The Competition of the Methalox engines

[meekGee]

Raptor is the best one, and it’s pretty simple why:

Should the Raptor ever meet the hoped for quality, aspirational reliability, dreamed of reusability, and claimed price, it's still doubtful that other engine users would find them appropriate for their needs.

Yeah, who wants any of these things?

Yup and as we've seen, having such requirements ends up slowing progress at the respective organizations even more..  Until at some point it won't be sustainable any more.  But it will drag on way longer than is slightly...

[DJPledger]

This thread is WAY off topic to be in the BO section. Please move it to the general discussion section.

[TrevorMonty]

This thread is WAY off topic to be in the BO section. Please move it to the general discussion section.

Should've been under SpaceX as eventually it was going turn into Raptor is best and ever other engines is useless thread.

Sent from my SM-G570Y using Tapatalk

[Robotbeat]

If Raptor gets to $1000/ton-of-thrust and a Thrust to Weight ratio of 200 (let’s be generous), that means the engine must cost only $200/kg. That’s extremely aggressive, but not impossible. An F-150 pickup truck costs $30,000 and has a mass of 2000kg, $15/kg. Ford Maverick comes down to around $10/kg.

[Robotbeat]

This thread is WAY off topic to be in the BO section. Please move it to the general discussion section.

Should've been under SpaceX as eventually it was going turn into Raptor is best and ever other engines is useless thread.

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The other engines aren’t useless because being reliant on a competitor is probably not a great idea (New Glenn vs Vulcan notwithstanding). Raptor is not a simple design. SpaceX has the most experience in making lots of rocket engines in the West, and a pretty aggressive development capability but it has taken them about a decade already to get to where they are now. So if you can’t use Raptor and want to develop and engine in-house, another, simpler engine cycle is not a bad approach at all. Gas generator is a good direction.

But we don’t need to pretend Raptor isn’t from a technical standpoint the better engine, and potentially the cheapest marginal cost as well. SpaceX invested a huge amount of money, time, energy, and people into Raptor, and it’s starting to pay off.

But time will tell how well different engines operate in real application.

[Robotbeat]

I don’t think pursuing such an advanced cycle was a mistake. It is a level of difficulty SpaceX can handle and therefore maybe appropriate.

But it’s possible Starship would’ve been further along if they had used a gas generator cycle like Merlin. The early Starship failures seem to have been related to Raptor failing (although often because it was given non-ideal conditions from the rest of the rocket). However, it would be a huge performance hit, and Starship might not have been feasible for their HLS bid.

[Davidthefat]

If RL keeps development in NZ, I feel like they will be the most disadvantaged in development of the next gen engine.

In the US, there are a lot of ex SpaceX and Rocketdyne, Blue Origin, etc. employees that they can’t be tapping into due to ITAR.


Edit: not just talent, but also vendors

[Robotbeat]

They do a lot of development in California.

[Kiwi53]

If RL keeps development in NZ, I feel like they will be the most disadvantaged in development of the next gen engine.

In the US, there are a lot of ex SpaceX and Rocketdyne, Blue Origin, etc. employees that they can’t be tapping into due to ITAR.

Edit: not just talent, but also vendors

ITAR compliance is not a NZ problem. NZ is a "5-Eyes" (AUS CAN NZ UK US) security partner and getting a facility and its staff ITAR cleared is not much more difficult in NZ than in the US. The RL facilities in Auckland and on the Mahia Peninsular must already be ITAR-cleared, otherwise they wouldn't be launching USAF and other US government satellites.

I'm sure that working for RL in NZ would be a very attractive proposition for "a lot of ex SpaceX and Rocketdyne, Blue Origin, etc. employees", if only for lifestyle reasons.

Yes, there is a smaller pool of potential on-shore vendors in NZ than in the USA.
On the other hand, RL have been pretty aggressive in buying their way into vertical integration in the last year or so.

[ZachF]

I don’t think pursuing such an advanced cycle was a mistake. It is a level of difficulty SpaceX can handle and therefore maybe appropriate.

But it’s possible Starship would’ve been further along if they had used a gas generator cycle like Merlin. The early Starship failures seem to have been related to Raptor failing (although often because it was given non-ideal conditions from the rest of the rocket). However, it would be a huge performance hit, and Starship might not have been feasible for their HLS bid.

Not pursuing a staged combustion engine would have massively effected the BEO performance of starship. Like 2-3x more required tanker flights on top of a much larger size.

[ZachF]

This thread is WAY off topic to be in the BO section. Please move it to the general discussion section.

Should've been under SpaceX as eventually it was going turn into Raptor is best and ever other engines is useless thread.

Sent from my SM-G570Y using Tapatalk

 
Just because Raptor is better it doesn’t mean the other engines are useless. You have to start somewhere.

A 300-bar staged combustion engine was simply not an option for RL or BO at their level of engineering and manufacturing expertise or timelines. It was for SpaceX, and maybe it will be for them too in the future.

This thread should probably be moved though.

[meekGee]

I don’t think pursuing such an advanced cycle was a mistake. It is a level of difficulty SpaceX can handle and therefore maybe appropriate.

But it’s possible Starship would’ve been further along if they had used a gas generator cycle like Merlin. The early Starship failures seem to have been related to Raptor failing (although often because it was given non-ideal conditions from the rest of the rocket). However, it would be a huge performance hit, and Starship might not have been feasible for their HLS bid.

Not pursuing a staged combustion engine would have massively effected the BEO performance of starship. Like 2-3x more required tanker flights on top of a much larger size.

"make it as simple as possible but not simpler than that", to paraphrase.

Yes, they needed the ISP, and the (related) power density - and it was within their abilities.

BO already chewed off more than they could digest.

[Robotbeat]

I don’t think pursuing such an advanced cycle was a mistake. It is a level of difficulty SpaceX can handle and therefore maybe appropriate.

But it’s possible Starship would’ve been further along if they had used a gas generator cycle like Merlin. The early Starship failures seem to have been related to Raptor failing (although often because it was given non-ideal conditions from the rest of the rocket). However, it would be a huge performance hit, and Starship might not have been feasible for their HLS bid.

Not pursuing a staged combustion engine would have massively effected the BEO performance of starship. Like 2-3x more required tanker flights on top of a much larger size.

Yup. The normal thing would’ve been to pursue hydrogen for that, tho. Methane is probably less of a headache, so methalox staged combustion it was.

But if you were just doing LEO, it would be fine.

Another option would be a smaller starship and more staging. Starship as-is is pretty heavy. Could be made a third the size and do Artemis just fine.

[JCRM]

If it was a war, then some of the battles to be won would be:

* first non-destructive firing
* first full duration firing
* first flight
* first orbital launch
* first commercial orbital launch
* first reuse on orbital launch
* first reuse on commercial launch
* first reuse within 4 weeks
* first reuse within 2 weeks
* first reuse in 48 hours
.
.
.
* profit?

some battles I hope are never lost:

* first chapter 11
* first loss of payload
* first loss of life

[DreamyPickle]

But it’s possible Starship would’ve been further along if they had used a gas generator cycle like Merlin. The early Starship failures seem to have been related to Raptor failing (although often because it was given non-ideal conditions from the rest of the rocket).

This argument is very unconvincing. Just how much further ahead would the Starship program be without any Raptor failures?

Even if they lost several prototypes along the way it seems that they're much faster at building the vehicles than they need. They retired several unflown prototypes because there was nothing worth proving after SN15, this can be seen as a buffer against Raptor failures that was unnecessary.

Right now they are waiting on FAA approval for the next test and there is no good indication that this was impacted by prior Raptor failures.

[Robotbeat]

But it’s possible Starship would’ve been further along if they had used a gas generator cycle like Merlin. The early Starship failures seem to have been related to Raptor failing (although often because it was given non-ideal conditions from the rest of the rocket).

This argument is very unconvincing. Just how much further ahead would the Starship program be without any Raptor failures?

Even if they lost several prototypes along the way it seems that they're much faster at building the vehicles than they need. They retired several unflown prototypes because there was nothing worth proving after SN15, this can be seen as a buffer against Raptor failures that was unnecessary.

Right now they are waiting on FAA approval for the next test and there is no good indication that this was impacted by prior Raptor failures.

Please don’t edit out the context.

[JCRM]

Please don’t edit out the context.

What important context do you feel was lost? That you didn't think it was a mistake? The argument you advanced stands alone of your views on the decision, and the response addressed that argument.

[Robotbeat]

I tend to take both sides of an argument before arriving at my conclusion. I’m granting a small possibility to Beck’s argument before concluding that Raptor was ultimately the right decision, for the reasons you suggest and more.

[trimeta]

I tend to take both sides of an argument before arriving at my conclusion. I’m granting a small possibility to Beck’s argument before concluding that Raptor was ultimately the right decision, for the reasons you suggest and more.

That's the difference between being the leader vs. the fast follower. If you're the leader and far enough ahead, you can probably take the time to do the job right (e.g., build the more complex engine that will ultimately make your vehicle better). If you're the fast follower, you need to actually be fast, otherwise you're going to fall further behind (see: Blue Origin).

This does theoretically risk the leader falling behind the fast follower, but in this case SpaceX's lead is so great there's absolutely no chance of that.

[ZachF]

I tend to take both sides of an argument before arriving at my conclusion. I’m granting a small possibility to Beck’s argument before concluding that Raptor was ultimately the right decision, for the reasons you suggest and more.

While I think Raptor is by far the best of these engines, I also think that Archimedes’ configuration (barest of bare bones GG) was also the best choice for rocket lab at this time. Rocket Lab would go bankrupt long before they could bring a 300bar FFSC engine to life at their current level of manufacturing and engineering knowledge base. Optimizing for shortest development time is 100% the best choice at their level of experience. They also have a solid upgrade tree in the future with fuel densification and staged combustion. (And hopefully full reuse)

Blue on the other hand almost seems like they got an inverted Pareto principle on the BE-4… An ORSC engine with only 134 bar (only about 20% higher than Merlin FT) of chamber pressure is like 80% of the engineering hassle of Raptor with 20% of the benefits…