Author Topic: BE-5 speculation  (Read 8156 times)

Offline J-V

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BE-5 speculation
« on: 04/14/2016 12:11 pm »
Now that Blue Origin's BE-4 is approaching full size testing, would it be time to start speculating what their next step in engine development will be. Let's assume that the new engine will be called BE-5. What are your opinions on the following topics(or on your own):

- Will there ever be a BE-5?
- Jeff Bezos has said that they are using medium performing versions of high performing architectures. Does this mean methalox full flow staged combustion, or could it be tripropellant methahydrolox? Or maybe a new stage combustion upper stage engine?
- How powerful will this engine be? Direct BE-3/4 replacement or something bigger?

Yes, I know this is pure speculation without any facts. If you are not okay with such topics, move to the next topic please. Or if you are a mod, feel free to remove this ;)

Offline WBY1984

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Re: BE-5 speculation
« Reply #1 on: 04/14/2016 12:20 pm »
BE-4 is already a powerful engine. Is there any reason to assume that they will develop anything afterwards in the short to medium term? Just refine BE-4 and cluster it if needed.

Offline J-V

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Re: BE-5 speculation
« Reply #2 on: 04/14/2016 12:29 pm »
BE-4 is already a powerful engine. Is there any reason to assume that they will develop anything afterwards in the short to medium term? Just refine BE-4 and cluster it if needed.

It is powerful, but the ISP is kinda low. There's a lot of improvement available in that area. Of course if it increases the weight of the engine significantly, it might not be worth it for the first stage.

Offline WBY1984

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Re: BE-5 speculation
« Reply #3 on: 04/14/2016 12:35 pm »
Where did you find information on specific impulse?

Offline J-V

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Re: BE-5 speculation
« Reply #4 on: 04/14/2016 12:49 pm »

Offline RonM

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Re: BE-5 speculation
« Reply #5 on: 04/14/2016 12:54 pm »
BE-4 is already a powerful engine. Is there any reason to assume that they will develop anything afterwards in the short to medium term? Just refine BE-4 and cluster it if needed.

It is powerful, but the ISP is kinda low. There's a lot of improvement available in that area. Of course if it increases the weight of the engine significantly, it might not be worth it for the first stage.

That was to keep costs low and increase number of flights. At some point, increasing performance greatly increases cost and decreases reliability. Resusable rockets need to be more like a truck and less like a sports car.

Offline J-V

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Re: BE-5 speculation
« Reply #6 on: 04/14/2016 12:58 pm »
BE-4 is already a powerful engine. Is there any reason to assume that they will develop anything afterwards in the short to medium term? Just refine BE-4 and cluster it if needed.

It is powerful, but the ISP is kinda low. There's a lot of improvement available in that area. Of course if it increases the weight of the engine significantly, it might not be worth it for the first stage.

That was to keep costs low and increase number of flights. At some point, increasing performance greatly increases cost and decreases reliability. Resusable rockets need to be more like a truck and less like a sports car.

Correct me if I'm wrong, but isn't e.g. FFSC offering better performance with more room for reusability than ORSC?

Offline RonM

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Re: BE-5 speculation
« Reply #7 on: 04/14/2016 01:33 pm »
BE-4 is already a powerful engine. Is there any reason to assume that they will develop anything afterwards in the short to medium term? Just refine BE-4 and cluster it if needed.

It is powerful, but the ISP is kinda low. There's a lot of improvement available in that area. Of course if it increases the weight of the engine significantly, it might not be worth it for the first stage.

That was to keep costs low and increase number of flights. At some point, increasing performance greatly increases cost and decreases reliability. Resusable rockets need to be more like a truck and less like a sports car.

Correct me if I'm wrong, but isn't e.g. FFSC offering better performance with more room for reusability than ORSC?

I don't know. You should ask Blue's engineers about that. I'm pretty sure they know more about rocket engine design than we do.

Design teams make decisions based on many factors beyond pure performance. What is the factory capable of producing, how much will it cost to upgrade production, are major design changes to increase performance worth the effort, will the boss sign the check, etc.

From my experience in IT, will the boss sign the check was the biggest factor.

Offline Tev

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Re: BE-5 speculation
« Reply #8 on: 04/14/2016 01:35 pm »
Yes, if Blue chooses to make another engine and SpaceX proves that FFSC is workable without too big issues, Blue's next engine will probably be FFSC, if they will still exist.

Too many ifs. It's just too soon to speculate about anything . . . You should have waited with this thread 4-7 years more.

Offline R7

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Re: BE-5 speculation
« Reply #9 on: 04/14/2016 02:08 pm »
BE-5 will be pressurefed methalox in the 70-100ish kN range with TEA/TEB autoignition feature. It will be called SuperKraken. It will become the standard solution in several Blue threads.

There will be a miniature ~500N version too, called Kraken.
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Online TrevorMonty

Re: BE-5 speculation
« Reply #10 on: 04/14/2016 04:07 pm »
Not sure if BE5 will necessary be bigger but Blue will need to do something with its propulsion team. Maybe a smaller high performance replacement for RL10 for a lunar lander.

Edited. An aerospike engine.
« Last Edit: 04/14/2016 04:18 pm by TrevorMonty »

Offline J-V

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Re: BE-5 speculation
« Reply #11 on: 04/14/2016 07:09 pm »
Yes, if Blue chooses to make another engine and SpaceX proves that FFSC is workable without too big issues, Blue's next engine will probably be FFSC, if they will still exist.

Too many ifs. It's just too soon to speculate about anything . . . You should have waited with this thread 4-7 years more.

Are you certain? In seven years we might already have BE-5. The development of BE-3 started around 2010, and BE-4 at 2011 (source Wikipedia). BE-3 was acceptance tested a year ago, BE-4 is now in prototyping, and it should fly by 2019. Does the team that developed these engines in parallel now sit idling, have they left BO, or are they doing something new? If they are still in the company, I'd say that they are working with a new engine.

Offline J-V

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Re: BE-5 speculation
« Reply #12 on: 04/14/2016 07:14 pm »
Not sure if BE5 will necessary be bigger but Blue will need to do something with its propulsion team. Maybe a smaller high performance replacement for RL10 for a lunar lander.

Edited. An aerospike engine.

I doubt they will do a lander. Jeff mentioned in http://www.geekwire.com/2016/interview-jeff-bezos/  interview, that they are going to do transportation only, and payloads will be handled by others. Of course a lunar lander could be considered to be part of transportation infra, so...

Now that you mentioned aerospikes: does anyone know how easy it is to throttle an aerospike engine? Flow separation shouldn't be a problem, but are there limitations with combustors or turbopump? Also how good they are from reusability's point of view? I could imagine that re-entry shouldn't be a problem at least with such a shape, if a bell nozzle can handle it also.

Offline J-V

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Re: BE-5 speculation
« Reply #13 on: 04/14/2016 07:15 pm »
BE-5 will be pressurefed methalox in the 70-100ish kN range with TEA/TEB autoignition feature. It will be called SuperKraken. It will become the standard solution in several Blue threads.

There will be a miniature ~500N version too, called Kraken.

And this will take us to the Mun. Or bust.

Offline DJPledger

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Re: BE-5 speculation
« Reply #14 on: 04/14/2016 09:34 pm »
BO have said they want to build LV's bigger than anything that has ever been built before. So a BE-5 could be a >F-1 thrust LOx/LCH4 engine possibly FFSC to keep the no. of 1st stage engines on their future BFR to a reasonable value. I don't think that BO wants to dev. an N-1 style vehicle and Bezos says that turbopumps and thrust chambers scale well to large sizes.
« Last Edit: 04/14/2016 09:35 pm by DJPledger »

Offline Lemurion

Re: BE-5 speculation
« Reply #15 on: 05/10/2016 03:30 pm »
Given what little we currently know about BE-4, BE-5 is pure speculation. Having said that, I'm going to throw my hat in the ring with the idea that it's going to be a larger derivative of the BE-4.

It's conservative, but given the direction Blue is going in I think anything else would be a real stretch. Bezos seems to prefer bigger engines over more engines, so going for a larger engine that leverages the same technology and development path is the only thing that really makes sense.

The only concern I can see is that with propulsive landing you need really deep throttling and I question how deep they can throttle a much bigger engine. As it is I have questions about how easily Blue will be able to throttle BE-4 for landing, and a bigger BE-5 would be worse. Right now it appears that SpaceX can throttle down to about 40% on Merlin, which is about 4.5% of total thrust, and they still need to perform a hoverslam.

Depending on the number of engines, a BE-5 powered booster might need to either throttle a lot lower than 40%, add a separate braking engine, or go for a really ridiculous hoverslam landing.

BE-5 is going to be fascinating, not just for the technology but how they use it.

Offline RocketGoBoom

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Re: BE-5 speculation
« Reply #16 on: 05/10/2016 06:25 pm »
Doesn't a larger engine (BE-4 or BE-5) have difficulty throttling on the lower end to succeed with a controlled landing?

I think one of the keys to the Falcon 9 landing success is the ability to use between 1-3 of the 9 engines during the final landing burn. The Octaweb placement of the engines allows SpaceX to fine tune the thrust to control the landing.

How would that control be maintained with only two BE-4 engines? Even if they only used one BE-4 (or BE-5) for landing, it wouldn't be in the center of the stage. it would be offset a bit.

I don't think enough credit is being given to the flexibility provide by having 9 engines in the Octaweb design.
I am sure there are other solutions to achieve the landing. But I am wondering how BE-4 or BE-5 sized large engines will do it.

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