SpaceX Is Now One of the World’s Most Valuable Privately Held Companies • Hacker News Board

Re: SpaceX Is Now One of the World’s Most Valuable Privately Held Companies

#301

Post by angstrom » Sat, Jul 29, 2017, 5:53 PM UTC

trevyn wrote: post #225

EGreg wrote: post #218

Earlier quoted context omitted.

Can you elaborate on this? Are you saying with a 10% higher gravity we wouldn't be able to escape Earth's field with any amount of thrust? What?

Possibly not able to carry enough chemical fuel to lift the fuel into space and return and do a controlled landing without refueling? That seems more plausible. Fuel is heavy, and most of it is spent on... lifting fuel.

Yes, this is what I was referring to. Though there's probably another percentage that makes most rocket fuel also insufficient for anything more than LEO.

Re: SpaceX Is Now One of the World’s Most Valuable Privately Held Companies

#302

Post by simonh » Sun, Jul 30, 2017, 12:39 PM UTC

sidlls wrote: post #269

simonh wrote: post #260

Earlier quoted context omitted.

You are quite right that the space launch industry and the technology it uses wouldn't exist without government research and funding. That's perfectly true. But it's also true that without Musk there would currently be no prospect of significant rocket component reuse for another generation. Rocket launch costs would be double or triple what they currently are. It also seems very likely now that within my lifetime we…

I'd argue that Musk, using the facade of "Private Market Hero", has made government spending on research in this area palatable enough (again) to make progress. Sure, he's a key personality , but it's not like he's accomplishing these things outside of the context of being heavily funded and guided by the government.

So what? Do none of the achievements of the engineers that drove the US space programme through the last century 'count' because they were government funded? What a bizarre world view.

As it happens none of the re-usability programme (Grasshopper, the drone ships, etc) was actually funded by the government. That came from around a billion dollars of private capital investment. Musk talked about this in a TED talk.

Re: SpaceX Is Now One of the World’s Most Valuable Privately Held Companies

#303

Post by kabouseng » Tue, Aug 01, 2017, 8:01 AM UTC

EGreg wrote: post #263

trevyn wrote: post #225

Earlier quoted context omitted.

Possibly not able to carry enough chemical fuel to lift the fuel into space and return and do a controlled landing without refueling? That seems more plausible. Fuel is heavy, and most of it is spent on... lifting fuel.

But the way the rocket works is creating a continuous explosion behind it. The propellant explodes, pushing the rocket. It's not just the rocket equation, but the explosion from a central point BEHIND the rocket that pushes it further. Having a nuclear explosion for example behind the rocket would surely be enough to push it into space... even on Jupiter.

"But the way the rocket works is creating a continuous explosion behind it."

Not quite, it's all about mass flow.