Elon Musk says he will put millions of people on Mars.

[GIThruster]

Can you say "O'Neill"?

Years ago I read that weightlessness causes severe atrophy of muscles and bones, and that it is impossible for the human body to remain healthy for long periods of weightlessness.

Living in the weightlessness of space is not something the human body can evolve to tolerate in the short term. It is contrary to our current nature. Now if someone could come up with some artificial gravity...

I repeat, can you say O'Neill? Large spinning colonies, centripital acceleration in lieu of gravity.

Yeah. ONeil was pretty much a delusional jerk. Spinning space colonies a single bullet sized meteroid could completely destroy. . .domes, really the stupidest things that one could build in space--single structures that kill everyone when they fail.

Geesss, someone lend us some sensibility.

[KitemanSA]

I repeat, can you say O'Neill? Large spinning colonies, centripital acceleration in lieu of gravity.

Yeah. ONeil was pretty much a delusional jerk. Spinning space colonies a single bullet sized meteroid could completely destroy. . .domes, really the stupidest things that one could build in space--single structures that kill everyone when they fail.

Geesss, someone lend us some sensibility.

Wow, another nightmare sufferer. D, you have some company.

Have you ever calculated how long it would take for a volume that size to depressurize? The solution to your nightmare is called... engineering. And by the way, it has been done to a large degree.

And if you don't trust the big ones, make interconnected small volumes and seal off the punctured ones till repaired.

However you wish to design it, there is no need to throw yourself down that well again.

Now if ANTI-gravity is ever developed and the well can be ignored...

[williatw]

Keep thinking that way and you guarantee we get nothing done. This is the O'Neil nonsense that has left us with no progress in space the last 5 decades. So long as space advocates lie to themselves about how space can be made a viable economic option, we'll have these inane dreams supplanting real plans. ROCKETS WILL NOT WORK. They are not safe, they are not quick, they are not convenient and they are not economical. ONLY A SPACEDRIVE CAN YIELD AN INTERPLANETARY SOCIETY.

Well I haven't said anything about O'Neill colonies. My idea is using Mars's location beyond earth laws reg taxes as a source of revenue. The bank of Mars, no taxes-- paying interest to depositors no records made available to any prying gov about who the investors are or how much they make. The other ideas I did mention like powersats/asteroid mining yes were mentioned by O’Neill but I would only see them happening much later. Even Musk does not think mining minerals would be valuable off planet because even so called "rare earths" are not that rare on earth. He (Musk) was also skeptical about the viability of powersats, at least near term. As for the idea of propellant less propulsion I wish Woodward luck. Heck I still hope that Extended Heim Theory will pan out. But until/unless something better comes along I would agree with Musk wanting to use the tools we have and see if we can make them better. I mean reusable chemical rockets would be a huge breakthrough, not as great as what you are talking about to be sure but very significant. Not to beat it to death but if I recall the assumptions under which O’Neill(and others) were operating at the time was that NASA’s shuttle would be very reusable, able to fly 50+ times a year turnaround times of 2 weeks or something. That’s what NASA claimed at the time (middle late 70’s), people at that time in the wake of the spectacular successes of the moon landings were apt to accept NASA's word on what it claimed the shuttle would be able to do.

[Skipjack]

IIUC, fusion has a much lower power density than fission. Fusion rules when it comes to avoiding nasty by-products; not in what it takes to generate propulsion. Either way, fission and fusion rockets CANNOT give us cheap and easy access to this planetary system, and certainly not the stars.

Well, there are several concepts for using fusion reactors for propulsion both for RLVs to LEO and interplanetary travel.
One concept of a fusion rocket engine would have an Isp of 1 million and more. That is nothing to laugh at and that would certainly open the door to solar system. John Slough has a concept for one that looks very promising (FRC based). IIRC that one could actually be used for launch vehicles as well.

Well I do think something like TRITON could give us a cheap enough propulsion system for explorers to take us vicariously to other worlds in our system.

Never heard of that one, got a link.
Edit, figured it out. It is a trimodal nuclear propulsion system. Basically a NERVA rocket with an afterburner and a electricity generation mode.
Not sure why you would call that a spacedrive though.

All the space drive concepts that I have heard of so far seem very far out there. Even Woodwards ME Thrusters only have a very, very low chance of working out in my book.

If Musk succeeds in building cheap reusable chemical rockets to orbit why couldn't nuclear rockets be used from earth orbit and beyond?

The most pressing problem for us is access to LEO. We absolutely HAVE to solve that before anything else can be attempted. The price for this has to be much lower than even Elon Musks reusable F9 can do. You can only do that with airplane like operations and very low turnarround times and a fully reusable RLV.
I am not 100&% sure that this can be done with chemical engines, definitely not with Musks (or anybody elses) concepts that I have seen for next generation LVs. Musk is on the right track, but still an order of magnitude to expensive for colonization of space.

If I was NASA, I would have killed the stupid SLS and put everything into next generation propulsion research and the research of other enabling technologies like MHD TPS (something that I had already proposed 20 years ago).

[Betruger]

We aren't going to sit around on Earth surface doing nothing for millenia, waiting to reach this technological readiness. Colonization now is better

I would not sit arround for millenia. The moon is close and we should be able to colonize it in the near term.

Or Mars. It's a toss up and frankly colonizing Mars is more inspiring. Unless it falls on its face for some reason (ie because it's too hard compared to e.g. the Moon).

[Skipjack]

Or Mars. It's a toss up and frankly colonizing Mars is more inspiring. Unless it falls on its face for some reason (ie because it's too hard compared to e.g. the Moon).

Well, the point of the conversation was that I suggested to terraform Mars first (as it is the planet in the vicinity where it seems the most possible). Since my concept for that would probably make Mars uninhabitable for millenia, I suggested that we could/should colonize the moon first and maybe have outposts on other nearby celestial bodies until Mars becomes habitable again.

[GIThruster]

And if you don't trust the big ones, make interconnected small volumes and seal off the punctured ones till repaired.

What then is the point behind the interconnection? I think what you don't appreciate is that it was this vision of wide open spaces that are easily compromised that was/is unworkable. The paintings of rotating stations with rivers running round the circumference, etc., are all useless, misleading hype. It is not safe in a pressurised environment to have these enormous rooms. The rooms were drawn and painted to form an appealing image in the mind, but as we now know, they have little to do with what living in space would be like. Rather, you have to be surrounded by large amounts of mass, most often in highly compartmentalized architecture, be it in a ship or a station. By contrast, "gravity wells" like the Earth are a better, safer, cheaper place to live.

Again just saying, its because of these phony pictures painted in the minds of many over decades, we are still talking about rockets rather than funding a space drive. A brilliant, hopeful vision is fine, so long as it doesn't distract us from how to become a truly space-faring race. It's important to look at these last 40 years and consider just what went wrong. Why almost no new accomplishments? My thesis is, we've gotten caught up majoring in the minors rather than focusing on the real challenges like a SpaceDrive.

[KitemanSA]

It's important to look at these last 40 years and consider just what went wrong. Why almost no new accomplishments? My thesis is, we've gotten caught up majoring in the minors rather than focusing on the real challenges like a SpaceDrive.

Typically, it is those who insist on swinging for the fence rather than placing the ball in play that are kept in the minors.

Personally, I am of the opinion that the reason nothing has happened in the past 40 years is the sad combination of NASA and the NSS. Any REAL hope for rapid space habitation died with the L5 Society.

[Skipjack]

As I said, I wont waste a second thought on colonization be it space stations or planets as long as we dont have cheap and relyable access to orbit. For that we need a technological breakthrough. NASA should be working on that instead of the darn stupid SLS that nobody needs and that wont go anywhere anyway.

[Betruger]

Or Mars. It's a toss up and frankly colonizing Mars is more inspiring. Unless it falls on its face for some reason (ie because it's too hard compared to e.g. the Moon).

Well, the point of the conversation was that I suggested to terraform Mars first (as it is the planet in the vicinity where it seems the most possible). Since my concept for that would probably make Mars uninhabitable for millenia, I suggested that we could/should colonize the moon first and maybe have outposts on other nearby celestial bodies until Mars becomes habitable again.

That's not what I was getting at, but putting that aside for a moment - I don't see how you figure that Mars terraforming is anything but such a very long term prospect that colonization couldn't be worthwhile in the mean time.

Again just saying, its because of these phony pictures painted in the minds of many over decades, we are still talking about rockets rather than funding a space drive. A brilliant, hopeful vision is fine, so long as it doesn't distract us from how to become a truly space-faring race.

This spacedrive is just fantasy. Right now.
It's nonsense to pretend a fantasy spacedrive is worth focusing on at the expense of things that work right here and now. The best choice isn't imaginary revolutions like ME but doing both, correctly. There's no such dichotomy that opposes funding conventional rockets to funding very low readiness tech like MEP.

Till these "spacedrive" fruits do materialize, EG when an ME article levitates into one of those conventions, the Musk way of "caveman" economies of scale are the best thing to do.

[williatw]

Or Mars. It's a toss up and frankly colonizing Mars is more inspiring. Unless it falls on its face for some reason (ie because it's too hard compared to e.g. the Moon).

Well, the point of the conversation was that I suggested to terraform Mars first (as it is the planet in the vicinity where it seems the most possible). Since my concept for that would probably make Mars uninhabitable for millenia, I suggested that we could/should colonize the moon first and maybe have outposts on other nearby celestial bodies until Mars becomes habitable again.

That's not what I was getting at, but putting that aside for a moment - I don't see how you figure that Mars terraforming is anything but such a very long term prospect that colonization couldn't be worthwhile in the mean time.

Again just saying, its because of these phony pictures painted in the minds of many over decades, we are still talking about rockets rather than funding a space drive. A brilliant, hopeful vision is fine, so long as it doesn't distract us from how to become a truly space-faring race.

This spacedrive is just fantasy. Right now.
It's nonsense to pretend a fantasy spacedrive is worth focusing on at the expense of things that work right here and now. The best choice isn't imaginary revolutions like ME but doing both, correctly. There's no such dichotomy that opposes funding conventional rockets to funding very low readiness tech like MEP.
Till these "spacedrive" fruits do materialize, EG when an ME article levitates into one of those conventions, the Musk way of "caveman" economies of scale are the best thing to do.

I agree. Musk's approach is what can I do with the tools at hand? He is looking at it like the business man he is. He is saying if he can get the cost of going to Mars down to 500K per person, he can make a profit. He estimates that at least 8000(probably a lot more) around the world could be able to afford it. Never mind why they want to go he is the shipper not his problem. 500 people + equipment on mars is a colony. My idea is what could they do to earn a living, again using the tools available. Sure there are better tools and better ideas, but better to use what we have until better becomes reality.

[Skipjack]

That's not what I was getting at, but putting that aside for a moment - I don't see how you figure that Mars terraforming is anything but such a very long term prospect that colonization couldn't be worthwhile in the mean time.

Please read back in the thread. My concept for terraforming would probably make Mars uninhabitable for millenia.

[Skipjack]

It's nonsense to pretend a fantasy spacedrive is worth focusing on at the expense of things that work right here and now. The best choice isn't imaginary revolutions like ME but doing both, correctly. There's no such dichotomy that opposes funding conventional rockets to funding very low readiness tech like MEP.
Till these "spacedrive" fruits do materialize, EG when an ME article levitates into one of those conventions, the Musk way of "caveman" economies of scale are the best thing to do.

Which is why it makes sense for NASA to fund several conventional approaches to space access like Elon Musks via the commercial crew program. But unfortunately they are currently wasting billions on the pork rocket SLS. That money would be better spent on researching break through technologies. If NASA invested the billions, they are spending on the SLS, into research into fusion reactor concepts that would be applicable to propulsion, they would achieve much more with that (and maybe even solve the worlds energy problem at the same time).

[williatw]

That's not what I was getting at, but putting that aside for a moment - I don't see how you figure that Mars terraforming is anything but such a very long term prospect that colonization couldn't be worthwhile in the mean time.

Please read back in the thread. My concept for terraforming would probably make Mars uninhabitable for millenia.

Why would we use your idea? Why would you want to make mars uninhabitable for millenia when there are other ideas that wouldn't? Like for instance, building factories on mars to use native raw materials to produce super greenhouse gases. They could make mars have a warm environment with earth like temperatures with a thick atmosphere and liquid water on the surface in mere decades not millenia.

[Skipjack]

Why would we use your idea? Why would you want to make mars uninhabitable for millenia when there are other ideas that wouldn't? Like for instance, building factories on mars to use native raw materials to produce super greenhouse gases. They could make mars have a warm environment with earth like temperatures with a thick atmosphere and liquid water on the surface in mere decades not millenia.

You understand the scales that we are talking about there, right?
It is often amazing to me how people can underestimate planetary scales.
Also, without a magnetic field, the solar wind will quickly "blow" away that little atmosphere that you are producing there. My concept was about giving mars' tectonics a slight kick in the hope of increasing the magnetic field a bit. For this you need a deep impact.
I also mentioned an alternative concept that would use multiple smaller impacts of icy asteroids or impacts of smaller rocky asteroids into existing ice fields on Mars to create an atmosphere of some sorts on it (with green house gases etc). But even with that solution (which is not my idea, but was proposed in several serious studies on mars colonization and terraforming), I doubt you would want to be there, when it happens. So again, large scale colonization does not make sense prior to terraforming.
The second solution would also only be temporary until the solar wind ruins everything again. I honestly dont know how long that would take then. Probably hundreds of thousands of years, maybe millions depending on how dense the created atmosphere was to begin with.
The question is of course. What do you do with a fully populated Mars that is about to become uninhabitable due to loss of atmosphere? You cant simply drop more asteroids into a densly populated planet. So what is the backup plan for this?
Certainly lots of things to think about.
Moon makes much more sense for first colonization attempts. Mars in its current state has almost no advantage over the moon. It is only much further away. You would still have to employ almost all the same techniques on both bodies (underground structures, etc). The moon is much easier to reach though and that makes it much more interesting for the near term.

Still, whether it is mars or moon, you need to get to LEO first.