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SpaceX test flight of Starship SN-5 [video]

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Re: SpaceX test flight of Starship SN-5 [video]

#341

Post by menybuvico »

pfdietz wrote: post #288
throwaway0a5e wrote: post #224

Earlier quoted context omitted.

Africa was in Europe's back yard yet when they got the opportunity they colonized the Americas. Colonizing a formerly unexplored place where nobody has yet laid claim has a lot of appeal (and this time we (probably) don't have to kill/displace the natives to do it).

Europeans were kept out of Africa by disease.

I always heard it was a logistic issue more than anything else? Getting from Europe to the Americas and then back in a sailing vessel is easier than getting to Africa's East coast and back.

Re: SpaceX test flight of Starship SN-5 [video]

#342

Post by menybuvico »

nubero wrote: post #120
sabujp wrote: post #114

Earlier quoted context omitted.

Future of space as presented in shows like the Expanse. controlled by trillionaires and their companies and powerful people in governments all killing each other over space rocks. We're a long way from Star Trek, that's going to take a more fundamental advance not at all related to technology.

I’m glad that not everyone in human history has shared your bright outlook, otherwise we would still live in caves…

I'd prefer corporate warfare in the Asteroid belt over international conflicts in Earth.

Regardless, unless we manage to come up with a new system that actually works, chances are that commercialization of space is one of the few ways for us to establish a presence off this planet.

Re: SpaceX test flight of Starship SN-5 [video]

#343

Post by krisoft »

jvanderbot wrote: post #311
sandworm101 wrote: post #245

Earlier quoted context omitted.

>> - in-orbit refueling. Starship is big and heavy and basically can't get anywhere unless it's re-fueled in orbit. This is one of those "let's see" things that SpaceX has talked about but never actually explained. Their current rocket tech offers no hint as to how this is might happen. They aren't running internal bladders in their tanks. So the physical act of moving fuel from one tank to another is an open questio…

Transfer tanks, not fuel. In-orbit servicing using robots, please. or just dock the tanks as vehicles.

Sounds like a good idea. The problem is that for weight efficiency reasons in modern rockets the tank is the rocket. (So much so that they often crumble if you are not providing sufficient internal pressure.)

Re: SpaceX test flight of Starship SN-5 [video]

#344

Post by menybuvico »

nfoz wrote: post #182
sekai wrote: post #174

Earlier quoted context omitted.

Let's look at this way, humanity needs to become multiplanetary species to prevent extinction if some sort of cataclysm happens on Earth: nuclear war; Yellowstone erupts, etc. Compared to that, any other problem seems insignificant.

This will sound weird, but I have no idea why anyone cares about the abstract "survival of human species". I care very deeply about the lives of people actually living here right now. But if Earth is wiped out, what does it matter that some humans are alive somewhere? Except of course that I'm glad for them that they didn't get killed. But we're talking about generations from now anyway, and there are more direct way…

There is the more generic idea of leaving a track in history, making sure one's offspring survives. If one of my descendants make it off-planet and thrives there once the Zombies attack/the meteor strikes/the nukes go off then my line will continue. I have no logic explanation for wanting to continue my bloodline, but I guess it's just a natural instinct.

The second reason to get off-world is the more far-fetched one, but assuming we can establish that other worlds are dead or sterile then we are free to customize it as we please without having to feel bad about it. In the long run we could leave Earth completely, allowing whomever comes next to develop freely without our intervention.

Re: SpaceX test flight of Starship SN-5 [video]

#345

Post by menybuvico »

hnrq wrote: post #201
sekai wrote: post #174

Earlier quoted context omitted.

Let's look at this way, humanity needs to become multiplanetary species to prevent extinction if some sort of cataclysm happens on Earth: nuclear war; Yellowstone erupts, etc. Compared to that, any other problem seems insignificant.

I hate this argument. There is no foreseeable disaster that would make Earth less habitable than any other solar system body. Even if every nuke we have was detonated, it would still be orders of magnitude easier to survive on what remains of Earth than to live in Mars. I'm not saying there are no existential risks at all, but being on other planets would not make us any more likely to survive to them than to simply…

Well, there is the question of whether we will ever have the possibility of developing this technology again.

I see no immediate risks to life on Earth, and considering we're quite hard to get rid of, I suspect the human race will be here for quite some time yet. The ability to do a large-scale settlement on other planetary bodies on the other hand, might go away considerably sooner, and who knows if/when we will be able to do it again if we ever end up in a situation where it might be needed.

Regardless, there are other reasons, as you say. For one, space-based manufacturing would allow us to increase the standard of living on Earth without having to worry about things like CO2 levels and pollution. If we start commercializing space then I expect colonization to follow as a natural result of that and we won't have to worry about the more philosophical side.

Re: SpaceX test flight of Starship SN-5 [video]

#346

Post by sobani »

credit_guy wrote: post #250
joakleaf wrote: post #132

Earlier quoted context omitted.

Indeed these numbers are impressive, but can it even be done? Is it even possible both in terms of climate change/overall environmental impact, and in terms of how much methane (fuel) we actually have. Elon Musk's vision is getting 1 million people to Mars (if I remember correctly) within this century. 100 per starship will require 10000 launches. Distributed over 70 years, that's about 1300 Martian voyages per year.…

Emissions calculation for Starship: - each starship burns 4600 tons of methalox fuel - the mixture ratio of the propellent is 78% O2 and 22% CH4 [1] - that means that each 100 tons of methalox results in 53.6 tons of CO2 and 2.5 tons of CH4 - generally in the climate science it is accepted that one ton of CH4 is equivalent to 25 tons of CO2 - overall, each 100 tons of propellent will produce 116 tons of CO2-equivalen…

> the propellent is O2 and CH4 [1]

> that results in CO2 and CH4

The chemical reaction of O2 + CH4 -> CO2 + CH4 does not compute.

More likely is the reaction 2 O2 + CH4 -> CO2 + 2 H2O.

So no methane emissions, that's the actual fuel. Only CO2 (and water) emissions.

Re: SpaceX test flight of Starship SN-5 [video]

#347

Post by koalala »

nfoz wrote: post #182
sekai wrote: post #174

Earlier quoted context omitted.

Let's look at this way, humanity needs to become multiplanetary species to prevent extinction if some sort of cataclysm happens on Earth: nuclear war; Yellowstone erupts, etc. Compared to that, any other problem seems insignificant.

This will sound weird, but I have no idea why anyone cares about the abstract "survival of human species". I care very deeply about the lives of people actually living here right now. But if Earth is wiped out, what does it matter that some humans are alive somewhere? Except of course that I'm glad for them that they didn't get killed. But we're talking about generations from now anyway, and there are more direct way…

Because we are all genetically related, and humans, like most or all organisms, care about their genetic code surviving.

Re: SpaceX test flight of Starship SN-5 [video]

#348

Post by pharke »

hnrq wrote: post #201
sekai wrote: post #174

Earlier quoted context omitted.

Let's look at this way, humanity needs to become multiplanetary species to prevent extinction if some sort of cataclysm happens on Earth: nuclear war; Yellowstone erupts, etc. Compared to that, any other problem seems insignificant.

I hate this argument. There is no foreseeable disaster that would make Earth less habitable than any other solar system body. Even if every nuke we have was detonated, it would still be orders of magnitude easier to survive on what remains of Earth than to live in Mars. I'm not saying there are no existential risks at all, but being on other planets would not make us any more likely to survive to them than to simply…

It's not a matter of Earth becoming uninhabitable. You're right that it would take a lot to do that, though it is possible with a large enough asteroid or some unexpectedly fast acting runaway greenhouse effect. The problem is of human civilization continuing at its current level and continuing to advance. Any number of small disasters could set us back hundreds if not thousands of years. We have direct evidence and record of this happening multiple times throughout human history so we know it can and probably will happen. That's why we need a self-sustaining society elsewhere, preferably far enough away to resist whatever disaster causes Earth to fall.

Re: SpaceX test flight of Starship SN-5 [video]

#349

Post by ben_w »

nickik wrote: post #312
ben_w wrote: post #160

Earlier quoted context omitted.

Although I’m also not expecting 1 million people on Mars in my lifetime, I think you’re assuming SpaceX never gets close to the Musk price goals. You might be right to do that — I’m no rocket scientist — but the target price would get a million people there for $200 billion, not your $5 quadrillion. Yes, I also expect the first few thousand to be in easily damaged domes. I also expect them to bring some of The Boring…

How are tunnels pointless in a future of self driving cars, the opposite is true, tunnels make even more sense when cars drive themselves.

Self driving cars done right will be able to do full speed while literally, not metaphorically, touching bumpers.

Traffic jams with human drivers happen spontaneously when the cars get close enough that overcompensation turns into a negative spiral.

Re: SpaceX test flight of Starship SN-5 [video]

#350

Post by FrojoS »

napier wrote: post #247
martythemaniak wrote: post #205

I really love the out-in-the-open development process. It doesn't cost SpaceX anything, yet they attract lots of internet media where people set up streams, discuss progress etc. The next year should be pretty exciting as they develop things further. Starship has a number of big innovations, which are: - the raptor engine. This was developed behind closed doors and is sort of finished. We won't see much of it, but it…

> any upcoming engine that can compete with it. There's the criminally underfunded SABRE engine, an a air-hydrogen mix breathing-rocket hybrid design from Reaction Engines that rated to reach speeds of Mach 25 (roughly 35,000 miles per hour). As modelled, it's more efficient than any other current or proposed chemical propulsion technology, and the proposed single-stage runway launchable system would be capable of de…

Apart from the other reasons pointed out by others:

Single stage to orbit is sexy, but multiple stage to orbit is inherently more efficient and I see no reason why it Would be more expensive if you reuse all stages.

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