 from SpaceX is launched, Orion undocks from Blue Moon and docks with Starship. See our report on how the landers will be tested.

Artemis IV, in 2028, is the landing flight, launching from Kennedy Space Center in Florida. Starship will be refuelled in Earth orbit, meet Orion and carry it towards the Moon. Blue Origin will send Blue Moon Mark 2 to the Moon with transfer stages from Earth orbit, and the craft will meet Orion in a closer lunar orbit before descending to the surface. Both companies simplified their plans and are aiming for a crewed landing in 2028.

Two options for the upper stage

The first announcement concerns the SLS upper stage, the section that gives Orion its final push towards the Moon. NASA is considering two options: the current interim cryogenic propulsion stage, which uses liquefied propellants at very low temperature, and a stretched version of United Launch Alliance’s Centaur V, which carries more propellant. Studying both in parallel, the agency explains, ensures flexibility and avoids dependence on a single solution.

A lighter “Sortie” suit

The second announcement concerns spacesuits. Working with Axiom Space, which supplies the suits, NASA will develop a lighter suit called “Sortie” for the first lunar walks. It will weigh about half as much as the larger suit and let the agency proceed faster with the first surface missions. It does not replace Axiom’s main suit, which is intended for longer and more demanding missions in the future.

NASA also presented progress on hardware. Artemis III flight hardware is on schedule and its preparation times have been cut by about half. A critical fuel-line component was redesigned, built and tested in-house in five months, at about a tenth of the previous external supplier’s estimate. Jeremy Parsons, Artemis programme director, said NASA has some of the best technical knowledge in the world on rocket hardware and is rebuilding its core capabilities rather than outsourcing expertise.

Artemis astronauts will take on increasingly difficult missions at the Moon’s south pole, aiming at a permanent human presence on the Moon and preparing the first crewed mission to Mars. The full announcement, with graphics of the two missions, is in NASA’s release.