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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]

#321

Post by pjkundert »

jacquesm wrote: post #149
llboston wrote: post #43

Earlier quoted context omitted.

Another significant thing is that Starship is designed to be mass manufactured at a relatively low cost. SpaceX can crank out thousands of Starships, fly them to Mars and build a million people colony. Starship is truly a game changer!

You write that as if it is a done deal. Mars' atmosphere is roughly .5% of that of Earth and almost exclusively CO2. Temperature ranges are well out of what they are on Earth. It is hard for technology to survive there, it is impossible for people to survive there until there has been an unbelievable investment in infrastructure. If you think there will be a million people colony on Mars in your lifetime than you are…

TBM FTW.

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

#322

Post by ncmncm »

bconnorwhite wrote: post #255
ncmncm wrote: post #158

Earlier quoted context omitted.

To get a sense of the difficulty, imagine sending a million people to the South Pole to set up a self-sustaining colony. That would be much more than 1000 times easier than establishing such a base on Mars.

True, but I'm not sure difficulty is as relevant if the motivation is there. You can't terraform the South Pole. Mars reopens the frontier whereas the South Pole is a dead end

The South Pole starts out way more terraformed than Mars can ever be. It has air, water, gravity, and is warmer. You can just put up domes and it's already way better than Mars. Mineral wealth is only a mile down, under the ice.

Under the sea starts out way more terraformed than Mars can ever be. It has water, gravity, and is warmer. Mineral wealth is right at hand.

The cloud tops of Venus start out way more terraformed than Mars can ever be. It has air pressure, gravity, water, carbon, sulfur, and shirtsleeve temperature.

What motivation does Mars provide that those don't?

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

#323

Post by h0l0cube »

shdh wrote: post #295
h0l0cube wrote: post #180

Earlier quoted context omitted.

Life will go on in other parts of the universe, and all life, no matter where they locate themselves, will have some kind of existential threat. And it doesn't matter how many Dyson spheres are made, if humans aren't dedicated to improving the collective opportunity to live life without suffering, there's little real 'significance' to extending the project of humanity compared to any other life-form.

> improving the collective opportunity to live life without suffering You cannot eliminate suffering. > Life will go on in other parts of the universe, and all life, no matter where they locate themselves, will have some kind of existential threat. There's no guarantee or evidence that there is sentient life in the universe

> You cannot eliminate suffering.

!= improving the collective opportunity to live life without suffering

> There's no guarantee or evidence that there is sentient life in the universe

https://news.ycombinator.com/item?id=24067017

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

#324

Post by HPsquared »

SEJeff wrote: post #304
jcun4128 wrote: post #275

Earlier quoted context omitted.

Yeah looks like 3 for 3 so far. It seems like a big number... as opposed to just 5 (Saturn V). What is the rationale for more smaller engines(other than offset/greater forces/new R&D)?

Why only turn it up to 11 when you can turn it up to 31? See the Starship dial goes all the way to 31.

Things have different scaling laws. Very large rocket engines might not be practical for a range of reasons: wall thickness required to contain the high pressures (this is probably a big one) combined with the temperatures, combustion instability, controllability, and general ability to manufacture. Why are elephants and ants differently shaped? Another example is piston engines: large ones generally have lots of (relatively small compared to the overall displacement) cylinders rather than a couple of massive ones.

If a small number of rocket engines was required they would probably have a completely different design, perhaps an aerospike. Or maybe resurrecting Project Orion?

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

#325

Post by h0l0cube »

bbojan wrote: post #318
h0l0cube wrote: post #180

Earlier quoted context omitted.

Life will go on in other parts of the universe, and all life, no matter where they locate themselves, will have some kind of existential threat. And it doesn't matter how many Dyson spheres are made, if humans aren't dedicated to improving the collective opportunity to live life without suffering, there's little real 'significance' to extending the project of humanity compared to any other life-form.

How do you know there is life in other parts of the universe? Do you at least consider a possibility that life originated only once?

Let's say by chance we discover an oracle, that could reveal with perfect certainty whether life existed anywhere else in the universe. I wager, that if I made some non-trivial wager with any other reasonable (and educated) person holding this contrarian view, they would back down before the oracle revealed its answer.

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

#326

Post by maxioatic »

nine_k wrote: post #280
maxioatic wrote: post #91

Earlier quoted context omitted.

I feel the same way. Likely not to start but over time I think they would build up capability. I wonder how lesser gravity on Mars would help/hurt their efforts. Easier to heft heavy gear up high? I'm also thinking on the flip side, say a Starship somehow gets irreparably damaged getting to Mars (but successfully gets there). With some basic gear they should be able to part it out and re-use the steel. Like for a new…

The idea of using parts of the landing unit for materials to build local structures and machines is not new. Probably, with proper planning and construction of the lander unit parts, it can be facilitated. But you have to plan for another mission to pick up the crew, unless you're on the Moon where you could use an electromagnetic catapult to achieve orbit, and then slowly ascend to the rocket that would take you hom…

I didn't know that. Sure, it doesn't sound like a revolutionary idea, and I'm not surprised at all its been thought of. I was basing it on the assumption there are people there already who aren't leaving. With a colony on Mars/Moon it surely becomes more useful to have a vast amount of steel to reuse than some crazy alloy.

Electromagnetic catapult, huh. Sounds fun as hell.

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

#327

Post by Yetanfou »

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…

SABRE might be an option for a first stage on vertically launched vehicle, to be used in that part of the atmosphere where the engine can get most - or even all - of its oxygen from the air.

Then again, if that stage were to be limited to a maximum height of ~20km it might as well be equipped with a stack of upgraded J58 engines (as uses in the SR-71), saving the weight of the cryogenic coolers used to produce LOX for those rocket engines. I guess SABRE makes more sense for a space plane than it does for a vertically launched rocket.

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

#328

Post by 0xffff2 »

cosmotron wrote: post #315
0xffff2 wrote: post #306

Earlier quoted context omitted.

I find it completely baffling that it's your dream to work for SpaceX but you're unwilling to relocate? I'm stuck in the bay area (which I absolutely despise) because of my job, but I get to write flight software for spacecraft so I deal with it.

0xffff2, you yourself just said, "I'm stuck in because of ." It can't be that baffling to think that h3rsko is also stuck (e.g. because of a family).

Yes, that's because I was using the word "stuck" metaphorically. I choose to be stuck because I actually find the benefits of being stuck to outweigh the costs. If I lost my job it probably wouldn't take me 24 hours to pack my shit and be gone. But as long as I'm here getting to do what I want to do I stay.

If you can't figure out how to move to a different state to pursue a dream, it's not much of a dream.

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

#329

Post by jcun4128 »

HPsquared wrote: post #324
SEJeff wrote: post #304

Earlier quoted context omitted.

Why only turn it up to 11 when you can turn it up to 31? See the Starship dial goes all the way to 31.

Things have different scaling laws. Very large rocket engines might not be practical for a range of reasons: wall thickness required to contain the high pressures (this is probably a big one) combined with the temperatures, combustion instability, controllability, and general ability to manufacture. Why are elephants and ants differently shaped? Another example is piston engines: large ones generally have lots of (re…

I never quite got the Orion(nuclear?) engine design eg. is it literal "nuclear explosions" or just using nuclear as a heat source.

I think they push fluid through the bells, maybe other materials(like ceramic) for the larger nozzles... can they use magnetic field to contain heat... probably not assumes it's ionized or something ha... heat still goes through magnetism. I got it, active heat destructive interface ha.

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

#330

Post by stallmanite »

reddog wrote: post #191
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.

If there was a full scale nuclear war. And then the next week the Yellowstone super volcano erupted. And then the week after that an asteroid as big as the one that killed the dinosaurs hit Eurasia, earth would still be wildly more habitable that Mars.

And after a collision like the one that created the moon? How habitable during a gamma ray burst?
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