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In Tim's interview with Elon Musk, Elon mentioned[1] low combustion efficiency as one of the major disadvantages of aerospike engines compared to the more traditional bell nozzles used on Raptor.

I wonder if Pangea has done anything in an attempt to solve that problem.

[1]: https://youtu.be/cIQ36Kt7UVg?t=408

⬐ phkahler

>> Elon mentioned low combustion efficiency as one of the major disadvantages of aerospike engines

If you haven't seen the SpaceX presentation on their combustion CFD software, it's a must see. They have state of the art simulation capability in this area - better than any commercial offerings.

⬐ aero-glide2

Everyone keeps posting this, but there's no update on that video.

⬐ taneq

They seem kinda busy over there, maybe they have higher priorities?

⬐ bernulli

That was 6 years ago, hard to say what remained of that ambitious goal. Also, these guys aren’t with SpaceX anymore.

⬐ baq

Raptor has since exceeded its target performance, maybe they ran out of frontiers to explore?

⬐ bernulli

I don’t understand your comment. What does Raptor have to do with CFD method developments? What is the frontier? What does it mean to run out of frontiers? Shouldn’t there be more resources rather than fewer?

⬐ panick21_

I don't think they stopped development of that tech just because some people left.

They clearly invested massively in engine development from then on. I don't think they simply stopped.

And Raptor has turned into the best engine ever since then. Likely the used lots of simulation in development.

Reminds me of this interview with Elon Musk, where he talks about Conway's Law and how they mitigate it at SpaceX: https://youtu.be/cIQ36Kt7UVg?t=206

It's very hard to design an efficient system when the people writing the requirements and the people implementing them don't really understand or talk to each other.

Elon said it well in an interview regarding Starship development, “most common problem in engineering is optimizing something that shouldn’t have been built in the first place”, https://www.youtube.com/watch?v=cIQ36Kt7UVg

Broaden your view. You are not put on earth to write great code, but to solve real world problems. Software development is a means to an end, not the end itself.

⬐ tome

Relevant similar quotations: https://quoteinvestigator.com/2017/02/09/efficient/

⬐ afarrell

Sometimes though, the engineering exists to create art. Because we are all human and we all in our own way yearn to answer the question "What is beauty?"

Including the folks at Valve.

⬐ valand

Well, Elon and SpaceX has the luxury of having a total control of the product's technical requirement.

Most probably this is because Elon, being the CEO, has enough technical prowess to oversee both the real-world requirement and technical aspect of the product. This allows the company to streamline the practical/from-real-world requirement and the technical specification, therefore eliminating "things that shouldn't have been built in the first place".

This is luxurious because other tech company either does not have and/or does not realize it must procure.

One of my personal daydream is to be in a period where this streamlined real-world requirement and technical specification is common, not a luxury.

⬐ hallqv

Excuses. What organization your work for is a choice you've made. You need to make sure you work for a well functioning one, few things are more important. If you can't get hired by one, start one yourself.

⬐ valand

Not excuses. I'm pointing out that to achieve the streamlined real-world-tech-spec, you need that kind of person.

My wish is not only for my organization but for everybody. The world might be a better place if things are cheaper to maintain.

⬐ hallqv

You don't need to be Elon Musk to think hard about if you are optimizing for solving real world problems or something else. It's a habit of mind and the courage to change your circustances if you find yourself in a situation where it's not possible do things the right way (e.g. in a dysfunctional organization).

https://youtu.be/cIQ36Kt7UVg?t=421

> water-fueled space transport

After watching an Elon Musk interview in front of his starship he was saying - If anyone can show us that aerospikes are the way to go then please, do it. It'll be a gift.

https://www.youtube.com/watch?v=cIQ36Kt7UVg

This other company Arca has a 25-video series starting 2 years ago about their journey to build a hydrogen/oxygen (water) areospike engine. Really worth the watch. Skip to the last videos if you want to see live engine tests.

https://www.youtube.com/watch?v=L1hnImvI2gw

Agreed! It's also worth highlighting the bit where he asks Elon Musk: https://youtu.be/cIQ36Kt7UVg?t=382

    I've internally asked this question so many times,
    like, guys, shouldn't we maybe do an aerospike?

Musk focused on the high combustion efficiency of traditional combustion chambers, combined with the high efficiency of having two stages, as the reason why they won out. Jettisoning irrelevant fuel-containing mass as you go is great for efficiency and as a bonus it makes it easy to put sea-level-optimized nozzles on the bottom stage and vacuum-optimized nozzles on the top stage.

Here's a video on SSTO: https://www.youtube.com/watch?v=Sfc2Jg1gkKA

Elon talking about SSTO: https://www.youtube.com/watch?v=cIQ36Kt7UVg

He claims otherwise. His rockets seem to work quite well. https://youtu.be/cIQ36Kt7UVg?t=175

Also Gmail 1 day for the first prototype. An an aside I found Musk interesting talking about how they get the Starship type projects to progress quickly: https://www.youtube.com/watch?v=cIQ36Kt7UVg&feature=youtu.be...

>And one of the most fundamental errors made in advanced developments is to stick to a design even when it is very complicated, and to not strive to delete parts and processes.

etc

In the end of this video https://www.youtube.com/watch?v=cIQ36Kt7UVg he is more relaxed that I have ever seen. I don't think there is any acting in his presentations

⬐ canada_dry

Thanks, you're right. At the end, when he's talking geek-to-geek - so to speak - his thought process and speech seem much more aligned. https://youtu.be/cIQ36Kt7UVg?t=805

Here's an interesting interview the author did with Elon Musk: https://www.youtube.com/watch?v=cIQ36Kt7UVg

Fun to see how interested Elon is with the engineering of rockets, looks like he could talk for days if he had the time.

⬐ oxplot

He is the lead designer! So he must be interested quite a bit to do that on day-to-day basis.

⬐ TaylorAlexander

Yeah exactly. I think a lot of people don’t realize that. Elon is so busy and no other person with his level of power is really doing that kind of ground work. But I think about it this way: Elon can do whatever he wants, and he loves rockets. Being the lead engineer on the first Mars colony rockets (and first reusable first stages) is his life’s work. It’s what he wants to be doing.

⬐ tgtweak

This is such a good interview. Lots of engineer philosophy dropped here. Love his approach on thinking things are always wrong and to constantly question interfaces and standards.

⬐ speedplane

> This is such a good interview. Lots of engineer philosophy dropped here.

The interview is great, and it really highlights the difference in the way that founders and engineers think compared to those in the finance and commercial fields. If this was an investor interview, they'd be asking about deadlines and revenue projections. If it was a Joe Rogan interview, the questions would be vague questions about social, political, or philosophical repercussions. Those are all important questions, but they don't actually address what any business or organization is really trying to do. You can learn a lot more about a person or organization by speaking their language and letting them talk the way they are comfortable than by stuffing them into your own rubric of what they should be expected to say.

⬐ wolfram74

"All models are wrong, but some are useful"

https://en.wikipedia.org/wiki/All_models_are_wrong

⬐ AmericanChopper

Apart from climate models of course. Science is settled.

⬐ gbrown

Climate models are a perfect example of the above statement. They're not good enough to predict the detailed future with certainty (weather forecasts only go out for a few days), but they're useful and valid for reasoning about large scale trends.

⬐ caconym_

I wholeheartedly believe in anthropogenic climate change and I disagree with this comment with every fiber of my being despite not knowing which "side" you're actually on.

I'm actually kind of impressed.

⬐ AmericanChopper

I’m on neither side. I also wholeheartedly believe in anthropogenic climate change, but I think the commentary on climate science is about as ignorant and anti-scientific as the views espoused by young earth creationists. Climate models are flimsy as hell and have an atrocious track record of making predictions. Yet “the science is settled” (or a close approximation to it) is the only acceptable view in most circles. This gives climate change deniers a remarkably strong platform, because they can just say “climate scientists (or more often climate science communicators) are full of bs” and then point to countless examples where that is absolutely true. Science is never settled, in any case that you think it is, you’re not dealing with science, you’re dealing with an opinionated dogma. A statement which almost everybody would agree with, on any topic except climate change.

⬐ snowwrestler

Computer models are used to try to predict the local effects of climate change, not prove whether it’s real. The basic science is settled, and no one needed computers to do it. Heck the hypothesis was first proposed over 100 years ago.

Computer climate models have trouble returning accurate predictions for exactly the same reasons it’s hard to make accurate weather forecasts. They’re attempting to do things on the edge what we know is possible. Personally, I would not call that “flimsy as hell.”

⬐ jamiek88

Relativity is a model. Yet it is settled.

Still 'wrong' though.

⬐ AmericanChopper

Seems like a pretty creative use of the word ‘settled’.

⬐ Retric

F = M * A is never correct. Yet, it’s simple and useful enough in most situations to be ‘settled’ and people will probably still use it in 10,000 years. Thus, demonstrating these are different qualities when it comes to models.

⬐ AmericanChopper

The key feature of science is that all theories are open to further scrutiny and falsification. To say “the science is settled” is probably the least scientific statement you could possibly make. A deeply ironic position to take for people who’s key complaint about their detractors is that they don’t appreciate science.

⬐ Retric

Science as a search for truth cares deeply about accuracy, engineering doesn’t. Discovering say F=MA was wrong was a huge deal, but existing results still apply. New models fill in gaps, but the improved models needed to account for everything the old one correctly predicted.

So while science moves on, engineering does not care about the 15th decimal place. Which is why we keep getting value from approximations.

⬐ gbrown

When comparing two alternatives, we can most definitely conclude that the science is settled, at least until actual evidence to the contrary shows up. Being open to accepting new evidence in the future in no way means we can't act confidently on what we know now, taking into account our state of knowledge/uncertainty.

The science on a heliocentric solar system is settled. The science establishing a link between anthropogenic carbon emissions and average global temperatures is also settled - built on foundational chemistry and physics, supplemented with observational evidence here on Earth, and validated by the planetary science done to understand Venus's temperature.

Sure, there's a lot of remaining uncertainty about short term effects, but mostly in the category of "just how bad is it likely to get?"

⬐ inamberclad

That's why researchers should always report uncertainty bounds. On that note, I don't think I've ever heard a researcher give a definitive answer as to what climate change _will_ do. We can very precisely measure the change in ocean surface temperature and acidity and come up with reasonable guesses for the amount of CO2 added to the atmosphere every year, but the future always involves additional uncertainty.

⬐ AmericanChopper

This simply isn’t true. Climate science has an incredibly long history of failed predictions, with the less specific predictions being obviously more resilient to falsification. If you care about the existence of climate change deniers, then you should know who Competitive Enterprise Institute are, most writing on climate change denial can be traced back to their publications. The reason being that they have an essentially limitless supply of alarmist predictions that have been falsified.

https://cei.org/blog/wrong-again-50-years-failed-eco-pocalyp...

https://cei.org/blog/manufacturing-alarm-dana-nuccitellis-cr...

https://wattsupwiththat.com/2017/10/30/some-failed-climate-p...

Just look at all the other child comments, most of them immediately jumped to the defence of supposedly irrefutable climate models. The reason climate deniers have so much support is that climate scientists, their communicators and their advocates have little credibility outside the true believers. If you don’t want to take my word on it, here’s a Stanford study on this exact topic:

https://www.sciencedaily.com/releases/2019/10/191018112145.h...

> The biggest problem is communication. No one fucking communicates.

Elon Musk says something interesting about this here:

"Product errors reflect organizational errors."

https://www.youtube.com/watch?v=cIQ36Kt7UVg&feature=youtu.be...

He's specifically talking about how the product subsystems are effectively mapped out by the product departments and that they should try to interface with each other with minimal constraints.

But, my take was that there needs to be a LOT of communication between departments and an ongoing debate between them as well.

Edit: The more that I think about it...

This might a big reason why Musk companies defy the odds, and why it is so difficult for incumbents to catch up.

The over the air updates of Tesla are a good example of hardware & software departments working together to make something very difficult to compete with (if you're a regular old school siloed company).

⬐ Aeolun

Yeah, I’ve been trying to teach my organization that if the input to my team is crap, the chances of anything but crap coming out are fairly low.

  Crap >> Team >> Crap

We’re front-end, and basically the lowest part of the pipeline, so literally everyones crap gets dumped on us.

⬐ baq

On two occasions I have been asked, — "Pray, Mr. Babbage, if you put into the machine wrong figures, will the right answers come out?" In one case a member of the Upper, and in the other a member of the Lower, House put this question. I am not able rightly to apprehend the kind of confusion of ideas that could provoke such a question.

    Passages from the Life of a Philosopher (1864), ch. 5 "Difference Engine No. 1"

⬐ adadgar

Not dismissing what Elon said but it is commonly know as Conway's law: https://en.m.wikipedia.org/wiki/Conway%27s_law

Elon Musk is also a huge fan of Douglas Adams, as he mentioned again in his latest interview with Tim Dodd, the Everyday Astronaut: https://www.youtube.com/watch?v=cIQ36Kt7UVg

The Everyday Astronaut had a great interview with Elon Musk after the Starship presentation a few days ago. They spent a bit of time talking about how much progress the team had made in very little time, and Musk's take was that it took them an awful long time to finally ask the right questions - years. Once they had formulated exactly what they were trying to do and what the actual relevant constraints were, finding the right solutions and making very rapid progress was actually not all that complicated.

He talked about the tendency really good engineers have to spend a lot of effort optimising the design of things that shouldn't be there at all.

Finally he banged on hard about always questioning your design constraints. He pointed out that if you get given some design constraints by another team, you should always consider their validity since it;s very unlikely they are optimal. The converse assumption would be that they are always perfect, so looking at it that way there's no reason you should assume they are right from the start.

For anyone who worries about the sunk cost fallacy, bear in mind it was only about a year ago they decided to throw away all the investment they'd put into building a composite body, including a huge main body tool.

https://www.youtube.com/watch?v=cIQ36Kt7UVg

⬐ martyvis

I came here to write this same comment as well. I think Elon has great insight how to very quickly build from conception to reality, pruning off undesirable paths before they consume resources.

In that one interview with Tim, he explored very deep concepts about cross team collaboration, engineering process and project management that extend well beyond the rocket science I was expecting to hear about

⬐ oblib

Watched this last night. Pretty impressive.

Musk got asked some pretty good questions towards the end and seemed to have a solid grasp with his answers.

And that "Starship" is just about as cool as can be. He's got me sitting on on pins and needles waiting for the first launch.

Direct link to 3:30: https://youtu.be/cIQ36Kt7UVg?t=206

⬐ askytb

One of the most interesting interviews I've seen of him, props to Tim Dodd