Space Launch System Block 1

Ninety-eight metres tall on an 8.4 metre core, with 39,000 kilonewtons at liftoff from four RS-25 engines and two five-segment solid boosters. NASA publishes the trans-lunar figure, more than 27 tonnes, and does not publish a low orbit number at all; the 95 tonne figure carried here comes from elsewhere and should be read as a specification rather than a demonstrated result.

Almost none of it is new. The core engines are Space Shuttle main engines, built to be recovered and reflown, and every flight now drops four of them into the Atlantic. The boosters are stretched Shuttle solids. The tank diameter is the Shuttle external tank diameter. This was sold as risk reduction and it also happened to keep the Shuttle supply chain and its congressional districts intact, which is the more predictive explanation.

The cost is not an estimate from a critic. NASA's own Inspector General, in report IG-22-003, projected 4.1 billion dollars per launch through at least Artemis IV at roughly one mission a year, excluding all prior development spending. The SLS share of that is 2.2 billion, which buys two stages, two boosters, four engines and two adapters, every one of which is destroyed on the flight.

And then in April 2026 it worked. Artemis II launched on 1 April carrying Reid Wiseman, Victor Glover, Christina Koch and Jeremy Hansen, looped the far side of the Moon on a free-return trajectory, set a human distance record of 406,771 kilometres and splashed down on 11 April. It was the first crewed lunar mission since 1972, and nothing else in existence could have flown it.

The politics resolved the same way. A 2025 budget proposal to terminate SLS and Orion after Artemis III, citing a 140 percent overrun, was overridden by Congress, which put 4.1 billion behind Artemis IV and V with a mandated floor of 1.025 billion a year through 2029, then arranged for operations to pass to a Boeing and Northrop joint venture from Artemis V. It is the clearest political artefact in this section. It is also, now, a rocket that has carried people around the Moon.