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Comment by somenameforme | Hacker News Reader

This isn't for the rocket, just the structure that it's connected to before launch. Tens of billions of dollars have already been wasted on the rocket. I say "wasted" because it's already essentially obsoleted by the Falcon Heavy which has been ready to go for years, is reliable, and launches at a tiny fraction of the cost. And by the time Starship comes into play you're talking about a Ford Pinto being sold at Lambo Veneno Roadster prices.

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Just to add on, if you don't mind: the SLS uses four RS-25 engines, the exact same engines that were used on the Space Shuttle (admittedly, there is a plan to improve them later), as well as solid rocket engines that are derived from the Shuttle SRBs.

I actually do think that more than one US-based provider of space launch systems is something important, but it's wild to me that mature US launch systems can basically be cleanly divided into "companies trying to sell the same technology to the government for the fifth time over fifty years" and "SpaceX."

At this point would it have been cheaper to make Shuttle 2.0 with all the various flaws fixed lol

I'd like to expand on this and clarify for anyone reading this that it's not just using the same type of engines as the shuttle. They are literally the same reusable RS-25 engines taken off the shuttles over a decade ago and used for one final expendable launch. Likewise the SRB segments are reused from shuttle launches, but reconfigured and expended for one more launch on SLS. The $32 Billion spent so far on SLS have been to rearrange pieces from the shuttle parts bin.

There are further contracts to make new RS-25 engines and SRBs optimized for expendability once they run out of old shuttle equipment.

Falcon Heavy, fully expendable, can send about 15,190kg to TLI (Trans Lunar Injection). The Saturn V sent about 48,600kg to TLI.

The current SLS can send about 27,000kg to TLI, and block 2 is expected to send between 43,000kg and 47,000kg to TLI.

Could the Falcon Heavy be used on a multi-part moon mission? No doubt, but it's not in the same weight class as SLS.

The Falcon Heavy can ship can ship 16.8k kg to Mars [1] and that's at a higher delta V distance/cost than TLI. In general the SLS can carry around 50% more than a Falcon Heavy, but the Falcon Heavy (fully expended) costs 5-10% as much.

[1] - https://www.spacex.com/vehicles/falcon-heavy/

Thanks for the clarification. I dug around for numbers but didn't look in the most obvious place!

And yes, the cost difference is absolutely staggering.

I’m honestly shocked more “assemble in orbit” type mission structures haven’t been proposed. Falcon Heavy is just so convenient yet ignored.

> shocked more “assemble in orbit” type mission structures haven’t been proposed

It's unprecedented. A large part of Startship's technical risk in the Artemis programme is in-orbit refuelling.

That said, if IFT-5 or 6 can demonstrated recapture and an in-orbit fuelling attempt is made in 2025 that doesn't end catastrophically, I think the centre of mass of technical risk for Artemis shifts away from the novel fucking launch vehicle system that SpaceX has been tasked with building from the ground up to checks notes a rocket based on refurbished Space Shuttle engines and double checks this glorified launch tower.

Falcon Heavy has the thrust and the delta v, but it doesn’t have the fairing volume. Basically anything interesting that fits can be launched by smaller vehicles.

Starship will be a game changer in the most literal sense here as long as they figure out payload doors…

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