NASA Transition to Starship

SLS for now, Starship for keeps

Currently Starship appears on course to achieve its development goals i.e. lift 200 tonnes of payload to Low Earth Orbit (LEO), then refuel and send that payload to anywhere in the inner solar system. By comparison, the Block 1 version of Boeing’s Space Launch System (SLS) can launch 27 tonnes to the moon, hopefully rising to 35 tonnes for the future 1B version, which utilizes a more powerful Exploration Upper Stage (EUS). With regards to price, Starship should cost NASA ~$440m for a lunar mission, whereas SLS will cost $4.1bn, with this figure likely to exceed $5bn for Block 1B due to the higher cost EUS. Most strikingly, SLS might launch once every 2 years whereas Starship could fly every 24 hours due to full and rapid reusability. Hence, if Starship outperforms SLS in every metric, it seems inevitable NASA will eventually transition over to Starship, despite their longterm reliance on Boeing and political headwinds.

SpaceX is currently developing a new variant of Starship for NASA’s Artemis program, called the Starship Human Landing System (HLS), which will be used to shuttle astronauts between lunar orbit and the surface. Intriguingly the US Government Accountability Office recently reported that Starship couldn’t dock with the Lunar Gateway, a space station NASA planned to use as a waystation for lunar landings.

"Program officials estimate that the mass of the lunar lander Starship is approximately 18 times greater than the value NASA used to develop the [Gateway] PPE’s controllability parameters." ~ Ars Technica

Currently NASA intends to launch astronauts on SLS then have its Orion capsule dock directly with Starship HLS in lunar orbit, removing the need for the Gateway station. Unfortunately this only works as an interim measure to initiate moon landings. The Orion capsule is designed to carry 4 astronauts but NASA wants to build a sustained base on the moon and lunar economy, which will require hundreds of people plus thousands of tons of cargo... Fortunately SpaceX seem more than prepared for such an eventuality: -

"The thing I'm most excited about [with NASA's Artemis] is all of the surface elements, [since] Starship is fundamentally designed to transport very, very large amounts of cargo. [SpaceX is] excited to integrate things like habitats and rovers and supplies [with Starship to make a] rich ecosystem of technologies [for an] incredible Moon base. [Thinking about a Moon base analogous to Everest base camp,] staffed by hundreds or thousands of scientists and explorers." ~ SpaceX Director of Civil Space Development Nick Cumming/CST2022

Starship HLS could potentially carry 100 passengers at a time to the lunar surface, which suggests they’ll need a passenger Starship to ferry that number of people from Earth. Later on when propellant production is established on the moon they could dispense with HLS entirely, and fly a conventional Starship direct to the moon from Earth, then refuel it on the lunar surface ready for return.

Passenger Starship arrives at lunar base, credit SpaceX

NASA decision