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SpaceX installed 29 Raptor engines on a Super Heavy rocket last night

arstechnica.com

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Re: SpaceX installed 29 Raptor engines on a Super Heavy rocket last night

#371

Post by h0l0cube »

practice9 wrote: post #359
h0l0cube wrote: post #330

Earlier quoted context omitted.

For the amount of downvotes I received, is this the best rebuttal anybody can come up with?

There is nothing to rebut. Financially and ecologically this is not worse than manufacturing products in China and shipping them all over the world, or usual stuff like tourism, cloud computing etc. I would argue that Starship is even more ecological than the other rockets, as it requires a cleaner fuel than Falcon (methane vs kerosene) and should be fully reusable (i.e. no tossing the rocket in the ocean and hoping…

> There is nothing to rebut.

And yet nothing in any response so far counters my claim that capital expenditure on space projects will likely increase exponentially. The only claim I made, and the one I was downvoted for.

> I would argue that Starship is even more ecological than the other rockets

Methalox combusts to CO2. As the burgeoning space industry scales up exponentially, so will the emissions.

https://everydayastronaut.com/wp-content/uploads/2020/03/Roc...

> If we manage to bootstrap space manufacturing, benefits for ecology, biology and material science are also self-evident.

Not 100% self-evident. Apart from how infeasible this is from the outset, once deployed at scale it would require transporting millions of tons of goods and raw materials back and forth against the gravity of the earth.

Not my domain, but I'm not sure there's a combustible fuel that could have the energy density to do this and not pollute the atmosphere (happy to be corrected on this). It seems we need to find a completely new means of propulsion (or offsetting with carbon capture) before we could have a green space industry.

Re: SpaceX installed 29 Raptor engines on a Super Heavy rocket last night

#372

Post by cryptonector »

TheOtherHobbes wrote: post #338
cryptonector wrote: post #312

Earlier quoted context omitted.

Malthusians exist. They think we're running out of oil, soil and arable land, fresh water, and... just about everything. The logic is that since population growth is exponential, we really could run out of resources. And... that's both totally correct and totally wrong. Totally correct: because yeah, duh, if we had 1 trillion people... Totally wrong: because in fact the arc of evolution of fertility rates, population…

Well, quite. Climate change also exists. So do resource limits. Something that doesn't exist is the science of living outside of an existing planetary ecosystem. Do some research on how much is understood about creating a stable ecosystem out of sand, metal ore, and water. You'll find it's a good approximation to zero. Flag wavers think it's all about building giant rockets, planting a flag - and boom. Colony! Astero…

> So until that changes, running your own planet - the one you got for free, and which was working fine already - as if you're trying to test it to destruction to find out just how stable it really is, is an unbelievably dumb thing to do.

Note that unstated in the quoted text is a strong assumption or implication that we are "trying to test [the planet] to destruction ..." with our 8bn people. It's hard escape a soupçon that when someone says or implies that, they really resent most of that 8bn people, maybe to the point where they'd be ecstatic if they got wiped out. I'm not saying you do, but it's a pretty gross feeling I get when I see that line of argument.

And look, if fertility rates for the whole world were 8 and trending upwards with the current 8bn, then I think I would be panicking myself, and agreeing with you, and predicting ecological disaster, terrible wars, etc. But we're not.

Almost throughout the entire world, fertility rates have crashed below replacement rate. Some cases are fairly surprising, like Iran's, which had a fertility rate of 8 in 1978 and has been below replacement rate for a number of years.

The reasons for fertility rates spiking in the 20th century and then dropping so far so fast are very, very well understood. It even used to be fashionable to talk about that around here, but not now -- now the Malthusian narrative seems to be in full swing without regard to the actual facts of global population pyramid (why??):

- enormous technological and medical advances lowered child mortality rates and increased life expectancy very quickly in the 20th century

- but it took time for the number of children people had in suddenly wealthy countries to drop to match the new reality

- political changes (and possibly pushing even remotely close to the planet's carrying capacity) have caused economic pressures that have driven young people to reduce their fertility, postpone family formation, or forgo family formation altogether

- those add up to us now being about to enter a negative population growth regime

For an example of political changes that have caused such pressures see Social Security and programs like it around the world. Because those programs make caring for the current generation of retirees the burden of the current generations of workers, that puts a not-neglible economic pressure on the working generations, and as fertility rates drop, that pressure increases -- a vicious (or perhaps virtuous, if you like) cycle.

Re: SpaceX installed 29 Raptor engines on a Super Heavy rocket last night

#373

Post by cryptonector »

throwaway316943 wrote: post #370
TheOtherHobbes wrote: post #338

Earlier quoted context omitted.

Well, quite. Climate change also exists. So do resource limits. Something that doesn't exist is the science of living outside of an existing planetary ecosystem. Do some research on how much is understood about creating a stable ecosystem out of sand, metal ore, and water. You'll find it's a good approximation to zero. Flag wavers think it's all about building giant rockets, planting a flag - and boom. Colony! Astero…

> these are all beyond hard I seem to remember some guy saying something about that. We’ve never let the fact that something doesn’t exist yet stop us. We are a species of inventors. We didn’t stay huddled naked in caves because they work and we got them for free. We aren’t meant to be like the rest of the ecosystem that mutely accepts its fate. We know we can die but we also reject the natural order of succumbing to…

A voice of reason. Thank you.

Indeed, when we lived in caves, there were only so many of them. We totally blew past the cave sustainability model thousands of years ago.

I'm not saying we should be cavalier about pushing current limits, but I also wouldn't be cavalier about doing things to hurt today's humans due to fears that are not well founded (because, again, negative population growth is now baked in to the world population pyramid, so that soon we won't be pushing the planet's limits any longer).

Re: SpaceX installed 29 Raptor engines on a Super Heavy rocket last night

#374

Post by T-A »

throwthere wrote: post #179
SahAssar wrote: post #133

Earlier quoted context omitted.

SpaceX has had very impressive successes, some government programs have failed or run over budget. Some government programs were also impressive, both in the US and abroad. I think we can all agree on those points. The point of the GP that I (and I think many others) react to is the "Only in America things like this can happen" part. I just don't get American exceptionalism I guess.

Do you have some other country in mind that could support a nascent space company?

https://tracxn.com/explore/NewSpace-Startups-in-China

Re: SpaceX installed 29 Raptor engines on a Super Heavy rocket last night

#375

Post by merpnderp »

lucideer wrote: post #252
merpnderp wrote: post #75

Earlier quoted context omitted.

Who looks at a rocket and thinks "Hmm, I bet the engineers could have gone with a more efficient design, but they decided to go with a dick?" Like do people really think that there's better shapes to go with? And if people really believe this, what part of our public education system failed them most? Because my money is on critical thinking.

Well if you're really looking for alternative shapes, one of the Mars fantasists I was alluding to actually went to space recently in a rather flat triangular vehicle. Which is of course completely irrelevant when one is evoking a male ego megaphor and not opening an engineering discussion on aerodynamics. I would have hoped critical thinking could also help with that distinction in topics. Fwiw, I'm at least glad th…

Lol, the last time NASA built a space plane to do real work in space, it was grossly inefficient than the previous giant dick it replaced, wildly more dangerous, and NASA had to attach it to three other dicks just to get it to space.

Face it man, people making fun of dick shaped rockets are seeing dicks where no one else is seeing them and calling themselves clever.

Re: SpaceX installed 29 Raptor engines on a Super Heavy rocket last night

#376

Post by cryptonector »

mucholove wrote: post #358
cryptonector wrote: post #312

Earlier quoted context omitted.

Malthusians exist. They think we're running out of oil, soil and arable land, fresh water, and... just about everything. The logic is that since population growth is exponential, we really could run out of resources. And... that's both totally correct and totally wrong. Totally correct: because yeah, duh, if we had 1 trillion people... Totally wrong: because in fact the arc of evolution of fertility rates, population…

On the environment and fauna, animals are going extinct (like the white rhino) so yes, we are running out of stuff. Trees—like Dominican mahogany grow really slowly and now there are so few of them we have basically run out. I can name several other examples—most notably Guayacan. There is a bunch of scarcity and destruction. I’m pretty sure we can fix them—but for the trees and the animals it’s unlikely that I get t…

Sustainability requires wealth. You mention Dominican mahogany. Have you ever seen pictures of the border between Haiti and the Dominican Republic? They're really shocking! No trees in sight on the Haitian side; forest as far as the eye can see on the Dominican side. Why is that? Because Haiti is so much poorer than the Dominican Republic that trees are burned for firewood.

The environment is cleanest and best in richer countries because rich people can afford to care about it. That's right, poor people who worry about where their next meal is going to come from could not care less about the environment.

So if you want the 8bn people of this planet to care for it, we have to make them richer than they are.

Re: SpaceX installed 29 Raptor engines on a Super Heavy rocket last night

#377

Post by pharmakom »

cryptonector wrote: post #362
pharmakom wrote: post #324

Earlier quoted context omitted.

Not a Malthusian, but I’m very worried about the amount of resources we are using. We already lack the carbon budget and farming capacity for the world’s population to live to the standard of an average US citizen. There might be enough space and enough atoms, but we don’t yet have the capability to direct it into sustainable quality of life for all.

Did you know that total land under agriculture has been trending down for several decades? Would that put you at ease?

But environmental destruction is way up.

A good example is river health. We can provide more meat with high density grazing. But the waste products have to go somewhere, so the farmers spread them across their fields. Now when it rains, these run into the rivers and we get algae bloom. Majority of rivers in UK are now dying, for example.

Have we discovered a sustainable way of producing more meat in less space? I hope so. But perhaps we are destroying natural systems whose benefit to us has not been properly quantified, in a way that will be extremely difficult to reverse.

Modern agriculture has enabled us to support a larger world population with less labour and less space, but can we continue as we are for another 50 years?

Re: SpaceX installed 29 Raptor engines on a Super Heavy rocket last night

#378

Post by rpmisms »

908B64B197 wrote: post #217
rpmisms wrote: post #191

Earlier quoted context omitted.

There was also a recent incident in Virginia: (Virginia Drops Advanced Math)[ https://www.msn.com/en-us/money/careers/virginia-to-drop-adv... ] This disgusts me. Some kids are stupid (Apologies for blunt language, but it's true, life is unfair.) or have poor home lives, so let's remove education that can help them have better lives because some of the struggling kids are black . Counterintuitive, oversensitive, and d…

> because some of the struggling kids are black What about the black overachievers? Princeton certainly didn't lower the bar for him [0] [0] https://www.cnn.com/2020/05/10/us/princeton-first-black-vale...

That's super cool, good for him. It's also an anecdotal example and relatively meaningless in the scheme of things.

I'm not even saying that black kids have any inherent disadvantages, but that people have become so sensitive to that perception as to seriously hinder actual education.

Seriously, people are worried about racial sensitivity in math. These two things do not go together, should not go together, and have almost zero reason to interact.

Re: SpaceX installed 29 Raptor engines on a Super Heavy rocket last night

#380

Post by Ajedi32 »

mlindner wrote: post #182
Ajedi32 wrote: post #58

Earlier quoted context omitted.

Wow, no kidding. The gold Merlin would be a quarter of the price![1][2][3] (At least in terms of materials.) [1]: https://arstechnica.com/science/2020/05/nasa-will-pay-a-stag... [2]: https://www.google.com/search?q=merlin+engine+dry+mass [3]: https://www.wolframalpha.com/input/?i=%28630+kg+of+gold+in+U...

Keep in mind gold is a lot denser, so it'd be a miniature engine if you made it out of pure gold. If you take the volumetric space of all the materials that might lead to a different answer, but that's hard to do. (I guess you could make it out of gold foam.)

Probably closer to half the price of the RS-25 then, assuming normal Merlins are made mostly out of steel:

https://www.wolframalpha.com/input/?i=%28%28%28630+kg+*+%28d...

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