SpaceX successfully launches two humans into orbit • Hacker News Board

Re: SpaceX successfully launches two humans into orbit

#751

Post by tornato7 » Sun, May 31, 2020, 6:06 PM UTC

LargoLasskhyfv wrote: post #722

gruturo wrote: post #701

Earlier quoted context omitted.

High frequency traders do NOT want to be limited by the speed of light in a fiber - due to its refractive index (1.5 for ZBLAN according to Wikipedia) this is only 66% of the speed of a radio signal. Over 10km this amounts to an 11 microseconds difference - already significant for HFT. This is why they have been leveling hills to carve a (mostly, with minimal amount of repeater towers) line of sight path between NYC…

One could use hollow core fiber, which has much higher limits. Up to 99% of light in a vacuum IIRC.

A wave guide?

Re: SpaceX successfully launches two humans into orbit

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Post by giantrobot » Sun, May 31, 2020, 6:18 PM UTC

yellowapple wrote: post #728

giantrobot wrote: post #704

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Most asteroids are worthless chunks or carbon, another significant portion are sort of dirty balls of sand and rock. The smallest portion are composed of any metals. Metallic asteroids are mostly iron and nickel and unlikely to be loaded up with precious metals. Any that would be interesting for mining would be in the asteroid belt which requires significant amounts of energy to reach in a reasonable time frame. You…

> Ceres does not currently have a space gas station on the surface. Golly gee whittakers, really? I had no idea! Well that changes everything! Obviously we'll need to build infrastructure. My point is that it's a worthwhile investment. You obviously seem to disagree, which is fine, but if all you're going to do is be needlessly condescending then this conversation is probably not worth continuing (but eh, it's a Sund…

Your every response to very real engineering challenges is "just do the thing" or hand wave it away. I don't think you actually understand the difficulties. You have read some pop science books and some "hard sci-fi" and think you've got it all worked out.

Everything seems easy and straight forward when you don't understand the actual problems. Deep space is hostile and unforgiving. Asteroid and cometary landing/sample return probes have had a rough track record because despite a lot of great engineering and effort the task is extraordinarily difficult. You're talking about mining asteroids like it's a solved problem and it's just a question of willpower.

Be interested in spaceflight, manned or otherwise. It's awesome and there's tons to learn. It's great to explore. But if you're serious about the endeavor, don't pretend it's not immensely difficult. Many things in pop science books or science fiction are simply not practical and many more aren't even possible. Also while space is awesome, Earth is right here. It's the only place in the solar system humans can live without being wrapped in massive amounts of technology. There's much better odds of Civilization B being destroyed by a catastrophe than Civilization A here on Earth.

Re: SpaceX successfully launches two humans into orbit

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Post by dang » Sun, May 31, 2020, 6:21 PM UTC

jakswa wrote: post #540

dang wrote: post #231

Other things people have posted, whose threads we've merged hither: https://twitter.com/SpaceX/status/1266812530833240064 https://techcrunch.com/2020/05/30/spacex-makes-history-with-... https://arstechnica.com/science/2020/05/todays-the-day-weath... If there's a particularly good article, we can swap out the URL above. Edit: beefman suggested the nasa.gov page ( https://news.ycombinator.com/item?id=23364975 ), so we'…

livestream still relevant? Docking with ISS tomorrow morning? All the tests they are doing?

Sorry for impugning the freshness of the livestream.

Re: SpaceX successfully launches two humans into orbit

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Post by elcritch » Sun, May 31, 2020, 6:43 PM UTC

pharke wrote: post #734

elcritch wrote: post #682

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The magnetosphere bit is intriguing... I've never heard of a proposal to use superconductors to generate a miniature magnetosphere outside of earth's. Even for earth orbit it seems that'd be helpful way to reduce radiation exposure. Superconductors should be able to be cooled to operating temperature readily enough, meaning minimal power once charged. Spaceship hulls are aluminum and non-ferromagnrtic. Odd to never h…

This has already been proposed for shielding the entire planet Mars, see https://www.popularmechanics.com/space/moon-mars/a25493/magn... (2017). I'd love to see SpaceX take a crack at this, conceivably it would amount to launching a modified MRI into Mar's L1. It's actually within the launch capability of Falcon Heavy so it's something they could start working on now.

That's amazing! Even a few shipment of neodymium magnets could be sent. Then in a 1,000 years after the collapse of our civilization and emergence of a new technological civilization there'd be a Mars with much thicker atmosphere and potentially even liquid water.

Even for regular human asteroid mining it looks like an artificial magnetosphere would be possible: https://physicsworld.com/a/magnetic-shield-could-protect-spa...

It's still surprising to me that the notion isn't prevalent in sci-fi or even hard sci-fi. Though as you mention even a modified MRI could do the job.

Re: SpaceX successfully launches two humans into orbit

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Post by ineedasername » Sun, May 31, 2020, 6:43 PM UTC

dahfizz wrote: post #723

ineedasername wrote: post #454

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That's not because of NASA's poor work though, much of the cost bloat there was due to the legislation that dictated how those programs had to operate, like sole-sourcing components, requiring use of Space Shuttle components furthering vendor lock in, etc. It's not a testament to NASA's failings, its a testament to politicians' self-serving legislation.

Isn't this exactly the case for private space companies like spacex? Government agencies will always be strapped down with bureaucracy, and so be less efficient than private companies. I've never seen anyone claim that NASA is incompetent.

I would say it should lead to reform in the legislative process for these sorts of projects. This launch represents the triumph of private enterprise, yes, but there is a strategic need for the US to have such capabilities independently of the ups & downs of private industry.

Re: SpaceX successfully launches two humans into orbit

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Post by ineedasername » Sun, May 31, 2020, 6:46 PM UTC

rossdavidh wrote: post #515

ineedasername wrote: post #454

Earlier quoted context omitted.

That's not because of NASA's poor work though, much of the cost bloat there was due to the legislation that dictated how those programs had to operate, like sole-sourcing components, requiring use of Space Shuttle components furthering vendor lock in, etc. It's not a testament to NASA's failings, its a testament to politicians' self-serving legislation.

True that, but that would point to the need to do this outside of NASA.

I would say it should lead to reform in the legislative process for these sorts of projects. This launch represents the triumph of private enterprise, yes, but there is a strategic need for the US to have such capabilities independently of the ups & downs of private industry. So I would say it points to the need to have a blended approach. I would love, for example, for NASA to license the technology from SpaceX with a massive knowledge-transfer initiative to provide NASA the capabilities to do these launches itself.

I would love, for example, for NASA to license the technology from SpaceX with a massive knowledge-transfer initiative to provide NASA the capabilities to do these launches itself.

Re: SpaceX successfully launches two humans into orbit

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Post by acheron9383 » Sun, May 31, 2020, 6:52 PM UTC

borosT wrote: post #636

frakkingcylons wrote: post #152

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The sheer cost of launches is much lower on a Falcon 9 and Crew Dragon versus the Shuttle. Amortized per-launch cost for the Shuttle was about $1.5B [0]. The cost of the Demo-2 mission today with 2 astronauts costs $110M [1]. [0]: https://en.wikipedia.org/wiki/Space_Shuttle_program#Budget [1]: This article states the per-astronaut cost paid by NASA on a Crew Dragon mission is $55M, compared to $86M on Soyuz: https://…

does anyone know why it took so long for us to develop resuable rocket? Isn't reusable rocket the natural next step for space launching capabilities?

Propulsive landing is really hard, see the failure montage from Spacex as they iteratively worked on it. SpaceX also had a very strong incentive to develop the tech, since they are a commercial launch provider and could make more money. All the engineering was certainly not free, and the vehicle has to make some compromises in terms of lift capacity and such to make it work. Propulsive landing only looks easy now, but it is a supreme feat of engineering.

Re: SpaceX successfully launches two humans into orbit

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Post by mamon » Sun, May 31, 2020, 6:53 PM UTC

dleslie wrote: post #475

catalogia wrote: post #254

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I think the comparison between Elon Musk and Henry Ford starts to break down a bit towards the end of your comment. Elon Musk tweets plenty I don't like, but he's far from a Nazi.

This is definitely a hindsight is 20/20 moment. In an age where radio was new, where televisions were even newer, where transcontinental news took hours, days or even weeks to travel, the knowledge that the Nazis were engaging in mass murder was not readily available. When allied troops liberated the concentration camps they filmed everything that they saw because they were concerned that without footage no one would…

Reports about what's happening in concentration camps had been coming to Allied intelligence agencies since 1941 ([1]) but obviously they did not include any video footage, so they were hard to believe.

[1] https://en.wikipedia.org/wiki/Pilecki%27s_Report

Re: SpaceX successfully launches two humans into orbit

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Post by kortilla » Sun, May 31, 2020, 6:55 PM UTC

z3phyr wrote: post #578

kortilla wrote: post #298

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Not quite, it’s “If you build it, they might come.” You only need to look to the history of railroad in the US to see how infrastructure frequently didn’t pay off.

Railroads did pay off in most of the old world

Not for the initial investors/companies. That industry is fraught with booms and busts.

Re: SpaceX successfully launches two humans into orbit

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Post by stickfigure » Sun, May 31, 2020, 6:56 PM UTC

TeMPOraL wrote: post #665

Chathamization wrote: post #549

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Sure, as a society we do some things purely for emotional reasons. But we should be honest about that - we shouldn't pretend that the reason we're building the Washington monument is because of it's potential use as a grain silo. There's a lot more to exploration than space exploration (I think exploring something like the human brain will end up having a greater emotional and practical impact myself). But even if we…

Light lag is one reason for humans to go. Until we crack robotics and AI to the point science can do itself (which I doubt it'll happen in the next 30-50 years), we'll still need humans micromanaging the robots remotely, and it's much easier to do with HD video streams and with millisecond RTT when you're on a science ship orbiting the body in question, vs. using occasional photos that take hours to send, on top of 3…

which I doubt it'll happen in the next 30-50 years

I have to ask, why the rush? Why not wait 30-50 years until the robots are smart enough? Or we can bioengineer humans that are better adapted to that harsh environment?

This feels a bit like a real time strategy game, where someone at the start of the game wants to spend all their resources on big expensive research projects near the end of the tech tree. You're always better off building up the economy so you have enough surplus to tackle those expensive items later.