The Competition of the Methalox engines

[Tywin]

Which engines will be better in weight efficiency, ISP, reliability, power, etc....

In short, which will be the best Methalox engine in this decade?

JD-1

TQ-12

Raptor

BE-4

Aeon-R

Archimedes

Prometheus

Dhawan-1

RD-0169

[Tywin]

If we are lucky we will see 3 of these engines debut this year, the TQ-12, the Raptor, and the BE-4...

[Lemurion]

I don't know that this is a good question. Consider the BE-4, Raptor, and Archimedes. All three engines are designed to power reusable first stages, but they use different combustion cycles and have different ISPs. Each company has made different decisions due to their individual needs.

[DreamyPickle]

There is really not much of a point into a topic asking what is the "best" engine. These engines are being designed for different applications with different goals and don't particularly compete with each other.

There is a general industry trend where launch companies are developing their own engines which are not sold externally so comparing engines is getting less and less relevant. The success of engine development is entirely tied to their launcher.

[TrevorMonty]

As per others comments horses for courses.
Which is better a race car engine with excellent power to weight but short life or car engine which is lower powered, heavier but has more low down torque and is good for 200-400,000kms.

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[spacenut]

Ok, I'll bite, which is the best for booster engines, T/W ratio?

Then which is the best for upper stage engines, ISP? 

These are the two main choices I see.  I would think Raptor would have a better T/W ratio than BE-4 since BE-4 is a larger engine.  Don't know about the others.  Upper stages?  Don't know.  Anyone know more about this. 

[Yggdrasill]

T/W isn't very important for a booster engine, it's more important for an upper stage engine. The most important things for a booster engine would in my opinion be:

1. Price per kN
2. Reliability
3. Thrust to nozzle exit area. (Higher means you can make higher untapered rockets)
4. For reusable engines, little to no required refurbishment.

[Tywin]

T/W isn't very important for a booster engine, it's more important for an upper stage engine. The most important things for a booster engine would in my opinion be:

1. Price per kN
2. Reliability
3. Thrust to nozzle exit area. (Higher means you can make higher untapered rockets)
4. For reusable engines, little to no required refurbishment.

And what are your favorites in those categories?

[TrevorMonty]

T/W isn't very important for a booster engine, it's more important for an upper stage engine. The most important things for a booster engine would in my opinion be:

1. Price per kN
2. Reliability
3. Thrust to nozzle exit area. (Higher means you can make higher untapered rockets)
4. For reusable engines, little to no required refurbishment.

For a RLV booster engine life is more important than build cost . In case of expendable US low build cost is very important.

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[Yggdrasill]

T/W isn't very important for a booster engine, it's more important for an upper stage engine. The most important things for a booster engine would in my opinion be:

1. Price per kN
2. Reliability
3. Thrust to nozzle exit area. (Higher means you can make higher untapered rockets)
4. For reusable engines, little to no required refurbishment.

And what are your favorites in those categories?

I'm really liking Raptor across the board. I just think the volume SpaceX is planning will give extremely low cost per unit, while they at the same time get so much experience flying these engines which allows them to tweak away most of the minor flaws for reliability/reuse over the next couple of years. It's the engine that is furthest along in it's development and I don't see them losing ground.

For a RLV booster engine life is more important than build cost . In case of expendable US low build cost is very important.

I agree engine life is very important for the reusable engines. The number one metric could really be cost per kN per flight. In which case metric number 4 could really be eliminated.

[Yggdrasill]

For upper stage engines, the most important metrics in my book are:

1. Cost per kN per flight
2. Specific Impulse
3. Thrust to weight

I think Raptor comes out quite well on this too.

[Tywin]

For upper stage engines, the most important metrics in my book are:

1. Cost per kN per flight
2. Specific Impulse
3. Thrust to weight

I think Raptor comes out quite well on this too.

And what is your second choice for a first stage and second stage?

[Yggdrasill]

And what is your second choice for a first stage and second stage?

For the first stage I think I like the BE-4 the most for my second choice. For the second stage I'm thinking the Aeon-1 Vacuum.

Admittedly, I just don't know much about several of the options. And I prefer more mature designs. Getting to market quickly is important in getting the launch cadence up, and getting the launch cadence up is very important for cost and reliability.

[Lemurion]

After doing a bit more research, there really isn't a lot of information available on many of these engines. What there is seems to indicate that they have very little in common other than propellant choice. Some, such as the Aeon-R and Archimedes are very low TRL. Most of the engines that I could find information on are gas-generator, which is perfectly workable but hardly cutting edge. The only information I found on Dhawan 1 was that it was probably an expander cycle, while the JD-1 is pump-fed.

There is no war, and the only real competition at this point in my opinion is that between BE-4 and Raptor, and even that's more an artifact of circumstance. Both are staged combustion engines, of roughly similar performance, to be developed and used by companies competing for the same contracts, and set to enter service roughly simultaneously. The thing is, both engines would have been in a similar competition regardless of the propellant choice.

Archimedes may be in some competition with BE-4 in future as Neutron will theoretically have some competitive overlap with New Glenn, but even that's a bit too far out to bank on at this point.

[Tywin]

After doing a bit more research, there really isn't a lot of information available on many of these engines. What there is seems to indicate that they have very little in common other than propellant choice. Some, such as the Aeon-R and Archimedes are very low TRL. Most of the engines that I could find information on are gas-generator, which is perfectly workable but hardly cutting edge. The only information I found on Dhawan 1 was that it was probably an expander cycle, while the JD-1 is pump-fed.

There is no war, and the only real competition at this point in my opinion is that between BE-4 and Raptor, and even that's more an artifact of circumstance. Both are staged combustion engines, of roughly similar performance, to be developed and used by companies competing for the same contracts, and set to enter service roughly simultaneously. The thing is, both engines would have been in a similar competition regardless of the propellant choice.

Archimedes may be in some competition with BE-4 in future as Neutron will theoretically have some competitive overlap with New Glenn, but even that's a bit too far out to bank on at this point.

Which engine is better for you the Aeon-R or Archimedes?

[Lemurion]

After doing a bit more research, there really isn't a lot of information available on many of these engines. What there is seems to indicate that they have very little in common other than propellant choice. Some, such as the Aeon-R and Archimedes are very low TRL. Most of the engines that I could find information on are gas-generator, which is perfectly workable but hardly cutting edge. The only information I found on Dhawan 1 was that it was probably an expander cycle, while the JD-1 is pump-fed.

There is no war, and the only real competition at this point in my opinion is that between BE-4 and Raptor, and even that's more an artifact of circumstance. Both are staged combustion engines, of roughly similar performance, to be developed and used by companies competing for the same contracts, and set to enter service roughly simultaneously. The thing is, both engines would have been in a similar competition regardless of the propellant choice.

Archimedes may be in some competition with BE-4 in future as Neutron will theoretically have some competitive overlap with New Glenn, but even that's a bit too far out to bank on at this point.

Which engine is better for you the Aeon-R or Archimedes?

At this point I have no preference, and no reason to have one. It's too early to tell.

[Gliderflyer]

It's going to be hard to determine which engine is "best" as most engines are very custom and fitted to their specific roles. You aren't going to use a Raptor on a smallsat orbital tug, and you aren't going to use 2000 tiny RCS thrusters on a 100 ton lander. You will always be able to shift the "what is better" goalposts to make your favorite engine win, because most are already "winning" at their specific task.

That being said, I would cast my vote for the one I'm working on (which didn't make the list).

[Tywin]

It's going to be hard to determine which engine is "best" as most engines are very custom and fitted to their specific roles. You aren't going to use a Raptor on a smallsat orbital tug, and you aren't going to use 2000 tiny RCS thrusters on a 100 ton lander. You will always be able to shift the "what is better" goalposts to make your favorite engine win, because most are already "winning" at their specific task.

That being said, I would cast my vote for the one I'm working on (which didn't make the list).

Oh wow, can you say the name of the engine?

A new BE-5 or BE-6?

[Gliderflyer]

It's going to be hard to determine which engine is "best" as most engines are very custom and fitted to their specific roles. You aren't going to use a Raptor on a smallsat orbital tug, and you aren't going to use 2000 tiny RCS thrusters on a 100 ton lander. You will always be able to shift the "what is better" goalposts to make your favorite engine win, because most are already "winning" at their specific task.

That being said, I would cast my vote for the one I'm working on (which didn't make the list).

Oh wow, can you say the name of the engine?

A new BE-5 or BE-6?

ALPACA main engine.

[Tywin]

It's going to be hard to determine which engine is "best" as most engines are very custom and fitted to their specific roles. You aren't going to use a Raptor on a smallsat orbital tug, and you aren't going to use 2000 tiny RCS thrusters on a 100 ton lander. You will always be able to shift the "what is better" goalposts to make your favorite engine win, because most are already "winning" at their specific task.

That being said, I would cast my vote for the one I'm working on (which didn't make the list).

Oh wow, can you say the name of the engine?

A new BE-5 or BE-6?

ALPACA main engine.

Does the work continue in ALPACA?

[Gliderflyer]

Does the work continue in ALPACA?

Appendix N

[DanClemmensen]

Does the work continue in ALPACA?

Appendix N

To expand that a bit, NASA awarded five contracts on 14 Sep 2021 for design work on the "sustainable HLS" to be used after the two  landings of the "initial HLS" (i.e., Starship HLS). Dynetics got the biggest award ($40 million). SpaceX got the smallest ($10 million), presumably because that was all they asked for to improve on the initial Starship HLS. The other three awards were to Blue Origin, Lockheed Martin, and Northrup Grumman, presumably for a new version of their ILS: these three awards sum to about $95.6 million.

For an overview, see:
    https://en.wikipedia.org/wiki/Artemis_HLS_development_history
For the award announcement, See:
    https://www.nasa.gov/press-release/nasa-selects-five-us-companies-to-mature-artemis-lander-concepts

Personal opinion: the only way any lander other than the gen 2 Starship HLS would be used is if the Starship HLS program fails completely. I suppose the extra $135 million is basically an insurance policy. I could be wrong and the other teams may be doing something other than incremental improvement of their prior designs. The prior designs were reasonably close to meeting the initial HLS requirements, while Starship HLS massively exceeded them.

[Hug]

Oh wow, can you say the name of the engine?

A new BE-5 or BE-6?

ALPACA main engine.

Contextually humorous, the BE-5 was Blue's methalox lunar landing engine before it got dropped for the BE-7.

[Gliderflyer]

Oh wow, can you say the name of the engine?

A new BE-5 or BE-6?

ALPACA main engine.

Contextually humorous, the BE-5 was Blue's methalox lunar landing engine before it got dropped for the BE-7.

Interesting, I heard it was something else.

[trimeta]

Does the work continue in ALPACA?

Appendix N

To expand that a bit, NASA awarded five contracts on 14 Sep 2021 for design work on the "sustainable HLS" to be used after the two  landings of the "initial HLS" (i.e., Starship HLS). Dynetics got the biggest award ($40 million). SpaceX got the smallest ($10 million), presumably because that was all they asked for to improve on the initial Starship HLS. The other three awards were to Blue Origin, Lockheed Martin, and Northrup Grumman, presumably for a new version of their ILS: these three awards sum to about $95.6 million.

For an overview, see:
    https://en.wikipedia.org/wiki/Artemis_HLS_development_history
For the award announcement, See:
    https://www.nasa.gov/press-release/nasa-selects-five-us-companies-to-mature-artemis-lander-concepts

Personal opinion: the only way any lander other than the gen 2 Starship HLS would be used is if the Starship HLS program fails completely. I suppose the extra $135 million is basically an insurance policy. I could be wrong and the other teams may be doing something other than incremental improvement of their prior designs. The prior designs were reasonably close to meeting the initial HLS requirements, while Starship HLS massively exceeded them.

Veering off-topic here, but I thought the whole point of Appendix N was to facilitate proposals for LETS, and the ultimate goal is to select two providers for LETS. So although Starship will likely win one slot, there's another that could go to Dynetics or National Team. Assuming there's actually enough funding, but perhaps Congress will be sufficiently forewarned this time that if they want two winners, they need to allocate money for two winners.

[Yggdrasill]

Logically, it doesn't make too much sense with two providers for HLS. We are talking about 1-2 landings per year, at most.  That'a really low rate, which means expensive, and then you divide it by two? It's just economically irresponsible. And redundancy isn't really needed for safety or anything. If that was the motivation, you would want to look at a second provider for Orion-like capabilities. But that something is expensive and unnecessary is no huge obstacle for Congress, of course.

I think the point of allowing for multiple awards, and new entrants, is to ensure a competitive process where the best possible bids are provided. You wouldn't want everyone except SpaceX to drop out. But I would assess the actual chance of a second provider being selected to be relatively low. That's not to say SpaceX is certain to get selected - they need to be competitive. But they are of course quite well positioned to give the best bid.

[DanClemmensen]

Does the work continue in ALPACA?

Appendix N

To expand that a bit, NASA awarded five contracts on 14 Sep 2021 for design work on the "sustainable HLS" to be used after the two  landings of the "initial HLS" (i.e., Starship HLS). Dynetics got the biggest award ($40 million). SpaceX got the smallest ($10 million), presumably because that was all they asked for to improve on the initial Starship HLS. The other three awards were to Blue Origin, Lockheed Martin, and Northrup Grumman, presumably for a new version of their ILS: these three awards sum to about $95.6 million.

For an overview, see:
    https://en.wikipedia.org/wiki/Artemis_HLS_development_history
For the award announcement, See:
    https://www.nasa.gov/press-release/nasa-selects-five-us-companies-to-mature-artemis-lander-concepts

Personal opinion: the only way any lander other than the gen 2 Starship HLS would be used is if the Starship HLS program fails completely. I suppose the extra $135 million is basically an insurance policy. I could be wrong and the other teams may be doing something other than incremental improvement of their prior designs. The prior designs were reasonably close to meeting the initial HLS requirements, while Starship HLS massively exceeded them.

Veering off-topic here, but I thought the whole point of Appendix N was to facilitate proposals for LETS, and the ultimate goal is to select two providers for LETS. So although Starship will likely win one slot, there's another that could go to Dynetics or National Team. Assuming there's actually enough funding, but perhaps Congress will be sufficiently forewarned this time that if they want two winners, they need to allocate money for two winners.

"Congress" did not want two initial HLS winners, they wanted one winner: the national team. Then SpaceX came in at less than half the price and more than ten times the capability by any reasonable technical measure. "Congress" then tried a few tricks to fund the national team as a second provider, but the appropriation did not go through. (I have often wondered based on no information whatsoever why NASA extended the design phase by two months. Maybe to give the other teams a chance to re-evaluate based on rumors of Starship HLS?)  We will see what happens for the "sustainable" HLS. This would all be entirely off-topic except that apparently all of the HLS candidates use methalox engines somewhere in the mission.

[ZachF]

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

If RL had a Raptor-quality engine at the price SX is paying, they wouldn’t be using Archimedes.

If Blue had a Raptor-quality engine at the price SX is paying, they wouldn’t be using BE-4.

If Arianespace had a Raptor-quality engine at the price SX is paying, they wouldn’t be using Prometheus.

[libra]

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

If RL had a Raptor-quality engine at the price SX is paying, they wouldn’t be using Archimedes.

If Blue had a Raptor-quality engine at the price SX is paying, they wouldn’t be using BE-4.

If Arianespace had a Raptor-quality engine at the price SX is paying, they wouldn’t be using Prometheus.

And if my grandmother had wheels, we would call her a wagon (sorry, couldn't resist !)

[JCRM]

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.

[TrevorMonty]

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

If RL had a Raptor-quality engine at the price SX is paying, they wouldn’t be using Archimedes.

If Blue had a Raptor-quality engine at the price SX is paying, they wouldn’t be using BE-4.

If Arianespace had a Raptor-quality engine at the price SX is paying, they wouldn’t be using Prometheus.

Raptor is to big for Neutron. High performance doesn't mean low operating costs or long life both of which make for low cost RLV.


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[Yggdrasill]

Raptor is to big for Neutron. High performance doesn't mean low operating costs or long life both of which make for low cost RLV.

3x Raptor would be fine. (Coincidentally that's also the number of Raptors SpaceX has most experience flying.) But of course, the further along the design process goes with 7 engines, the less attractive it would be to change the number of engines. They might not want to make the change if the Raptors became available today, but if they were available right at the start of the design process, they would obviously have been very desirable.

Using Raptor on the upper stage however is less workable. Even Archimedes is really too big. If the first stage used Raptor, though, Rocket Lab could have used their design resources on perfectly sized methalox vacuum engine, where they also don't have the weight penalties of an engine designed for rapid reuse, given that they will be expended.

But this is all utterly hypothetical.

[Robotbeat]

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.

If it met all those things and was available to purchase, people would change their needs to be compatible. Raptor is that good.

[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?

[DanClemmensen]

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.

Absolutely correct for any organization with one or more of the following mandatory requirements:
  *"Anybody but SpaceX"
  *Must be an EU engine
  *Must be a Russian engine
  *Must be a Chinese engine
  *Must be developed in-house
Of course, an organization with any of these mandatory requirements must be prepared to compete with a superior launcher that uses Raptor.

[deadman1204]

Of course, an organization with any of these mandatory requirements must be prepared to compete with a superior launcher that uses Raptor.

Except its not as free of a marketplace as people imagine. Anything government centric will always use its own (russian, chinese, european, japanese, ect).

There are also companies out there that simply will not use spaceX no matter what (oneweb, amazon/kuiper).

Competition is only one factor, and not an overwhelmingly large one.

[DanClemmensen]

Of course, an organization with any of these mandatory requirements must be prepared to compete with a superior launcher that uses Raptor.

Except its not as free of a marketplace as people imagine. Anything government centric will always use its own (russian, chinese, european, japanese, ect).

There are also companies out there that simply will not use spaceX no matter what (oneweb, amazon/kuiper).

Competition is only one factor, and not an overwhelmingly large one.

You are agreeing with my post. You deleted the parts that state exactly what you stated.

[trimeta]

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.

Absolutely correct for any organization with one or more of the following mandatory requirements:
  *"Anybody but SpaceX"
  *Must be an EU engine
  *Must be a Russian engine
  *Must be a Chinese engine
  *Must be developed in-house
Of course, an organization with any of these mandatory requirements must be prepared to compete with a superior launcher that uses Raptor.

The bigger issue is that this is all hypothetical, since there's no reason to suspect SpaceX will ever sell Raptor engines to outside organizations. I agree that if other US-based launch providers could buy them for a reasonable markup over manufacturing costs, they definitely would (to TrevorMonty's concerns about "low operating costs or long life," I suspect Raptor would win as well), unless "maintain/develop in-house engine design/manufacturing expertise" was a priority worth losing out on one generation of engines for. But since Raptors aren't for sale, the question isn't "which engine do launch providers use," it's "which launch provider do payload customers use."

IMO the only interesting engine comparison is Archimedes vs. Prometheus, since they're so similar in design and both organizations need an engine ASAP, so pooling their resources (e.g., one paying the other to design and build engines) would potentially actually be beneficial.

[deadman1204]

Of course, an organization with any of these mandatory requirements must be prepared to compete with a superior launcher that uses Raptor.

Except its not as free of a marketplace as people imagine. Anything government centric will always use its own (russian, chinese, european, japanese, ect).

There are also companies out there that simply will not use spaceX no matter what (oneweb, amazon/kuiper).

Competition is only one factor, and not an overwhelmingly large one.

You are agreeing with my post. You deleted the parts that state exactly what you stated.

Crap, I had a total brain fart.  I started out quoting the wrong post to being with!

[ZachF]

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

If RL had a Raptor-quality engine at the price SX is paying, they wouldn’t be using Archimedes.

If Blue had a Raptor-quality engine at the price SX is paying, they wouldn’t be using BE-4.

If Arianespace had a Raptor-quality engine at the price SX is paying, they wouldn’t be using Prometheus.

Raptor is to big for Neutron. High performance doesn't mean low operating costs or long life both of which make for low cost RLV.


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Raptor-tier TWR/ISP would essentially double Neutron’s payload capacity in a semi-reusable configuration.

Most of the talk around Archimedes is PR fluff. Archimedes is a simple GG engine because that’s the only engine RL could develop is a reasonable amount of time.

Also, high performance doesn’t necessarily mean high operating cost or low life, as SpaceX’s engine manufacturing and engineering ability vastly exceeds RL’s.

I don’t think most people have mathed out Raptor vs other engines. It’s plain better. And post-Raptor will be even better than that.

[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.

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[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.

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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…

[Robotbeat]

Agreed totally. I think the reason Blue may have gone for staged combustion is because they thought they could handle it and that it was a necessary long term investment in what they wanted to achieve anyway.


Additionally, they were shooting for competing with RD-180 (although I’m not sure if that was a consideration early enough to influence their choice). A gas generator methalox engine might actually have no greater Isp than the RD-180 but would have the density penalty of methalox (kerolox is denser).

If you have effectively unlimited funding (as Blue kind of has) it’d feel way too tempting to choose staged combustion over gas generator.

EDIT: The TQ-12 is a gas generator first stage methalox engine for Landspace. It has a vacuum Isp of just 337s, the same or slightly lower than RD-180’s 338s Isp. It’s tough to see ULA wanting to switch to methalox if they have to take a performance hit.

[edzieba]

At the time BO started BE-4 development (2011) Raptor was still a notional Hydrolox staged-combustion engine, and only moved to Methalox in 2012. BO were in the position where they had the 'head start' in development, a cycle that was flight-proved (albeit not with that particular propellant), and likely assumed that if they were having a hard time with a 'mere' ORSC engine, the harder FFSC Raptor would take even longer. The wild spec changes of the early Raptor and the initial sub-scale testing probably strengthened that idea. By the time Raptor emerged as an engine sufficiently advanced to fly vehicles on - albeit one still in development - BO were locked into BE-4's design and had a supplier contract forcing them to deliver on the 2014-era specifications.
Reneging on the ULA supply contract is not even worth considering as an option, so they're stuck building BE-4 as it stands. And if they're building it, they may as well use it for New Glenn, even if they think a different design would be better in the long run, because they need something ASAP.

[JayWee]

At the time BO started BE-4 development (2011) Raptor was still a notional Hydrolox staged-combustion engine, ...

Is it even possible to do hydrogen FFSC or was it FRSC ?

[meekGee]

...
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…

Asymmetrical warfare...

This too should have been a very short thread.

[trimeta]

...
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…

Asymmetrical warfare...

This too should have been a very short thread.

Perhaps the real question should be "how well do each of these engines meet the needs of their respective projects?", rather than directly comparing them to each other. Although there's no particular reason such a question would belong in the Blue Origin subforum in particular.

[edzieba]

At the time BO started BE-4 development (2011) Raptor was still a notional Hydrolox staged-combustion engine, ...

Is it even possible to do hydrogen FFSC or was it FRSC ?

It was FRSC.

[Lemurion]

...
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…

Asymmetrical warfare...

This too should have been a very short thread.

Perhaps the real question should be "how well do each of these engines meet the needs of their respective projects?", rather than directly comparing them to each other. Although there's no particular reason such a question would belong in the Blue Origin subforum in particular.

I'm not sure why it had to be in this subforum either.

Speaking to your question, which I agree is far more relevant, I would say that both Raptor and Archimedes appear to be meeting the requirements of their respective projects fairly well. I'm less convinced regarding BE-4 as it has to balance ULA's requirements for Vulcan against Blue's internal requirements for New Glenn.

[ZachF]

At the time BO started BE-4 development (2011) Raptor was still a notional Hydrolox staged-combustion engine, ...

Is it even possible to do hydrogen FFSC or was it FRSC ?

FFSC is possible on hydrolox, it’s just not as huge of a performance boost as the hydrogen requires like 80% of the pump power anyway.

Even though Methalox requires slightly higher pump power for the oxygen as the methane, you could have probably designed a higher chamber pressure FRSC engine with less of an engineering headache as ORSC (no hot oxygen-rich gas).

I’m not sure if FFSC is possible with kerolox as you’d probably get coking problems on the kerosene side.

[Zed_Noir]

<snip>
I’m not sure if FFSC is possible with kerolox as you’d probably get coking problems on the kerosene side.

Is there any practical way to reduce the kerosene coking? Presuming a higher than usual development budget.

[zubenelgenubi]

Moderator:
Thread moved to Commercial Space Flight General board.

[Purona]

SpaceX needed a high thrust, high isp engine. An engine that worked well at both Sea Level and in a Vacuum. A Full Flow Staged Combustion engine was the right choice for them

Blue Origin just needed a first stage booster engine that could serve the, at the time, payloads and future payloads for LEO/GTO/Direct GEO. The Version 1 BE-4 engine with two variants and the version 2 BE-4 engine with a single variant serves those payloads.

There was no need for Blue Origin to build a full flow staged combustion engine when the BE-4 is perfectly capable of serving every mission so far while being reusable .... on paper.

At the moment the BE-4 doesn't need to be more powerful it needs to be more reusable, reliable, cheaper and easier to maintain

[rakaydos]

Looks like moving this thread to a more active forum was it's death knell.

[CorvusCorax]

Theres an old Be4 vs Raptor thread in the SpaceX section that despite all odds did not end up getting axed. It's not been active lately, but it has some interesting comparison data, at least on  the two main contestants.

https://forum.nasaspaceflight.com/index.php?topic=47513.0

[Tywin]

Is the BE-4 the most powerful methalox engine now?

https://twitter.com/torybruno/status/1533912186225049600

[trimeta]

Is the BE-4 the most powerful methalox engine now?

https://twitter.com/torybruno/status/1533912186225049600

That tweet was deleted, and corrected with the following, which suggests that its thrust hasn't changed from previously reported. Which has always been higher than the proposed thrust for Raptor...although Raptor 2 is closing in on that value.

https://twitter.com/torybruno/status/1534158256431681536

[edzieba]

550klbf = 2.5MN (or ~250 tonnes-force to be awkward).
For comparison, latest Raptor 2 number was "245 tons", which could be 245 tonnes or 222 tonnes (so 2.4MN or 2.18MN respectively).

Just use Newtons, please!

[edzieba]

550klbf = 2.5MN (or ~250 tonnes-force to be awkward).
For comparison, latest Raptor 2 number was "245 tons", which could be 245 tonnes or 222 tonnes (so 2.4MN or 2.18MN respectively).

Just use Newtons, please!

emphasis mine
Just a small typo
245 tons or 222 tonnes

Nope, I meant what I wrote. 245 tonnes (metric tons) = 222 tons (long tons), but it seems that the US uses a different ton (short tons) which would be 270 tons (short tons). ::EDIT:: Argh, other way around: 245 short tons = 222 tonnes, but 245 long tons = 250 tonnes. I hate non-SI units!

Another reason to use Newtons when the same phoneme can mean 3 entirely different units!

[JayWee]

Musk said in the ED interview he likes tones because he can see t/w immediately. So I suspect he meant metric tones.

[Robotbeat]

Note that power is thrust times exhaust velocity (i.e. basically Isp in proper units), so we can't tell if BE-4 is more powerful or not without that Isp figure. It's too close.

[Hog]

550klbf = 2.5MN (or ~250 tonnes-force to be awkward).
For comparison, latest Raptor 2 number was "245 tons", which could be 245 tonnes or 222 tonnes (so 2.4MN or 2.18MN respectively).

Just use Newtons, please!

emphasis mine
Just a small typo
245 tons or 222 tonnes

Nope, I meant what I wrote. 245 tonnes (metric tons) = 222 tons (long tons), but it seems that the US uses a different ton (short tons) which would be 270 tons (short tons). ::EDIT:: Argh, other way around: 245 short tons = 222 tonnes, but 245 long tons = 250 tonnes. I hate non-SI units!

Another reason to use Newtons when the same phoneme can mean 3 entirely different units!

Apologies, I thought you were attempting to convert tonnes to tons, but incorrectly wrote tonnes twice, the error was in my comprehension. 

[Tywin]

Only post, to remember that BE-4 is complete operational, now...

[Robotbeat]

Only post, to remember that BE-4 is complete operational, now...

Not the upper stage version, though, nor has it done a relight!

[Lars-J]

Only post, to remember that BE-4 is complete operational, now...

Not the upper stage version, though, nor has it done a relight!

The upper stage version of the BE-4 was shelved years ago, so that seems like a silly benchmark set up.

But hopefully we’ll see a relight in the next 12 months.

[meekGee]

Only post, to remember that BE-4 is complete operational, now...

Eyeroll.

An old army joke:

An elephant and a mouse are running in the desert, and the mouse looks up at the elephant and says: "Hey look how much dust we're kicking up!".

Someone summed it up in one of these threads: "Raptor is amazing, and BE-4 also doesn't suck".

BE-4 is operational because it only had to launch an EELV. It's hardly a badge of honor that it's "operational first".

I wish y'all would have a happy day with BE-4 succeeding to launch Vulcan, and not take it into some "we're winning the war" BS. That false sense of superiority, that's how ULA lost it, and you don't want that.

BE-4 launching Vulcan is like Merlin launching F9.  So if you want to do comparisons, it is 10 years late.

[Robotbeat]

Only post, to remember that BE-4 is complete operational, now...

Not the upper stage version, though, nor has it done a relight!

The upper stage version of the BE-4 was shelved years ago, so that seems like a silly benchmark set up.

But hopefully we’ll see a relight in the next 12 months.

My point is merely if we limit ourselves to first stage, no relight uses of each engine, then Raptor performed very well before BE-4 flew on Vulcan… and in fact Aeon-1 had a flawless first stage flight as well even earlier. That both Raptor and Aeon had upper stages which didn’t work should count against them when comparing to BE-4 which only has been used for a first stage so far, and only two engines at that, compared to 33 and 9, respectively.

[chopsticks]

Then war has already been won by Zhuque last year. Boom.

[volker2020]

hat both Raptor and Aeon had upper stages which didn’t work should count against them when comparing to BE-4

If we believe Musk (and I have no reason not too), the upper stage Raptors did work flawlessly. Only when they dumped oxygen to simulate a payload, it came to the explosion.

[daedalus1]

Then war has already been won by Zhuque last year. Boom.

Read the original question of the thread.
Nothing to do with first to orbit.

[meekGee]

Which engines will be better in weight efficiency, ISP, reliability, power, etc....

In short, which will be the best Methalox engine in this decade?

JD-1

TQ-12

Raptor

BE-4

Aeon-R

Archimedes

Prometheus

Dhawan-1

RD-0169

So why bring up certification even?  Your original question is clearly answered already, both by spec sheets and by real life performance.

[Robotbeat]

There’s a new contender from Impulse Space: Deneb. 15klbf staged combustion methalox engine for their Helios kick stage.

[JayWee]

Is Deneb the smallest staged combustion engine?

[lightleviathan]

I'm pretty sure that Launcher's E1 engine is smaller

[briantipton]

I'm pretty sure that Launcher's E1 engine is smaller

Launcher E1 is definitely smaller, but I don't know that it is staged combustion - the E2 is staged combustion but larger than Deneb. The first Soviet SC engine, S1.5400, was 15klbs so about the same as Deneb.

[Tywin]

Only post, to remember that BE-4 is complete operational, now...

Eyeroll.

An old army joke:

An elephant and a mouse are running in the desert, and the mouse looks up at the elephant and says: "Hey look how much dust we're kicking up!".

Someone summed it up in one of these threads: "Raptor is amazing, and BE-4 also doesn't suck".

BE-4 is operational because it only had to launch an EELV. It's hardly a badge of honor that it's "operational first".

I wish y'all would have a happy day with BE-4 succeeding to launch Vulcan, and not take it into some "we're winning the war" BS. That false sense of superiority, that's how ULA lost it, and you don't want that.

BE-4 launching Vulcan is like Merlin launching F9.  So if you want to do comparisons, it is 10 years late.

Why you always are so hateful to Blue?

[Tywin]

There’s a new contender from Impulse Space: Deneb. 15klbf staged combustion methalox engine for their Helios kick stage.

Thanks, yes and some companies from China, are development new methalox engine too...

And we have the Typhoon from Nyx and Ariane...

And the new methalox engine, from ISRO for the NGLV...

[meekGee]

Only post, to remember that BE-4 is complete operational, now...

Eyeroll.

An old army joke:

An elephant and a mouse are running in the desert, and the mouse looks up at the elephant and says: "Hey look how much dust we're kicking up!".

Someone summed it up in one of these threads: "Raptor is amazing, and BE-4 also doesn't suck".

BE-4 is operational because it only had to launch an EELV. It's hardly a badge of honor that it's "operational first".

I wish y'all would have a happy day with BE-4 succeeding to launch Vulcan, and not take it into some "we're winning the war" BS. That false sense of superiority, that's how ULA lost it, and you don't want that.

BE-4 launching Vulcan is like Merlin launching F9.  So if you want to do comparisons, it is 10 years late.

Why you always are so hateful to Blue?

I quote from that very post:
"I wish y'all would have a happy day with BE-4 succeeding in launching Vulcan, and not take it into some "we're winning the war" BS. That false sense of superiority, that's how ULA lost it, and you don't want that."

See?  Nothing against BO.  They had a good day.  It is posts like yours that start the "engine wars" and try to prove that not only did BO have a good day, but now are somehow winning the war, the tortoise passes the hare, and all that other BS.

You start an argument, and then you're upset you get a response?

[Tywin]

Only post, to remember that BE-4 is complete operational, now...

Eyeroll.

An old army joke:

An elephant and a mouse are running in the desert, and the mouse looks up at the elephant and says: "Hey look how much dust we're kicking up!".

Someone summed it up in one of these threads: "Raptor is amazing, and BE-4 also doesn't suck".

BE-4 is operational because it only had to launch an EELV. It's hardly a badge of honor that it's "operational first".

I wish y'all would have a happy day with BE-4 succeeding to launch Vulcan, and not take it into some "we're winning the war" BS. That false sense of superiority, that's how ULA lost it, and you don't want that.

BE-4 launching Vulcan is like Merlin launching F9.  So if you want to do comparisons, it is 10 years late.

Why you always are so hateful to Blue?

I quote from that very post:
"I wish y'all would have a happy day with BE-4 succeeding in launching Vulcan, and not take it into some "we're winning the war" BS. That false sense of superiority, that's how ULA lost it, and you don't want that."

See?  Nothing against BO.  They had a good day.  It is posts like yours that start the "engine wars" and try to prove that not only did BO have a good day, but now are somehow winning the war, the tortoise passes the hare, and all that other BS.

You start an argument, and then you're upset you get a response?

In what moment, I said, "winning the war, the tortoise passes the hare,"?

I am only talking about at, one amazing a very powerful methalox engine, that is already operative...


I hope this thread continues for many years, it is supposed to be something, to talk about all the methalox engines that now, dominate the ERA rocket....

In a future, 10-15 years, we can make a podium of the best methalox engine in 3 different categories:

Heavy

Medium

Small

[meekGee]

In what moment, I said, "winning the war, the tortoise passes the hare,"?

Here?
https://forum.nasaspaceflight.com/index.php?topic=47513.msg2417876#msg2417876

Here?
https://forum.nasaspaceflight.com/index.php?topic=47513.msg2556116#msg2556116

And all through the thread, all the talk about how BE-4 "made a cis-lunar flight", and "operational"  -  all distinctions without importance since it's only operational in EELV-like booster operation, and you know very well it never gets to orbit, it never relights.

So you start these arguments with unfounded claims, and when you get push back, you whine that people just "hate Blue".  No sale.  What you're doing is ruining a perfectly impressive first-launch performance on Vulcan, and drowning it in a bunch of drivel so the actual achievement is lost.

[Tywin]

In what moment, I said, "winning the war, the tortoise passes the hare,"?

Here?
https://forum.nasaspaceflight.com/index.php?topic=47513.msg2417876#msg2417876

Here?
https://forum.nasaspaceflight.com/index.php?topic=47513.msg2556116#msg2556116

And all through the thread, all the talk about how BE-4 "made a cis-lunar flight", and "operational"  -  all distinctions without importance since it's only operational in EELV-like booster operation, and you know very well it never gets to orbit, it never relights.

So you start these arguments with unfounded claims, and when you get push back, you whine that people just "hate Blue".  No sale.  What you're doing is ruining a perfectly impressive first-launch performance on Vulcan, and drowning it in a bunch of drivel so the actual achievement is lost.

For fan like you was lost since the begining....NO sale either...

Let's stop this here, and continue talking about ALL the other methalox engines...

[spacenut]

Blue is slow and started about the same time as SpaceX.  Blue is developing many different engines like, BE-3, BE-3U, BE-4, BE-7, with both metholox and hydrolox.  They also have worked on a moon lander, New Shepard, as well as New Glenn.

SpaceX has developed only 3 engines, the Draco/Super Draco, Merlin, and now Raptor.  They developed vacuum engines from Merlin and Raptor. 

Blue hasn't launched one of their own rockets to orbit yet.  SpaceX hundreds of Falcon 9/Falcon Heavies.  SpaceX should make orbit and be successful with Starship/Superheavy by the time Blue gets New Glenn to orbit. 

SpaceX focuses on a problem and gets the solution done or quickly does away with an unproductive idea.  Blue has been working on a lot of things, but seems to drag on and not get anything for an orbital launcher completed.  They did get New Shepard operational, but has had some bugs. 

As far as the Metholox engines, both BE-4 and Raptor are operational and work.  SpaceX just has to work out Starship/superheavy problems.  Engines are not one of them, they work fine.  So it is basically a tie on the two engines working.  Getting to orbit is another thing.  ULA knows how to build an expendable rocket as shown with Vulcan.  SpaceX also knows how to build a reusable, at least the first stage rocket.  Starship will follow.  When is New Glenn going to launch? 

[Robotbeat]

You forgot Kestrel and the Starship landing thrusters, whatever they're called.

[deltaV]

SpaceX has developed only 3 engines, the Draco/Super Draco, Merlin, and now Raptor.

Draco and Super Draco are two different engines. Super Draco has 177x the thrust of Draco.

[meekGee]

..  but back to Methalox engines.

BE-4 and Raptor are in the same class, and that's the only comparison that makes sense.  Everyone else is not in a "war" but rather in survival mode.

BE-4 was titled "operational", but in fact demonstrated less abilities than Raptor 2 did.

Obviously Raptor is manufactured in much higher quantities and lower price point.

While similar in thrust, Raptor is easily the more capable engine of the two, by any measure.

[ulm_atms]

Off-Topic but...

I just want to say that "war" is a way over used and a mostly, wrongly used word now a days.  What is being discussed seems to me to be competition.  War implies conflict....which this is NOT.

https://www.merriam-webster.com/dictionary/war

[edzieba]

Updated table with TQ-12:

-	Raptor	BE-4	TQ-12
Operate on test stand	Completed	Completed	Completed
Complete static fire	Completed	Completed	Completed
Ignite and lift off for flight	Completed	Completed	Completed
Complete first stage/booster burn successfully	Completed	Completed	Completed
Reignite for boostback	Partially Completed	No attempt	No attempt
Complete boostback burn successfully	Attempt failed	No attempt	No attempt
Reignite for landing	Partially Completed (upper stage only)	Not yet attempted	No attempt
Complete landing burn successfully	Partially Completed (upper stage only)	Not yet attempted	No attempt
Ignite for upper stage	Completed	No attempt	Completed
Complete upper stage insertion burn successfully	Attempt failed	No attempt	Completed
Ignite for in-orbit / deorbit burn	Not yet attempted	No attempt	?
Complete in-orbit / deorbit burn successfully	Not yet attempted	No attempt	?
Be re-used for flight	Not yet attempted	Not yet attempted	No attempt

[baldusi]

At the time BO started BE-4 development (2011) Raptor was still a notional Hydrolox staged-combustion engine, ...

Is it even possible to do hydrogen FFSC or was it FRSC ?

FFSC is possible on hydrolox, it’s just not as huge of a performance boost as the hydrogen requires like 80% of the pump power anyway.

Even though Methalox requires slightly higher pump power for the oxygen as the methane, you could have probably designed a higher chamber pressure FRSC engine with less of an engineering headache as ORSC (no hot oxygen-rich gas).

I’m not sure if FFSC is possible with kerolox as you’d probably get coking problems on the kerosene side.

Let me remind you that when using methalox, OR gives you like twice the power or FR. In hydrolox case it's different because you have something like 5 times the thermal power available on the FR side. And on kerolox you can't (in practice) do FR. So it is logical, in fact, to go OR for methalox. You actually need lower turbine temps for OR.
That's also the reason why it only makes real sense to do FF in methalox (or UDMH/N2H2). In hydrolox is possible, but the payoff is marginal compared to FR.
Regarding the thread topic, I think people underestimate the engineering bandwidth and strength of SpaceX propulsion team. Not Energomash nor KBKhA were able to do a full flow engine. And Rocketdyne spent a fortune on just a FF powerhead, but was never able to actually build a product around it.
SpaceX team not only can develop, buy they can build and test them with actual serial production. I can't stress how far ahead of everybody else they are. Even with all the money in the world, Blue still uses government testing stands. And Polyot was not able to serially produce the RD-191. To put into perspective, Merlin 1D family has had 3111 complete missions, with a single failure that didn't affected the mission. So yes, Raptor is heads and shoulders above the rest by much. But nobody can compare nor compete from nothing at all.
Whoever follows needs to do lots of cheap methalox engines first, to get the experience, and then we might see who attempts another full flow engine. One in the 1MN range would be ideal. But this is a discussion for the next decade.

[Darkseraph]

Off-Topic but...

I just want to say that "war" is a way over used and a mostly, wrongly used word now a days.  What is being discussed seems to me to be competition.  War implies conflict....which this is NOT.

https://www.merriam-webster.com/dictionary/war

Perhaps it should be renamed to a Special Propulsive Operation 

[laszlo]

...To put into perspective, Merlin 1D family has had 3111 complete missions, with a single failure that didn't affected the mission.

Tell that to Orbcomm.

[GreenShrike]

...To put into perspective, Merlin 1D family has had 3111 complete missions, with a single failure that didn't affected the mission.

Tell that to Orbcomm.

Flight 4 of the Falcon 9 v1.0, which carried a Dragon for  ISS resupply and Orbcomm-OG2 as a secondary payload, used Merlin 1C engines, not the Merlin 1Ds of the Falcon 9 v1.1+ vehicles. ;-)


As for the thread, I agree with Baldusi.

On the one hand, you have a compact, high-thrust full-flow methalox engine being churned out continuously by a factory line for extremely low single-digit millions of dollars, of which 30+ of them have successfully propelled their booster to staging.

On the other hand, you have none of that except a high-thrust methalox engine, of which two have successfully completed their flights.

I look forward to Blue demonstrating Merlin-like reliability as the New Glenn launcher grows into the heavy workhorse role it's meant for. The BE-4 is a solid step over the Merlin tech-wise (ORSC vs. gas generator) and size-wise, but it's also a step behind Raptor in terms of power cycle, thrust-density, and being designed-to-cost.

Reuse certainly helps mitigate the pain of high build costs, but with BE-4's cost being what it currently is, unfortunately losing a New Glenn booster is going to hit the pocketbook a lot harder than losing an F9 booster -- maybe even more than losing a Super Heavy. It's entirely understandable that Blue wants to start recovering them even from its first flight.

[laszlo]

Flight 4 of the Falcon 9 v1.0, which carried a Dragon for  ISS resupply and Orbcomm-OG2 as a secondary payload, used Merlin 1C engines, not the Merlin 1Ds of the Falcon 9 v1.1+ vehicles. ;-)

Oops.

[spacenut]

The title should have been "Competition" instead of war.  Competition is what companies do.  War is what politicians do when they control a country. 

[Tywin]

The title should have been "Competition" instead of war.  Competition is what companies do.  War is what politicians do when they control a country.

Agree, remember people that english is not my first language, and in the moment of the thread, I don't know that war, have this meaning so negative vs competition...

[trimeta]

The title should have been "Competition" instead of war.  Competition is what companies do.  War is what politicians do when they control a country.

Agree, remember people that english is not my first language, and in the moment of the thread, I don't know that war, have this meaning so negative vs competition...

80% of your posts and comments are attempts to stir up shit, don't hide behind the language barrier. (The other 20% are interesting links, I'll grant.)

[Tywin]

The title should have been "Competition" instead of war.  Competition is what companies do.  War is what politicians do when they control a country.

Agree, remember people that english is not my first language, and in the moment of the thread, I don't know that war, have this meaning so negative vs competition...

80% of your posts and comments are attempts to stir up shit, don't hide behind the language barrier. (The other 20% are interesting links, I'll grant.)

Guilty of the charge, for post shit, and all that, only for love the projects of Blue Origin, and the New Glenn, a terrible sin, for some in this forum...

[Tywin]

The title should have been "Competition" instead of war.  Competition is what companies do.  War is what politicians do when they control a country.

Agree, remember people that english is not my first language, and in the moment of the thread, I don't know that war, have this meaning so negative vs competition...

80% of your posts and comments are attempts to stir up shit, don't hide behind the language barrier. (The other 20% are interesting links, I'll grant.)

PD: In Spanish war meaning war, like in english, BUT is use a lot in competition comparasion, meaning too...

[Tywin]

Fixed thread title.

[Tywin]

I left this here, this infographic, very recent, show the NewSpace of China, and the engines of methalox of their future launchers...

[meekGee]

The title should have been "Competition" instead of war.  Competition is what companies do.  War is what politicians do when they control a country.

Agree, remember people that english is not my first language, and in the moment of the thread, I don't know that war, have this meaning so negative vs competition...

80% of your posts and comments are attempts to stir up shit, don't hide behind the language barrier. (The other 20% are interesting links, I'll grant.)

Guilty of the charge, for post shit, and all that, only for love the projects of Blue Origin, and the New Glenn, a terrible sin, for some in this forum...

You're doing it again.

[edzieba]

Updated table with TQ-12:

-	Raptor	BE-4	TQ-12
Operate on test stand	Completed	Completed	Completed
Complete static fire	Completed	Completed	Completed
Ignite and lift off for flight	Completed	Completed	Completed
Complete first stage/booster burn successfully	Completed	Completed	Completed
Reignite for boostback	Partially Completed	No attempt	No attempt
Complete boostback burn successfully	Attempt failed	No attempt	No attempt
Reignite for landing	Partially Completed (upper stage only)	Not yet attempted	No attempt
Complete landing burn successfully	Partially Completed (upper stage only)	Not yet attempted	No attempt
Ignite for upper stage	Completed	No attempt	Completed
Complete upper stage insertion burn successfully	Attempt failed	No attempt	Completed
Ignite for in-orbit / deorbit burn	Not yet attempted	No attempt	?
Complete in-orbit / deorbit burn successfully	Not yet attempted	No attempt	?
Be re-used for flight	Not yet attempted	Not yet attempted	No attempt

Updated:

-	Raptor	BE-4	TQ-12
Operate on test stand	Completed	Completed	Completed
Complete static fire	Completed	Completed	Completed
Ignite and lift off for flight	Completed	Completed	Completed
Complete first stage/booster burn successfully	Completed	Completed	Completed
Reignite for boostback	Completed	No attempt	No attempt
Complete boostback burn successfully	Completed	No attempt	No attempt
Reignite for landing	Attempt failed (booster)/Completed (ship)	Not yet attempted	No attempt
Complete landing burn successfully	Not yet attempted (booster)/Completed (ship)	Not yet attempted	No attempt
Ignite for upper stage	Completed	No attempt	Completed
Complete upper stage insertion burn successfully	Completed	No attempt	Completed
Ignite for in-orbit / deorbit burn	Attempt aborted	No attempt	?
Complete in-orbit / deorbit burn successfully	Attempt aborted	No attempt	?
Be re-used for flight	Not yet attempted	Not yet attempted	No attempt

[Tywin]

Can we have a comparison of the Archimedes vs Miranda* vs Aeon-R?

https://twitter.com/RocketLab/status/1787590838178254925


I know *Miranda is Kerolox...

[Solarsail]

Might or might not be an interesting note, but the Raptor series has seen at least one engine reused between flights:  SN-6 on Starhopper.  If we count the brief hops it did as flights.  The TQ-12 has also flown on a landing testbed, though only for a single flight.

[Hug]

Can we have a comparison of the Archimedes vs Miranda* vs Aeon-R?

Sure, I'm just doing a vac engine comparison just to simplify things for me.

Engine	Aeon R	Archimedes	Miranda
Thrust (kN)	1241	890	890
Vac ISP (s)	360*	367	328

*Aeon R Vac ISP is going off Aeon 1 Vac ISP. There are arguments that it might be lower, but eh they're probably putting some extra work into it. Miranda Vac ISP is really meh in the context of Merlin 1D hitting 346 or 348s as a gas generator. Thrust is obviously just by vehicle necessity, so it's hard to make meaningful comparisons. Dev timeline might be the other interesting metric, as that's what they're all racing towards. Definitive start dates might be hard to find though. All engines are obviously throttable, relightable and reusable; so that's kinda meaningless as well.

A reasonable set of LV engines but nothing truly special.

[edzieba]

Updated table with TQ-12:

-	Raptor	BE-4	TQ-12
Operate on test stand	Completed	Completed	Completed
Complete static fire	Completed	Completed	Completed
Ignite and lift off for flight	Completed	Completed	Completed
Complete first stage/booster burn successfully	Completed	Completed	Completed
Reignite for boostback	Partially Completed	No attempt	No attempt
Complete boostback burn successfully	Attempt failed	No attempt	No attempt
Reignite for landing	Partially Completed (upper stage only)	Not yet attempted	No attempt
Complete landing burn successfully	Partially Completed (upper stage only)	Not yet attempted	No attempt
Ignite for upper stage	Completed	No attempt	Completed
Complete upper stage insertion burn successfully	Attempt failed	No attempt	Completed
Ignite for in-orbit / deorbit burn	Not yet attempted	No attempt	?
Complete in-orbit / deorbit burn successfully	Not yet attempted	No attempt	?
Be re-used for flight	Not yet attempted	Not yet attempted	No attempt

Updated:

-	Raptor	BE-4	TQ-12
Operate on test stand	Completed	Completed	Completed
Complete static fire	Completed	Completed	Completed
Ignite and lift off for flight	Completed	Completed	Completed
Complete first stage/booster burn successfully	Completed	Completed	Completed
Reignite for boostback	Completed	No attempt	No attempt
Complete boostback burn successfully	Completed	No attempt	No attempt
Reignite for landing	Attempt failed (booster)/Completed (ship)	Not yet attempted	No attempt
Complete landing burn successfully	Not yet attempted (booster)/Completed (ship)	Not yet attempted	No attempt
Ignite for upper stage	Completed	No attempt	Completed
Complete upper stage insertion burn successfully	Completed	No attempt	Completed
Ignite for in-orbit / deorbit burn	Attempt aborted	No attempt	?
Complete in-orbit / deorbit burn successfully	Attempt aborted	No attempt	?
Be re-used for flight	Not yet attempted	Not yet attempted	No attempt

Updated:

-	Raptor	BE-4	TQ-12
Operate on test stand	Completed	Completed	Completed
Complete static fire	Completed	Completed	Completed
Ignite and lift off for flight	Completed	Completed	Completed
Complete first stage/booster burn successfully	Completed	Completed	Completed
Reignite for boostback	Completed	No attempt	No attempt
Complete boostback burn successfully	Completed	No attempt	No attempt
Reignite for landing	Completed	Not yet attempted	No attempt
Complete landing burn successfully	Completed	Not yet attempted	No attempt
Ignite for upper stage	Completed	No attempt	Completed
Complete upper stage insertion burn successfully	Completed	No attempt	Completed
Ignite for in-orbit / deorbit burn	Attempt aborted	No attempt	?
Complete in-orbit / deorbit burn successfully	Attempt aborted	No attempt	?
Be re-used for flight	Not yet attempted	Not yet attempted	No attempt