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SpaceX to Send Privately Crewed Dragon Spacecraft Beyond the Moon Next Year

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Re: SpaceX to Send Privately Crewed Dragon Spacecraft Beyond the Moon Next Year

#171

Post by morsch »

DennisP wrote: post #146
lftl wrote: post #128

Earlier quoted context omitted.

As an interesting bit of trivia: the most prevalent greenhouse gas in the atmosphere? Water vapor.

Which doesn't mean that emitting water vapor from a rocket adds to global warming. It just adds to the rain.

True as long as you intend to fly your rocket within the troposphere, the lower ~10 miles of the atmosphere. Above that, water vapor seems to stick around a long time and is currently understood to be quite harmful[1]. This is also an issue with high-flying planes (not that flying low is better, due to the decreased efficiency). However, more research is needed[2].

[1] http://www.grida.no/publications/other/ipcc_sr/?src=/climate... (kind of old, but I think the more recent IPCC reports are in a similar vein)

[2] https://eos.org/research-spotlights/the-forgotten-water-vapo...

Re: SpaceX to Send Privately Crewed Dragon Spacecraft Beyond the Moon Next Year

#172

Post by ogezi »

I wonder who the people going on this trip are. Are they billionaires, a rich couple planning a honeymoon. You'd have to be rich to do this right? I also wonder which kind of insurance both Spacex and the individuals have for this.

It's amazing that private companies are now doing things that were previously only one by governments and nations.

I don't know how this will work out but congratulations to Musk, Spacex and NASA.

Re: SpaceX to Send Privately Crewed Dragon Spacecraft Beyond the Moon Next Year

#173

Post by briandear »

Mithaldu wrote: post #162
paulddraper wrote: post #158

Earlier quoted context omitted.

> I also think that spending money on a roundtrip to the moon is way better for humanity than spending it on champagne, caviar and cars. How? I'm not saying you're wrong, but gut instinct is that automobiles are more useful to humans. I'd like to hear your thought process.

Fair question. In short: Unless you're buying Tesla your car expenditures won't fund any significant research into improving cars in a way that benefits humankind.

[citation needed]

Re: SpaceX to Send Privately Crewed Dragon Spacecraft Beyond the Moon Next Year

#174

Post by Udik »

nickik wrote: post #142
Udik wrote: post #87

Earlier quoted context omitted.

I agree, there is no fundamental problem. But that couple of delays will bring the actual date much further away than "late next year". I'm sure Elon Musk is capable of great things, it's just that he's very obviously squeezing the people in his companies to the limits and beyond, by publicly announcing objectives that are just about possible, provided that his employees will work day and night for entire years.

I simply don't understand why people are always up in arms about his companies being so bad with their employees. Lots of companies push people to do more ours. God knows, I have worked insane hours for far worse reasons. Plus the actual evidence for Elons companies being far worse then anybody else is not really there. Plus, its not like all those educated people that work at SpaceX would live in the gutter if they…

That's a completely different matter, I just meant to say that Elon Musk's estimates are often extremely optimistic.

You know (if you're a developer) when you're working on a very exciting piece of code that will do wonderful stuff, and you have clear in your head what you're doing and how to do it, and think "it'll take me an hour, can't wait to see it working" and then at 4 AM you're still there, always in the same state of mind, with half of your brain asleep and the other half still perfectly focused on the result? Yep, I think that's Elon Musk. Still in the splendour of his early twenties :)

Re: SpaceX to Send Privately Crewed Dragon Spacecraft Beyond the Moon Next Year

#175

Post by briandear »

ogezi wrote: post #172

I wonder who the people going on this trip are. Are they billionaires, a rich couple planning a honeymoon. You'd have to be rich to do this right? I also wonder which kind of insurance both Spacex and the individuals have for this. It's amazing that private companies are now doing things that were previously only one by governments and nations. I don't know how this will work out but congratulations to Musk, Spacex a…

That's really stretching the definition of private company considering NASA is the major provider of both funding and infrastructure.

Re: SpaceX to Send Privately Crewed Dragon Spacecraft Beyond the Moon Next Year

#176

Post by M_Grey »

godelski wrote: post #163
M_Grey wrote: post #151

Earlier quoted context omitted.

Probably they should. https://news.ycombinator.com/item?id=13745315

Well there's a huge difference when talking about radiation exposures going to the moon and Mars. For one you don't expect a solar event to happen, you really hope one doesn't, when going to the moon. Going to Mars you expect a few. With cosmic radiation we're talking about the difference between a few days and a year. Plus you have to have pretty good shielding when crossing the Van Allen belts. You can consider the…

I'm less worried about this mission, and more than it's going to give people an (increasingly) false confidence that we're ready for Mars.

Re: SpaceX to Send Privately Crewed Dragon Spacecraft Beyond the Moon Next Year

#177

Post by pklausler »

gydfi wrote: post #78

Just looking up records: the furthest anyone has ever been from Earth is Apollo 13 who passed 158 miles above the lunar surface. I imagine that would be a pretty easy record to break, if you're doing a translunar flight anyway then getting a bit higher doesn't take much more energy (source: played a lot of Kerbal). On the other hand the passengers might prefer a close-up view of the Moon to a record.

But the moon isn't at a fixed distance. It's possible that one of the other cislunar or landing Apollo missions was more distant, geocentrically, even with their standard 69-mile lunar orbital heights.

Re: SpaceX to Send Privately Crewed Dragon Spacecraft Beyond the Moon Next Year

#178

Post by BWStearns »

gravypod wrote: post #121
beojan wrote: post #82

Earlier quoted context omitted.

There's gravity and a rock on Earth too. Just going up into orbit, then landing back on Earth, is a much better way of testing a Mars landing.

The Earth has a full atmosphere with winds, an expansive array of magnetic and electric fields, and a much much higher gravitational pull then Mars or the moon. About a factor of 10 removed from mars and about a further factor of 10 removed from the moon. You'd obviously need more fuel, and fuel that can burn in a completely different atmosphere then it's intended to run in. It's an invalid test for the kind of usefu…

I wonder if there's an altitude you could do a "landing" at that would be thin enough atmosphere and weak enough gravity to get close to Martian conditions.

Re: SpaceX to Send Privately Crewed Dragon Spacecraft Beyond the Moon Next Year

#179

Post by DennisP »

morsch wrote: post #171
DennisP wrote: post #146

Earlier quoted context omitted.

Which doesn't mean that emitting water vapor from a rocket adds to global warming. It just adds to the rain.

True as long as you intend to fly your rocket within the troposphere, the lower ~10 miles of the atmosphere. Above that, water vapor seems to stick around a long time and is currently understood to be quite harmful[1]. This is also an issue with high-flying planes (not that flying low is better, due to the decreased efficiency). However, more research is needed[2]. [1] http://www.grida.no/publications/other/ipcc_sr/?…

Wow, learn something new every day. Thanks!

Re: SpaceX to Send Privately Crewed Dragon Spacecraft Beyond the Moon Next Year

#180

Post by coryfklein »

morsch wrote: post #148
jfoutz wrote: post #102

Earlier quoted context omitted.

Isn't the exhaust just water?!?

Doesn't really matter what it exhausts, it expends energy either way. If it ran on hydrogen, you'd probably have to use electrical energy to produce that. Even if you somehow got the hydrogen "for free", there are other things you could use it for. This is all quite separate from the moral issue, to which I have nothing to add.

> Doesn't really matter what it exhausts, it expends energy either way.

Energy usage is not the only consideration, and it certainly does matter what it exhausts. Exhausting an inert gas is definitely preferable to a greenhouse gas, which would be preferable to exhausting anthrax, etc.

The composition of the exhaust is going to affect the positivity of the public reaction to a billionaire burning it into public air space for leisure.

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