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Comment by jcun4128 | Hacker News Reader

> 31 raptor engines

That'll be something to see haha N1

The Falcon Heavy uses 27 engines and has a perfect track record ,so they've got some credibility here.

Yeah looks like 3 for 3 so far. It seems like a big number... as opposed to just 5 (Saturn V). What is the rationale for more smaller engines(other than offset/greater forces/new R&D)?

Losing one means less affect on the overall mission

i suppose 2 could blow up, no problem :)

Why only turn it up to 11 when you can turn it up to 31? See the Starship dial goes all the way to 31.

Things have different scaling laws. Very large rocket engines might not be practical for a range of reasons: wall thickness required to contain the high pressures (this is probably a big one) combined with the temperatures, combustion instability, controllability, and general ability to manufacture. Why are elephants and ants differently shaped? Another example is piston engines: large ones generally have lots of (relatively small compared to the overall displacement) cylinders rather than a couple of massive ones.

If a small number of rocket engines was required they would probably have a completely different design, perhaps an aerospike. Or maybe resurrecting Project Orion?

I never quite got the Orion(nuclear?) engine design eg. is it literal "nuclear explosions" or just using nuclear as a heat source.

I think they push fluid through the bells, maybe other materials(like ceramic) for the larger nozzles... can they use magnetic field to contain heat... probably not assumes it's ionized or something ha... heat still goes through magnetism. I got it, active heat destructive interface ha.

Literal nuclear explosions, Every few seconds, with a giant spring to even out the force.

Nuclear thermal rockets are much more interesting IMO because they were actually viable and in development until Nixon killed them for no good reason. They're coming back now though.

https://en.wikipedia.org/wiki/NERVA

https://spacenews.com/momentum-grows-for-nuclear-thermal-pro... (2019)

I take it you've literally never seen this? https://www.youtube.com/watch?v=KOO5S4vxi0o

The joke went entirely over your head boss.

Just to add clarification, Falcon Heavy uses the Merlin engine, not the Raptor engine.

Indeed, the N1 design [1] will finally be done right.

[1]: https://en.wikipedia.org/wiki/N1_(rocket)#Block_A_first_stag...

The Raptor engines are more advanced than those NK-31's right? I mean by newer manufacturing but I remember seeing something about these Russian engines that were closed off in some factory somewhere/later(years) found and they were supposedly still more advanced/powerful(efficient?) than modern rockets.

You likely meant his engine: https://en.wikipedia.org/wiki/RD-180

It wasn't used in the Soviet lunar program; these are remnants of the Soviet Space Shuttle-like program (specifically the Energia rocket that lifted the Buran space plane).

yeah that's possible those are the ones, I just remember seeing some documentary about finding these Russian rocket engines that were hidden away to protect them from being destroyed I think

edit: oh it's NK33/RD180 [0]

[0] https://www.youtube.com/watch?v=TMbl_ofF3AM

You are right and by some measures they were. However current engines like Raptor, BE-4 and in some ways Marlin, will be in many way more advanced.

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