Stas Bush wrote:As for superboosters, I would negotiate the UR-700
M with a 750 ton lift capacity versus the Sea Dragon before the FASTA.
Unlike Sea Dragon, the UR-700M is based on the tested technologies of the multibooster UR-500K Proton which had good reliability and serviced most of OMSK Space Agency and Space Forces launches. Everything from engines to booster shapes is reliable and more or less tested. The Sea Dragon is a single-booster giant vehicle with great potential for structural stress failure.
While some may find the 750 ton capacity "excessive", I would say that the production cycle of the UR-700M would be merely 50% longer than the UR-700 which had a projected 400-500 day cycle with 1960 technologies.
The extra-large lift capacity is important for lifting extra-large orbital habitats and possible orbital assembly complexes for space exploration missions. We have the right to change the shape of space exploration!

More boosters are in fact less reliable. The reliabilty factors of the individual engines multiply. Net result is that a reliability of 99% for an individual engine results in a total reliability of around 58% for the entire rocket. It's possible they have over engined the rocket to compensate. Then you also have the problem that a stage could fail to separate, which is also enormously more likely with 8 different staging points, compared to 1.
None of the engines in the UR-700M have flown. They use entirely different propellants from the Proton (LOX/Kerosene and LH2 versus UDMH and Tetrazine). The engines are complicated staged combustion design. The general shape of the rocket has flown, but most tandem rockets have that general shape.
The drivers behind the Sea Dragon are simplicity and robustness. It's primarily constructed out of 8mm thick high strength stainless steel. That's more akin to a submarine in construction than a rocket. The chance of a structural failure is nearly nil.
It utilizes a simple pressure fed engine (of enormous size). There's nearly no moving parts, increasing reliability. The only real moving parts are the throttling valves. The reduced number of engines enhance reliability, since the rocket either goes with the full engine burning, or it doesn't go at all.
It's sea launch and recovery simplify the launch site tremendously. No need to spend billions on a new launch pad. Just need a nuclear fueling ship, for the LOX and LH2 propellants, said ship mostly likely being a nuclear ISCA ship.
"preemptive killing of cops might not be such a bad idea from a personal saftey[sic] standpoint..." --Keevan Colton
"There's a word for bias you can't see: Yours." -- William Saletan