SpaceX test flight of Starship SN-5 [video] • Hacker News Board

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

#291

Post by jcun4128 » Wed, Aug 05, 2020, 7:17 PM UTC

nine_k wrote: post #289

jcun4128 wrote: post #277

Earlier quoted context omitted.

The Raptor engines are more advanced than those NK-31's right? I mean by newer manufacturing but I remember seeing something about these Russian engines that were closed off in some factory somewhere/later(years) found and they were supposedly still more advanced/powerful(efficient?) than modern rockets.

You likely meant his engine: https://en.wikipedia.org/wiki/RD-180 It wasn't used in the Soviet lunar program; these are remnants of the Soviet Space Shuttle-like program (specifically the Energia rocket that lifted the Buran space plane).

yeah that's possible those are the ones, I just remember seeing some documentary about finding these Russian rocket engines that were hidden away to protect them from being destroyed I think

edit: oh it's NK33/RD180 [0]

[0] https://www.youtube.com/watch?v=TMbl_ofF3AM

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

#292

Post by shdh » Wed, Aug 05, 2020, 7:38 PM UTC

Ajedi32 wrote: post #268

mabbo wrote: post #249

Earlier quoted context omitted.

> Not sure why SpaceX haven't invested in it yet > an a air-hydrogen mix breathing-rocket hybrid design Tough to use a breathing rocket anywhere but Earth. And SpaceX's goal is to use this to land on the Moon, Mars, everywhere.

That's true for Starship (the second stage) but AFAIK Super Heavy (the first stage) will only ever be used on Earth. Seems like an air-breathing rocket engine could potentially be good for that use-case.

Then you have to introduce another system (SABRE) and integrate it with your system instead of just using the same Raptor engines being used in the second stage vehicle.

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

#293

Post by shdh » Wed, Aug 05, 2020, 7:40 PM UTC

nkoren wrote: post #273

jcun4128 wrote: post #252

Earlier quoted context omitted.

> 31 raptor engines That'll be something to see haha N1

The Falcon Heavy uses 27 engines and has a perfect track record ,so they've got some credibility here.

Just to add clarification, Falcon Heavy uses the Merlin engine, not the Raptor engine.

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

#294

Post by ba2plus » Wed, Aug 05, 2020, 7:44 PM UTC

paulsutter wrote: post #227

dgritsko wrote: post #208

Earlier quoted context omitted.

> the most advanced rocket engine ever made Would love to learn more about this, can you expand? What makes Raptor so unique?

In addition to being full-flow, Raptor runs on methane (CH4, the simplest hydrocarbon), which already exists many places in the solar system (including Mars), and is easier to manufacture than kerosene or liquid hydrogen. SpaceX developed an incredibly advanced simulator to make it happen: https://www.youtube.com/watch?v=vYA0f6R5KAI

Mars could be the key to opening up the entire solar system. It's close enough to the sun for solar power to be practical, it's proven to have the mass amounts of subsurface ice and atmospheric CO2 needed for Sabatier-process methane/oxygen production, and it has a very shallow gravity well that would make it easy to lift huge propellant loads into orbit.

I don't think it's a stretch to imagine that Mars-based tankers supplying propellants and breathing oxygen would be commonplace through the solar system by the end of the century.

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

#295

Post by shdh » Wed, Aug 05, 2020, 7:55 PM UTC

h0l0cube wrote: post #180

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.

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

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

#296

Post by [deleted] » Wed, Aug 05, 2020, 7:58 PM UTC

dmurray wrote: post #146

adventured wrote: post #111

Earlier quoted context omitted.

Google at least is a bad option. You won't actually get any value representation, any exposure, due to their extreme market cap. Most likely close to 0% of the SpaceX ownership stake is represented in Google's stock. Let's assume though for the sake of argument that some large part is, say $1.3 billion of the stake is represented (3% of $44 billion). That's equal to about 1.3% of Google's market cap (~$1t). Whatever…

I don't get the Berkshire Hathaway analogy. If you buy that stock, in what way are you not getting "1-to-1 direct exposure to the Berkshire portfolio"? You're owning the same investments Warren Buffet owns, in the same proportions, to within a rounding error. It would be a mistake to invest in BH because, say, you're really bullish on Dairy Queen, but that doesn't seem like the mistake you're describing.

[deleted]

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

#297

Post by ba2plus » Wed, Aug 05, 2020, 7:59 PM UTC

buzzwordninja wrote: post #220

hugs wrote: post #200

Earlier quoted context omitted.

A science outpost, specifically as a place to put telescopes, seems the most compelling. The rest of the population would then grow along side the science outpost to service it (food, transportation, etc.) A looong time until a million people, though.

Why would you put a telescope in a gravity well though? Would it not be easier to build large structures in orbit or at one of the Lagrange points?

There's been some really interesting ideas for a new generation of telescopes that Starship's cargo capacity could enable. Telescopes on the far side of the moon are the classic example. They'd be shielded from the sun for 14 days out of 28, permanently shielded from Earth, and still have all the advantages of being in a vacuum. Gravitational-wave telescopes on the geologically-stable lunar surface are another interesting idea.

But I think my favourite idea is infrared scopes in the polar craters, some of the coldest places in the solar system. You don't need a complicated JWST-style extendable sun shield or limited helium supply. You are limited in terms of direction, but that's not a bad tradeoff.

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

#298

Post by shdh » Wed, Aug 05, 2020, 8:00 PM UTC

bconnorwhite wrote: post #261

Diggsey wrote: post #25

What you don't get a sense for in the video is the size of this thing... It's absolutely bonkers. 9m (30 ft) in diameter 50m (160 ft) in height (or would be with the nose-cone) That's the height of a 12-story building. And this is the upper stage of the full rocket.

The crazy part is that Elon has said this will look like a rowboat compared to their future rockets

Could you share a source for this quote?

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

#299

Post by jbay808 » Wed, Aug 05, 2020, 8:01 PM UTC

adventured wrote: post #111

dodobirdlord wrote: post #107

Earlier quoted context omitted.

It seems you could buy a stake in a number of publicly traded companies and funds that themselves own a stake. Seems like Google and Fidelity each own about 4% of SpaceX, maybe Fidelity is offering it as a component of some fund? https://en.wikipedia.org/wiki/SpaceX#Ownership,_funding_and_...

Google at least is a bad option. You won't actually get any value representation, any exposure, due to their extreme market cap. Most likely close to 0% of the SpaceX ownership stake is represented in Google's stock. Let's assume though for the sake of argument that some large part is, say $1.3 billion of the stake is represented (3% of $44 billion). That's equal to about 1.3% of Google's market cap (~$1t). Whatever…

Math check -- I think Google's SpaceX ownership stake would be closer to 0.13% of Google's value, not 1.3%. Is that what you meant?

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

#300

Post by ba2plus » Wed, Aug 05, 2020, 8:01 PM UTC

laichzeit0 wrote: post #269

zamalek wrote: post #258

Earlier quoted context omitted.

> mass manufactured at a relatively low cost. ... which also explains Tesla, mass production of Earth-faring machines is one way to prepare for mass production of space-faring machines (and battery tech is going to be important for living in space). When you look at Musk's ventures, they really all end at Mars.

The Boring company. Develop tech to drill deep tunnels on Mars? Electric cars and batteries cause you will need that on Mars? Even the Cybertruck looks like something destined for Mars.

And a Starlink network would mean an instant global Martian internet.