3 ms·

Historically, large quantity of engines has been considered problematic - it brings to mind the USSR N1 rocket and the difficulties with its 30 engines, which h

Historically, large quantity of engines has been considered problematic - it brings to mind the USSR N1 rocket and the difficulties with its 30 engines, which have been attributed as a (the?) reason for failure of the USSR Moon program.

ravedave5 5y ago
30 engines that fired for the first time at launch on a prototype vehicle. The falcon heavy launches with 27, with 0 failures so far.
- bmcahren 5y ago
  Falcon Heavy runs Merlin engines (Falcon heavy is three falcon 9's strapped together). Starship and Super Heavy booster are running Raptor methalox engines which by fuel choice alone has never been done before on an orbital rocket. The Raptor engines have failed to re-start during the landing sequence but I'm not sure we've seen enough of them to attest to any failure rate yet. The issue with restarting had to do with liquid methane sloshing in the nose cone.
  - rbanffy 5y ago
    > is three falcon 9's strapped together Now i just imagined the Ultraheavy, which should be 3 Superheavies strapped together.
nickik 5y ago
I tend to disagree with this. If you actually go threw the N1 and how it was developed, the conclusion to me is that it wasn't really the number of engines that was the main problem. The main issue they had is basically that the NK-17 engines were not tested before flight. Even worse, since they didn't have good computer back then, their 'what happens if an engine fails' sequence was very sub-optimal. I would suggest only one of the N-1 failures can reasonable be attributed to the choice in engine configuration. In one case their internal fuel channels were breaking because of vibration. All of these things seem much less likely to happen. The Booster has a computer and each engine has its own control. The Booster is much more capable of handing an engine shutdown or even an exploding engine. That has been demonstrated on the Falcon 9 a number of time. Each engine is individually tested before the flight and often they are then fired together on the ground, so there is much less fear of that. They have experience with 27 engines and the pipes required. Also, the Super Heavy used short Stainless steel tubes that should be fairly resilient. In general our engineering on how do this is just much better, better simulation, more experience, better knowledge oft the materials and the welding.

ravedave5 5y ago

30 engines that fired for the first time at launch on a prototype vehicle. The falcon heavy launches with 27, with 0 failures so far.

bmcahren 5y ago
Falcon Heavy runs Merlin engines (Falcon heavy is three falcon 9's strapped together). Starship and Super Heavy booster are running Raptor methalox engines which by fuel choice alone has never been done before on an orbital rocket. The Raptor engines have failed to re-start during the landing sequence but I'm not sure we've seen enough of them to attest to any failure rate yet. The issue with restarting had to do with liquid methane sloshing in the nose cone.
- rbanffy 5y ago
  > is three falcon 9's strapped together Now i just imagined the Ultraheavy, which should be 3 Superheavies strapped together.

nickik 5y ago

I tend to disagree with this. If you actually go threw the N1 and how it was developed, the conclusion to me is that it wasn't really the number of engines that was the main problem. The main issue they had is basically that the NK-17 engines were not tested before flight. Even worse, since they didn't have good computer back then, their 'what happens if an engine fails' sequence was very sub-optimal. I would suggest only one of the N-1 failures can reasonable be attributed to the choice in engine configuration. In one case their internal fuel channels were breaking because of vibration. All of these things seem much less likely to happen. The Booster has a computer and each engine has its own control. The Booster is much more capable of handing an engine shutdown or even an exploding engine. That has been demonstrated on the Falcon 9 a number of time. Each engine is individually tested before the flight and often they are then fired together on the ground, so there is much less fear of that. They have experience with 27 engines and the pipes required. Also, the Super Heavy used short Stainless steel tubes that should be fairly resilient. In general our engineering on how do this is just much better, better simulation, more experience, better knowledge oft the materials and the welding.