Tom Mueller interview 02 May 2017

[oldAtlas_Eguy]

Cost of R&D per engine is related to number of engines manufactured. If the number was going to be only a few hundred then yes but the number of engines produced will be in the thousands. They have flown about 300 M!D already. By end of year they have flown another 150. Next year another 250. Then 300 Then 350. By EOY 2020 if all goes well they will have flown 1350 engines. $1B R&Dcost (It didn't cost that much or even close) is $.75M/engine. Development cost of $500M is $.37M/engine. If the extra cost is $200M over the normal development $500M vs $300M then the increase in cost per engine due to R&D is $.15M. But the decrease in cost per engine due to using the lower parts count is probably a lot more than that.

That sounds more like number of flights than number of engines built.

If they've built 3-400 engines with a lot of reflights, that makes the R&D more expensive than production costs.

Cheers, Martin

Yes reflight could easily keep the engine manufacture to 200 or less/yr. But counting this year by 2020 they would still have manufactured ~1000 engines. By mid 2020s it would be ~2000 engines. So even in worse case where engine manufacture is cut back to only 100/yr they still get to >1000 by mid 2020s.

[RedLineTrain]

Q:  Have any other production engines done "face shutoff"?

[cppetrie]

Science reporting gone wrong:

SpaceX's New Mini-Falcon 9, the Block 5, Will Re-Fly in a Day - Inverse
https://apple.news/AVU1upgaoQXK_bQSG9C-8Yg

This interview is now hitting more press sites, but this article gets almost every detail wrong. A Merlin burning methane and a mini F9 with a single one of them? FH is the big brother rocket headed to Mars? Wow, there's wrong, dead wrong and then there's this.

[Space Ghost 1962]

If they've built 3-400 engines with a lot of reflights, that makes the R&D more expensive than production costs.

Don't confuse "costing" with GAAP "categorization".

Considerable parts of M-1D development could fall under the "reuse" category, and not par of the fixed costs, as a one time expense, amortizable over the life of the program (or entire corporate existence even).

Q:  Have any other production engines done "face shutoff"?

Yes, many. Small engines, nothing on the scale of Merlin IIRC. To lower costs and increase reliability.

Not a problem with them, because to change the design isn't so difficult, so you get a rapid ROI by doing so.

[Nomadd]

 Didn't F1-3 fail because of all the fuel between the valve and the injector bleeding out after the valve closed, which would have been prevented by FSO?

[king1999]

This is ridiculous reading between the lines. One of those political hits from the competitors. I don't see that it has anything to do with SLS.

Mueller also criticizes the excessive price of NASA’s currently under construction Space Launch System, which is going to cost billions of dollars but not be reusable.

“If your rocket costs a billion dollars, even if you use it 100 times, it’s still going to be very expensive to use. So we set out to build low-cost rockets from the very beginning.”

Source http://www.inquisitr.com/4219361/spacex-employee-ridicules-completion-from-europe-ula-and-russia-but-spares-blue-origin/

[Proponent]

With regards to the mixture ratio range of 3.6 - 3.8. A mixture ratio of 3.6 has ~10% excess fuel where as 3.8 has ~5%. Where it ends up will depend on combustion efficiency trends. It is easier to get high combustion efficiency with a larger excess of fuel, harder with lower excess, and really hard at stoichiometric. They may even allow for tuning between these mixture ratios for different uses. For example, the Mars burn will favor ISP over density*ISP, which the booster will favor.

Ideally, mixture ratio changes even during a burn.

[ArbitraryConstant]

This is ridiculous reading between the lines. One of those political hits from the competitors. I don't see that it has anything to do with SLS.

Mueller also criticizes the excessive price of NASA’s currently under construction Space Launch System, which is going to cost billions of dollars but not be reusable.

“If your rocket costs a billion dollars, even if you use it 100 times, it’s still going to be very expensive to use. So we set out to build low-cost rockets from the very beginning.”

Source http://www.inquisitr.com/4219361/spacex-employee-ridicules-completion-from-europe-ula-and-russia-but-spares-blue-origin/

What other rocket costs a billion dollars?

[philw1776]

Wasn't the cost of a shuttle launch a billion dollars or so?

[Space Ghost 1962]

Didn't F1-3 fail because of all the fuel between the valve and the injector bleeding out after the valve closed, which would have been prevented by FSO?

Think Tom was still in the "TRW engineer" mode at that time, attempting to prevent failure by minimizing risk.

FSO wasn't even an option at that point.

Now, one of the things that happens when you do *any* program/project/start-up/... is that you have a moment when you do a retrospective (IMHO, a reduced form of that brought about the discussion he talks about in this intv).

The "what if we've known what we knew now" moment. Except that's impossible. But, let's go with that. As speculation.

First, to have gotten roughly to something approximating M1-D (which is what you're saying) as the first engine, you'd have traded off likely more years of development, along with a ton of luck, and a lot of Musk's notably short patience reserve (boxes of Xanax).

Yes, it likely would have been more reliable, so your first two F1 launches would likely have not had booster issues. Don't think that it would have hidden more and different issues. But likely you'd still have the learning curve for launch operations, and the recontact issues with the second stage. And engine/stage recovery would still have been non existent, although you'd have had much more margin for recovery to work with, and a faster development cycle for accelerating everything that followed.

Note that path would be more like what you're seeing with SABRE development cycle.

Don't think it would have survived Musk's patience, nor that Tom's team would have been as effective. Having orbitted a paying payload changed them from an incapable organization into a capable one IMHO.

You can't shortcut things.

[rockets4life97]

What other rocket costs a billion dollars?

ITS. Musk said it would cost 10 billion to develop.

[ArbitraryConstant]

What other rocket costs a billion dollars?

ITS. Musk said it would cost 10 billion to develop.

Talking about unit cost for a launch, not cost to develop.

[AncientU]

The comments from Mueller gives the impression that the M1D has hit all three items instead of just 2 in the cost, performance, reliability tradeoff. This is in itself very significant and also important for SpaceX. They have a very low cost engine with high performance and high reliability. Something that no one else in the US industry has even come close to. Which is why the Atlas V uses the low cost, high performance, high reliability RD-180 from Russia, the only other engine in use in the US that hits all three points.

This goal of hitting all three for the Raptor is also encouraging. Using lessons learned and piling the difficulty into development to be able to make such an engine instead of compromising on operational costs to keep development costs down. Musk has it right. If your going to fly lots of them and want to lower operational costs have good or high performance and high reliability, don't push off doing the right things in development for reducing the development costs.

I think hitting all three is the baseline standard...

What? The conventional approach is "cost, performance, reliability: pick two". Hitting all 3 is rare indeed.

Also, while the marginal cost per engine may be low, you have to amortize the development cost, and I get the impression the quoted low cost doesn't take that into account. This quote suggests development cost will have been high:

Musk convinced Mueller of using this method despite Mueller explaining what it is and how it increases complexity of R&D and increased costs due to blowing lots of hardware up before mastering the method.

What is conventional about EM's approach to problem solving?
Falcon design effort didn't settle for two, nor did Tesla... path chosen reduces to a value judgement of the person driving a development program.  Those that are driven by a committee usually settle for much less.

Hitting all three is only rare because most designers/manufacturers/committees don't try.

Note: The cliche is "Faster, Better, Cheaper -- pick two"

[king1999]

This is ridiculous reading between the lines. One of those political hits from the competitors. I don't see that it has anything to do with SLS.

Mueller also criticizes the excessive price of NASA’s currently under construction Space Launch System, which is going to cost billions of dollars but not be reusable.

“If your rocket costs a billion dollars, even if you use it 100 times, it’s still going to be very expensive to use. So we set out to build low-cost rockets from the very beginning.”

Source http://www.inquisitr.com/4219361/spacex-employee-ridicules-completion-from-europe-ula-and-russia-but-spares-blue-origin/

What other rocket costs a billion dollars?

If you watch the video, TM clearly referred to the importance of keeping the cost down even for reusable rockets.
So he just put an theoretical number out there for a high cost reusable rocket. And since SLS is not reusable, that number have nothing to do with it.

Those crooks out there just tried to manufacture a rumor that SpaceX is criticizing SLS in public and hoped that fell on some senator's ears.

[MikeATL]

Science reporting gone wrong:

SpaceX's New Mini-Falcon 9, the Block 5, Will Re-Fly in a Day - Inverse
https://apple.news/AVU1upgaoQXK_bQSG9C-8Yg

This interview is now hitting more press sites, but this article gets almost every detail wrong. A Merlin burning methane and a mini F9 with a single one of them? FH is the big brother rocket headed to Mars? Wow, there's wrong, dead wrong and then there's this.

Just read it here https://www.inverse.com/article/31575-spacex-falcon-9-24-hour-reflight
Wow, is right... this piece has so much wrong with it.  Is it even worth the time to contact the writer to offer corrections?

[punder]

What other rocket costs a billion dollars?

ITS. Musk said it would cost 10 billion to develop.

Talking about unit cost for a launch, not cost to develop.

In fact one of the slides from the ITS reveal says $62M per Mars flight (eventually).

[RedLineTrain]

Yes, many. Small engines, nothing on the scale of Merlin IIRC. To lower costs and increase reliability.

Not a problem with them, because to change the design isn't so difficult, so you get a rapid ROI by doing so.

Thanks, Space.  Does it reduce any weight?

Whets my appetite for more details on Raptor...

[Space Ghost 1962]

Does it reduce any weight?

Not really. Just gets rid of moving parts. And easier to test.

[envy887]

...* 800 lbs is 340-385 kg.

340 kg/s is still significantly higher than expected for Merlin.

[Space Ghost 1962]

Aneutronic fusion has a much higher Coulumb barrier.

There's also Bremsstrahlung losses, which AIUI is an even bigger problem. The energy comes out as kinetic energy in charged nuclei from each fusion. Because they're charged they emit x-rays as they interact with the rest of the plasma, and the plasma is optically thin to x-rays. This makes it hard to reach Q=1 (breakeven), especially with magnetic confinement.

Along with a few other things, where the X-ray optical density of the plasma is insufficent. This comes during and after alpha heating. Yeah, lot more too.

Start a thread elsewhere please please please.