Thread: It ain't the kind of place to raise your kids? Board: Oblivion / Ship of Fools.
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Posted by LeRoc (# 3216) on
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Alright, I'm just going to throw this in here. I think that we should colonise Mars.
I admit that my reasons for this aren't fully rational. A lot has been said about the benefits this may bring to science, commerce, health. And that may well be true.
But to me this is also about a sense of purpose. There is this whole Universe out there, with so many possibilities. And we're just going to stay on Earth? That doesn't make sense.
(Please come to a conclusion quickly. The next launch window for Mars will be in 2018 ![[Smile]](smile.gif)
)
Posted by mr cheesy (# 3330) on
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So do the benefits justify the potential costs? Should that even be part of the debate?
[sorry..]
[ 31. March 2016, 10:44: Message edited by: mr cheesy ]
Posted by LeRoc (# 3216) on
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quote:
mr cheesy: So do the benefits justify the potential costs? Should that even be part of the debate?
I'm not sure. Isn't the capitalist system supposed to be promoting innovation, moving humanity forward? Here it seems that our economical system is holding us back.
Posted by Humble Servant (# 18391) on
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quote:
Originally posted by mr cheesy:
So do the benefits justify the potential costs? Should that even be part of the debate?
[sorry..]
The benefits are impossible to foresee, let alone quantify.
It could cost the Earth. If we have an escape route, could we potentially take even less care of our current home than we currently do?
Posted by Martin60 (# 368) on
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Utterly impossible. Not without $trillion materials breakthroughs which are probably utterly unattainable even with a trillion bucks of useless research like solving nuclear fusion, which would also be necessary.
Kim Stanley Robinson's superb Red, Green and Blue Mars trilogy is as fantastical as Tolkein.
Science fiction - robots, manned space travel, colonization - is all utter nonsense because of the energetics.
It's Earth or nowt.
Posted by Alan Cresswell (# 31) on
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Mars will never (well, in the plausible future) be an escape route from Earth. It will never be possible using chemical rockets to lift more than a miniscule fraction of our population out of our gravity well (although, once we've done that getting anywhere else in the Solar System is a piece of cake). And, if we can manage to develop an alternative launch mechanism then in the process we'll probably solve most of the problems on Earth and won't need an escape.
Posted by LeRoc (# 3216) on
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quote:
Humble Servant: It could cost the Earth. If we have an escape route, could we potentially take even less care of our current home than we currently do?
Maybe, although it would be a rather long-term concern. We're far away from Mars being so comfortable to us that way can think "what the heck" about Earth.
If anything, I think that space exploration can help grow environmental conscience. Photographs like that of the Earth from the Moon and the Pale Blue Dot have already done that.
I'm not sure to which extent space exploration has boosted solar panel technology; I'm guessing that it has to some degree. There are probably other technologies as well that also have environmental uses.
And if people are going to live on Mars, letting nothing go to waste will probably be part of their mind set.
Posted by Alan Cresswell (# 31) on
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quote:
Originally posted by LeRoc:
Isn't the capitalist system supposed to be promoting innovation, moving humanity forward?
When there is a likely short to medium term return on investment then capitalism does seem to work at developing new technologies. We're beginning to see that in launch technologies that for 60 years have been dominated by superpowers using over-grown ballistic missiles - in part because the space race gave them an excuse to research more powerful missile technology to carry their infernal MADness.
But, space is beginning to bring in commercial returns. Satellite communications, weather forecasting, positioning are all bringing in money. And, private companies are beginning to put their own equipment into orbit - and doing it very cheaply compared to the likes of NASA. Piggy-backing on that, private industry is developing launch capability that at least for small payloads should beat the missiles hands down in cost.
Mars, however, has no prospect of short or medium term economic return. At present about the only thing that would produce some return on investment is the sale of exclusive TV broadcast/streaming rights. And, that will be a fraction of the cost. You may find a few investors willing to put something into a venture with possible returns in 50 years. An investment when there isn't even an outline of what commercial returns there will be is not going to happen. For that you want donors, not investors.
Posted by LeRoc (# 3216) on
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quote:
Martin60: Not without $trillion materials breakthroughs
I don't know how realistic it is, but the current projections of the Mars Society are around $55bn.
Posted by Alan Cresswell (# 31) on
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Since the Mars Society FAQs say $30b there's a factor of two inflation in there somewhere already. Personally, I would expect another factor of two, or two, to creep in.
The biggest issue with the Mars Direct plan is that it requires a functioning nuclear reactor to be landed remotely on Mars and operate unsupervised for at least 18 months to generate the fuel for the return trip. To get permission to launch a reactor would require such a high level of safety that the costs will spiral rapidly, as will the weight of the launch vehicle as extra redundant systems are added.
Posted by Humble Servant (# 18391) on
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quote:
Originally posted by Alan Cresswell:
It will never be possible using chemical rockets to lift more than a miniscule fraction of our population out of our gravity well
That's all we need to preserve the species. Individuals without the resources or power will be expendable.
Posted by LeRoc (# 3216) on
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quote:
Alan Cresswell: The biggest issue with the Mars Direct plan is that it requires a functioning nuclear reactor to be landed remotely on Mars and operate unsupervised for at least 18 months to generate the fuel for the return trip. To get permission to launch a reactor would require such a high level of safety that the costs will spiral rapidly, as will the weight of the launch vehicle as extra redundant systems are added.
Hmm, I'm not too keen on nuclear power. Of course, we've sent around 30 fission generators to space already, but I guess this one would be much bigger.
Posted by no prophet's flag is set so... (# 15560) on
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What's the morality of Mars colonisation? Considering how well we have sorted out poverty, pollution, war. Dystopianly, perhaps we should noisily blow each other up and quietly poison and starve just one planet.
Posted by Boogie (# 13538) on
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I've only just got the reference in the OP
Whether it ever happens or not I think it's a great thing to strive for. Just like the moon landings, a lot of unforeseen good will come out of it too imo.
We humans need goals and aims or we tend to turn in on each other. A 'Mars race' between superpowers would deflect from all the pointless willy waving too.
Posted by LeRoc (# 3216) on
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quote:
no prophet's flag is set so...: What's the morality of Mars colonisation? Considering how well we have sorted out poverty, pollution, war.
That's valid concern; no use going to Mars if we do the same bullshit there that we do here.
If Mars is currently lifeless though, at least we won't have to worry too much about poisoning and starving the planet.
Posted by Alan Cresswell (# 31) on
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quote:
Originally posted by LeRoc:
quote:
Alan Cresswell: The biggest issue with the Mars Direct plan is that it requires a functioning nuclear reactor to be landed remotely on Mars and operate unsupervised for at least 18 months to generate the fuel for the return trip. To get permission to launch a reactor would require such a high level of safety that the costs will spiral rapidly, as will the weight of the launch vehicle as extra redundant systems are added.
Hmm, I'm not too keen on nuclear power. Of course, we've sent around 30 fission generators to space already, but I guess this one would be much bigger.
Yes, the reactors currently sent into space have been about 5kW, or less, and typically operate for a few years. And, least one of them has come back down to Earth spreading radioactive debris across a very large area. With at least two more launch failures where the core was ejected to splash down into the sea. A 5-10% crash back to Earth rate for nuclear reactors is simply not good enough.
And, the Mars Direct reactor would need to be significantly bigger, and ideally operate long enough to generate fuel for subsequent missions as well, so for 10 years or more. The Zubrin paper envisages a 100kWe reactor.
Posted by Martin60 (# 368) on
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A mere hundred billion dollar mission will only START a British Antarctic Survey level post.
This is just pathetic hubris, like nuclear fusion. And as Alan has said, if we can crack something like that, we can crack anything here on Earth.
But we CAN'T crack anything like that. Ever. Fusion or a space elevator. Going off-world needs both.
Posted by Augustine the Aleut (# 1472) on
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A scientist friend (sets of initials and a Canada Research Chair) once told me that she favoured a mission to Mars because this was the only way to get serious funding approved for basic research. She pointed out that the 1960s space exploration effort produced incredible collateral products and techniques, which have had much to do with the improvement of our quality of life, and the electronic productivity boom of the past 25 years. She was very convincing, listing lots of things which to which I did hot pay sufficient attention to retail to shipmates.
Posted by Pigwidgeon (# 10192) on
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quote:
Originally posted by LeRoc:
(Please come to a conclusion quickly. The next launch window for Mars will be in 2018 )
If you could offer this trip for January 20, 2017 you might get a lot of Americans wanting to go, depending what happens on November 8, 2016.
Posted by HCH (# 14313) on
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It is quite possible that human beings will not be able to colonize Mars due to its light gravity. By now there is quite a lot of data available about the effects of zero-G, but low-G is more of a mystery.
I would not assume that an expedition to Mars will necessarily travel unpowered on a doubly-tangent ellipse orbit. People have pointed out that one could build a continuous-thrust ship that would get there much faster.
It is quite likely that someone will build orbiting habitats, perhaps at the Lagrange points. I don't know that I would care to live there.
Posted by SusanDoris (# 12618) on
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It seems reasonable to assume that, well within the billion or more years before this planet becomes impossible for human life, scientist will have discovered a means of moving us, or as many of the people still livingkk who can and wish to go, to some other suitable planet.
I suppose it seems daft to say so, but I am sad for those who will know, in that far distant time, extinction is not that many generations away.
[ 31. March 2016, 16:25: Message edited by: SusanDoris ]
Posted by Martin60 (# 368) on
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Humanity cannot possibly last that long, 1% if that.
Posted by LeRoc (# 3216) on
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quote:
Alan Cresswell: The Zubrin paper envisages a 100kWe reactor.
Yes, that's a rather big obstacle.
@Pigwidgeon:
quote:
HCH: It is quite possible that human beings will not be able to colonize Mars due to its light gravity. By now there is quite a lot of data available about the effects of zero-G, but low-G is more of a mystery.
Interesting. Are you expecting low-G to be much different from zero-G? What this tells me that it might be better to experiment with the Moon first. (At least we won't have to deal with launch windows.)
quote:
SusanDoris: It seems reasonable to assume that, well within the billion or more years before this planet becomes impossible for human life, scientist will have discovered a means of moving us, or as many of the people still livingkk who can and wish to go, to some other suitable planet.
I think you're talking about the time when the Sun will begin to expand, which will be more than a billion years from now. I agree with you that this will give us plenty of time to come up with a solution to move the whole population somewhere else.
Of course, there are many things that could threaten us before that. A large meteor. Or more likely, we ourselves.
Posted by Pigwidgeon (# 10192) on
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quote:
Originally posted by LeRoc:
What this tells me that it might be better to experiment with the Moon first. (At least we won't have to deal with launch windows.)
A rather oddly-attired woman on public transportation a few weeks ago was trying to convince my friend and me that we* should colonize the moon since the gravity is 1/6 that of earth.
(* not the two of us specifically, but humankind in general I assume.)
Posted by LeRoc (# 3216) on
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quote:
Pigwidgeon: A rather oddly-attired woman on public transportation a few weeks ago was trying to convince my friend and me that we* should colonize the moon since the gravity is 1/6 that of earth.
According to her, what would the benefits of this low gravity be?
Posted by Ariel (# 58) on
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quote:
Originally posted by LeRoc:
Alright, I'm just going to throw this in here. I think that we should colonise Mars.
...
But to me this is also about a sense of purpose. There is this whole Universe out there, with so many possibilities. And we're just going to stay on Earth? That doesn't make sense.
It doesn't make sense to shove off to a cold dead planet where the main excitement is scrambling in and out of dusty red craters, clad in spacesuits because you can't breathe the atmosphere. I think it would be stultifyingly dull, and everything would have to be imported and therefore expensive, and you'd have to live under some kind of dome that enabled earth-type living conditions, gravity, light, heat and water.
If you're going to colonize, at least pick an interesting planet with water and plants that can support earth-type lifeforms. I can't see Mars as much other than a penal colony.
Posted by Penny S (# 14768) on
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quote:
Originally posted by Humble Servant:
quote:
Originally posted by Alan Cresswell:
It will never be possible using chemical rockets to lift more than a miniscule fraction of our population out of our gravity well
That's all we need to preserve the species. Individuals without the resources or power will be expendable.
So the survival of the species depends on a small self selected bunch with money and a debatable ability to recognise the appropriate type of woman to perpetuate us. Trump? Murdoch? A gene bottleneck is not going to be a good thing.
Posted by Nicolemr (# 28) on
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quote:
If you're going to colonize, at least pick an interesting planet with water and plants that can support earth-type lifeforms.
First we have to find such a planet. ( Mars does have water, btw, quite a bit of it actually. Just all tied up in ice.)
Mars is the first step in moving out into the stars. We aren't going to get any planet more habitable in this solar system.
Posted by Huia (# 3473) on
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Oh goody! A whole new planet for people to ruin. One was not nearly enough ![[Roll Eyes]](rolleyes.gif)
Huia
Posted by LeRoc (# 3216) on
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quote:
Ariel: It doesn't make sense to shove off to a cold dead planet where the main excitement is scrambling in and out of dusty red craters, clad in spacesuits because you can't breathe the atmosphere.
I see what you mean. I guess what you're saying is even more true about the Moon, which is basically a dull bunch of rocks. Mars is geologically quite interesting though. I find this video (2:20min) rather impressive. And of course, not everyone is like you. Volunteers are lining up to live on Mars.
And echoing what others have said, perhaps humanity living on Earth for the next billion years would be pretty boring too.
quote:
Huia: Oh goody! A whole new planet for people to ruin. One was not nearly enough
Like I've said a little earlier, if Mars is currently lifeless, I wouldn't be too upset about that.
Posted by Ariel (# 58) on
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quote:
Originally posted by LeRoc:
I see what you mean. I guess what you're saying is even more true about the Moon, which is basically a dull bunch of rocks.
The Moon gives me the creeps. It seems so dead and silent, and there's the dark side.
People are different and there won't be any shortage of volunteers to go and live on Mars. But I love the countryside on our own planet, and the wonderful variety of plants and birds and animals, and there wouldn't be any of that on Mars, no new species that you could enjoy getting to know (or I suppose be wary of/have to eradicate in order to live there safely). There's an incredible amount of variety (and beauty) packed into this planet and we're still discovering things about it. I'm not at all sure that Mars would have half as much to offer.
Posted by Pigwidgeon (# 10192) on
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quote:
Originally posted by LeRoc:
quote:
Pigwidgeon: A rather oddly-attired woman on public transportation a few weeks ago was trying to convince my friend and me that we* should colonize the moon since the gravity is 1/6 that of earth.
According to her, what would the benefits of this low gravity be?
She didn't really say -- perhaps she thought it would be nice to weigh less without having to go on a diet. She didn't strike me as being terribly rational.
Posted by LeRoc (# 3216) on
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quote:
Ariel: The Moon gives me the creeps. It seems so dead and silent, and there's the dark side.
Maybe there is a misunderstanding here, but there isn't a side of the Moon that always stays dark. All places on the Moon have days and nights, just as on Earth. (The difference is that one day-night cycle lasts a month.)
Posted by Ariel (# 58) on
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Still creepy. There wouldn't be any shortage of people willing to live on the Moon, but marketing properties that get no light for an entire month, or conversely, are floodlit for days on end, is going to be interesting.
Posted by Ricardus (# 8757) on
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quote:
Originally posted by LeRoc:
quote:
Pigwidgeon: A rather oddly-attired woman on public transportation a few weeks ago was trying to convince my friend and me that we* should colonize the moon since the gravity is 1/6 that of earth.
According to her, what would the benefits of this low gravity be?
Less energy required to move stuff round, and therefore to manufacture stuff? Then use space elevators to transfer the stuff between the Moon and Earth.
Posted by LeRoc (# 3216) on
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quote:
Pigwidgeon: She didn't really say -- perhaps she thought it would be nice to weigh less without having to go on a diet.
Heh, funny.
I know Zubrin is against it, but I wouldn't mind starting on the Moon. The way I understand it, it's getting more and more difficult for billionaires to find something to do with their money. That's why they keep buying Premier League teams and running for president.
Why can't we entice one of them to fund a base on the Moon? Let him call it Trump Base, or erect a tower there as a homage to his penis, whatever. He can do a reality TV show there if he wants. As long as the money keeps flowing.
At least the general public would get used to the idea of people living off Earth. We could have research there, some tourism, telescopes unhindered by an atmosphere … And we could test what it would be like to live based on machines that extract the things we need from rocks.
I think that all of this would make the next step to Mars much more natural.
Posted by LeRoc (# 3216) on
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quote:
Ricardus: Less energy required to move stuff round, and therefore to manufacture stuff?
I know, I was just wondering what this woman said to Pigwidgeon.
quote:
Ricardus: Then use space elevators to transfer the stuff between the Moon and Earth.
As long as they won't use them to hurl rocks at Earth
quote:
Ariel: marketing properties that get no light for an entire month, or conversely, are floodlit for days on end, is going to be interesting.
It's two weeks of light, two weeks of dark. And I imagine that people will be living underground anyway?
BTW Earlier on this thread I referred to the 'Earthrise' photograph. I just realised that mr cheesy uses it as his Ship avatar.
[ 31. March 2016, 19:01: Message edited by: LeRoc ]
Posted by Lamb Chopped (# 5528) on
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Why is it so important to preserve the species?
I'm rather fond of it, myself. But even I know that it's going to come to an end eventually. And if we're fool enough to make it a premature end by our own idiocy, perhaps we ought to do it in our current safely-contained planet, instead of spewing our screw-ups over other planets too.
Now you could talk me into extraplanetary travel on other grounds. But preserving the species, meh.
Posted by no prophet's flag is set so... (# 15560) on
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Well, if we're going to fantasize - planets outside our solar system are not going to be colonization destinations any time soon, if ever - I want to be on the USS Enterprise with Captain Picard. Exploring the galaxay and using the holodeck. And drinking prune juice with Worf or maybe some left over green stuff from Scotty's stash in the previous series (skip the synthahol please).
Posted by Hedgehog (# 14125) on
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quote:
Originally posted by LeRoc:
quote:
Ariel: marketing properties that get no light for an entire month, or conversely, are floodlit for days on end, is going to be interesting.
It's two weeks of light, two weeks of dark. And I imagine that people will be living underground anyway?
Considering there are cities on Earth (like Trondheim, Norway) that only get about ten hours of daylight in all of December, I suspect people could adjust.
Say what you will about humans, but they are adaptable.
Once one gets to Mars, how practical would it be to terraform it? Assuming you set up a huge greenhouse to keep things warm enough to grow, I would think it would still take Quite A Long Time to create a breathable atmosphere and manufacture a greenhouse effect so that one could live outdoors.
Posted by LeRoc (# 3216) on
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quote:
Lamb Chopped: Why is it so important to preserve the species?
I'm rather fond of it, myself. But even I know that it's going to come to an end eventually.
Species preservation is one of the more far-fetched arguments for Mars colonisation. But I think there is a difference between accepting that we'll come to an end eventually, and not doing anything specific threats. If only because of our survival instinct. Or for our children.
quote:
no prophet's flag is set so...: planets outside our solar system are not going to be colonization destinations any time soon
True. This might be a very first step though.
quote:
Hedgehog: I would think it would still take Quite A Long Time to create a breathable atmosphere and manufacture a greenhouse effect so that one could live outdoors.
Yes, that would definitely be a longer-term project. I've seen it estimated at a couple of centuries.
Posted by rolyn (# 16840) on
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quote:
Originally posted by Boogie:
We humans need goals and aims or we tend to turn in on each other. A 'Mars race' between superpowers would deflect from all the pointless willy waving too.
....so building a giant phallic rocket in a clamour to get to our moon and simply poke a pole in it wasn't willy waving?
Back to OP I suppose it might be alright to bring up kids on Mars, so long as you get them to wipe poisonous Martian dust off their shoes before coming in from playing outdoors.
Posted by LeRoc (# 3216) on
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quote:
rolyn: ....so building a giant phallic rocket in a clamour to get to our moon and simply poke a pole in it wasn't willy waving?
It beats throwing rockets at each other (which I think is what Boogie was trying to say).
Posted by Boogie (# 13538) on
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quote:
Originally posted by LeRoc:
quote:
rolyn: ....so building a giant phallic rocket in a clamour to get to our moon and simply poke a pole in it wasn't willy waving?
It beats throwing rockets at each other (which I think is what Boogie was trying to say).
It was
Posted by HCH (# 14313) on
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If you insist that we absolutely must have another planet and you take a long enough view, how about this: find a way to pull Venus farther out from the Sun, find a way to cool it down and then terraform it, perhaps starting with plenty of bacteria for photosynthesis. (Yes, there are serious engineering challenges, but given enough time, it might be possible.)
Posted by LeRoc (# 3216) on
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quote:
HCH: find a way to pull Venus farther out from the Sun, find a way to cool it down and then terraform it
Heh, I've seen hypothetical methods that involve building an artificial ring around the planet.
I'd love to have a holiday in the lush forests of Ishtar.
Posted by Martin60 (# 368) on
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HCH uh huh.
Will we have conquered the common cold by then too?
Posted by georgiaboy (# 11294) on
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All of you who have not done so should certainly read C S Lewis's 'Out of the Silent Planet.'
There's plenty of food for thought therein.
Posted by Martin60 (# 368) on
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Lovely tale. No food for technological thought whatsoever, ever.
Posted by Kaplan Corday (# 16119) on
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quote:
Originally posted by Lamb Chopped:
Why is it so important to preserve the species?
C.S. Lewis: "For the species, as for each man, mere longevity seems to me a contemptible ideal."
Posted by Kaplan Corday (# 16119) on
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quote:
Originally posted by LeRoc:
Isn't the capitalist system supposed to be promoting innovation, moving humanity forward?
It was communism which promoted innovation and moved humanity forward by producing the first astronaut.
Just sayin'.
[ 31. March 2016, 23:33: Message edited by: Kaplan Corday ]
Posted by Alan Cresswell (# 31) on
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quote:
Originally posted by LeRoc:
quote:
HCH: It is quite possible that human beings will not be able to colonize Mars due to its light gravity. By now there is quite a lot of data available about the effects of zero-G, but low-G is more of a mystery.
Interesting. Are you expecting low-G to be much different from zero-G? What this tells me that it might be better to experiment with the Moon first. (At least we won't have to deal with launch windows.)
There are several good reasons for starting with the Moon. Better understanding of the effects of low term low-G would be one of them (when it comes down to it we only know about the effects of zero-G on a small number of individuals for a few months - and would low-G be similar but less intense or would we find entirely new effects?).
It would be a test bed for habitats - testing on Earth is good, but ultimately if something goes wrong you just open the door. And, psychology, put a habitat on the dark side and add a few minutes delay to communications. How do people react to that non-instant communication and not being able to look out of the window to see home? Yes, there aren't many launch window restrictions. But, we could always add in a delay so that the Lunar test subjects still have to live with the "we'll get it to you in 30 months" if they forgot something.
At a practical level, if (and, it's an if) a lunar colony can mine materials and construct components of the Mars mission spaceships it will significantly reduce the amount of material we'd need to lift out of our gravity well. If the lunar colonists can mine and enrich uranium that would remove the launch risks of the reactors needed. And, if the effects of lunar gravity on health are minor, it might be possible to run the rotating tether proposed to simulate gravity on the Mars flights at a lower speed, reducing the strain on the tether and the fuel needed to accelerate/decelerate the rotation.
Also the prospect of bring raw materials to earth from the moon (which, we're not going to do from Mars for several decades, if at all) might be sufficient for private investment in the launch and habitat facility development - money that won't need to be found again for Mars.
Posted by Pigwidgeon (# 10192) on
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quote:
Originally posted by LeRoc:
BTW Earlier on this thread I referred to the 'Earthrise' photograph. I just realised that mr cheesy uses it as his Ship avatar.
So does Soror Magna.
Posted by Penny S (# 14768) on
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There does seem to be a small problem in the mining stuff direction, as most Earth type deposits of useful stuff seem to have been formed as a result of activity associated with a) plate tectonics, and b) water. And, yes, I realise that plate tectonics itself depends on water, but the concentration and deposition of minerals depends on much more intimate connections between the stuff and the water. Uranium, I seem to recall, needs a change in pH to precipitate dissolved metal from solution into ore bodies.
The Moon is rather short of water. Ditto Venus. Ditto Mars.
Iron and alloyed metals are available from asteroids formed by the breaking up of bodies which were large enough to form cores, but would need a lot of work to separate elements out.
[ 01. April 2016, 05:48: Message edited by: Penny S ]
Posted by Boogie (# 13538) on
:
quote:
Originally posted by Huia:
Oh goody! A whole new planet for people to ruin. One was not nearly enough
I doubt if the planet will care either way.
Posted by Martin60 (# 368) on
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It ain't gonna happen.
EVER.
Like commercial fusion.
Ever.
Utter childish fantasy.
Here's another: snake oil power.
Posted by Ariel (# 58) on
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quote:
Originally posted by LeRoc:
It's two weeks of light, two weeks of dark. And I imagine that people will be living underground anyway?
It sounds even more alluring. Not only are you on a cold dead planet with no seasons, you’re now stuck underground with no natural light and no view.
quote:
From Hedgehog]
Considering there are cities on Earth (like Trondheim, Norway) that only get about ten hours of daylight in all of December, I suspect people could adjust.
Yes, however the Arctic Circle isn’t most people’s choice of place to migrate to. And the lack of sunlight adds to the depression factor. The only way people could cope with living on the Moon would be to make the conditions as Earth-like as possible, in which case you might just as well stay on Earth.
Posted by LeRoc (# 3216) on
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quote:
Ariel: It sounds even more alluring. Not only are you on a cold dead planet with no seasons, you’re now stuck underground with no natural light and no view.
But think about the low-G sex!
Posted by Boogie (# 13538) on
:
quote:
Originally posted by Martin60:
It ain't gonna happen.
EVER.
Like commercial fusion.
Ever.
Utter childish fantasy.
Never say never. Think of the things we use routinely now and once thought were science fiction - even in our own lifetimes. (eg computer in your pocket which can make face-to-face calls to anyone)
[ 01. April 2016, 07:40: Message edited by: Boogie ]
Posted by Ariel (# 58) on
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quote:
Originally posted by LeRoc:
But think about the low-G sex!
I'd rather not, thank you.
Posted by SusanDoris (# 12618) on
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quote:
Originally posted by Lamb Chopped:
Why is it so important to preserve the species?
It is only important to us humans of course! That is why humans of the future will do everything they can to remove at least some of us to somewhere we stand a chance of not being annihilated.
Posted by Alan Cresswell (# 31) on
:
quote:
Originally posted by Boogie:
Think of the things we use routinely now and once thought were science fiction - even in our own lifetimes. (eg computer in your pocket which can make face-to-face calls to anyone)
I've heard it said that if you brought someone from Victorian London and showed them the latest smartphone they'd be impressed at our ability to access the sum total of human knowledge from anywhere. And, totally bemused that we use it to share photos of cats.
Posted by Alan Cresswell (# 31) on
:
quote:
Originally posted by Ariel:
quote:
Originally posted by LeRoc:
It's two weeks of light, two weeks of dark. And I imagine that people will be living underground anyway?
It sounds even more alluring. Not only are you on a cold dead planet with no seasons, you’re now stuck underground with no natural light and no view.
When it comes down to it, the Moon is an extremely hostile environment, only marginally less hostile than open space (the Moon, at least, has some gravity and half the time you're shielded from solar radiation). And, the psychological aspects of living there are certainly part of the hostility of the environment. You may as well be sitting in a tin can, far above the Earth.
Mars is a bit less hostile. The gravity is higher. There's an atmosphere, if a thin one, to provide some protection from radiation - and, being further from the Sun there's less radiation. On the other hand, there's enough atmosphere to whip up some very nasty sand storms.
It will take a particular kind of person to survive, let alone enjoy, the experience of living in either place. Probably most of us do not have the right stuff.
Posted by LeRoc (# 3216) on
:
quote:
Penny S: There does seem to be a small problem in the mining stuff direction, as most Earth type deposits of useful stuff seem to have been formed as a result of activity associated with a) plate tectonics, and b) water.
I don't think people are thinking about mining for iron or something like that on the moon. As you said, better go to the asteroids for that.
What's mostly being talked about is deploying machines like this to scrape off the rocks and sand and extract stuff like phosphorus and potassium from there. Hardly worth sending to Earth, but invaluable for the Loonies when they want to start their hydroponics agriculture.
quote:
Originally posted by Pigwidgeon:
quote:
Originally posted by LeRoc:
BTW Earlier on this thread I referred to the 'Earthrise' photograph. I just realised that mr cheesy uses it as his Ship avatar.
So does Soror Magna.
I know. I was looking at people who had posted on this thread.
quote:
Alan Cresswell: There are several good reasons for starting with the Moon.
Besides the ones you mentioned, I don't think we should underestimate the psychological effect it will have on people back on Earth to have people living on the Moon.
(PS I like some of the pop culture references on this thread!)
Posted by Martin60 (# 368) on
:
quote:
Originally posted by Boogie:
quote:
Originally posted by Martin60:
It ain't gonna happen.
EVER.
Like commercial fusion.
Ever.
Utter childish fantasy.
Never say never. Think of the things we use routinely now and once thought were science fiction - even in our own lifetimes. (eg computer in your pocket which can make face-to-face calls to anyone)
It's ALL about energy scale. We can be as accumulatively clever as we like for as long as we like it will make NO dent on fusion or colonizing the solar system let alone beyond.
Other vanity projects like AI and matter transmission are just as absurd.
Posted by Crœsos (# 238) on
:
quote:
Originally posted by Alan Cresswell:
When it comes down to it, the Moon is an extremely hostile environment, only marginally less hostile than open space (the Moon, at least, has some gravity and half the time you're shielded from solar radiation). And, the psychological aspects of living there are certainly part of the hostility of the environment. You may as well be sitting in a tin can, far above the Earth.
Mars is a bit less hostile. The gravity is higher. There's an atmosphere, if a thin one, to provide some protection from radiation - and, being further from the Sun there's less radiation. On the other hand, there's enough atmosphere to whip up some very nasty sand storms.
It will take a particular kind of person to survive, let alone enjoy, the experience of living in either place. Probably most of us do not have the right stuff.
This seems to be the biggest obstacle to any effort to build an actual colony (as opposed to a research base or some kind of mining/extraction outpost) on Mars. Humans tend not to do that sort of thing. There are lots of hostile environments right here on Earth (though less hostile than Mars). When humans discover some reason to go to those places they usually don't build a self-sustaining city there. They usually build a temporary outpost sufficient to whatever purpose they have for going there and rotate a crews in and out. Think of offshore oil platforms, or Antarctic research bases. A self-sustaining colony worthy of the name is several orders of magnitude more complicated than these kinds of outposts.
Given our reluctance to "colonize" the Gobi or Sahara (for example), why do people think there's a huge demand for colonizing Mars?
Posted by Martin60 (# 368) on
:
We're in the shaded bit of this where the x-axis is energy and the y is complexity as to what's EVER achievable. The z-axis perpendicular to this is time. Shrink to a dot and that's us 200,000 years ago. Expand to a postage stamp and that's where we're at. We've gone from banging rocks together to detonating the Tsar-bomba on the horizontal. Heating water with hot rocks in unglazed pots to Lacanian analysis on the vertical (I'm open to better). Time is also synonymous with population.
Archimedes lever is forever out there, along with fusion, radio frequency cavity thrust propulsion and social justice.
Posted by LeRoc (# 3216) on
:
quote:
Martin60: We're in the shaded bit of this where the x-axis is energy and the y is complexity as to what's EVER achievable.
So, we can do low-energy complex things and high-energy simple things?
Posted by Alan Cresswell (# 31) on
:
In scientific research proposals there's a description that describes an idea on a 'difficulty' scale (x: easy to impossible) and an 'interest' scale (y: mundane to world-breaking exciting). Research proposals that are both world-breaking exciting and very easy are the cash-cow (low risk, high gain). Mundane but very difficult are probably best avoided (high risk, low gain). Some scientists relish the world-breaking and very difficult (high gain, high risk) probably much the same way as gamblers love the roulette wheel. However, most of us live in the bottom left corner of "not too difficult" and "not too exciting", the low risk low gain world of bread-and-butter work.
I would say that that is fairly true of everyone.
Posted by Martin60 (# 368) on
:
quote:
Originally posted by LeRoc:
quote:
Martin60: We're in the shaded bit of this where the x-axis is energy and the y is complexity as to what's EVER achievable.
So, we can do low-energy complex things and high-energy simple things?
EXACTLY LeRoc. There are NO exceptions. As NASA says: Faster, Better, Cheaper; choose two of the above.
Posted by Martin60 (# 368) on
:
Archimedes' ... complexity eh?
Posted by Russ (# 120) on
:
quote:
Originally posted by Boogie:
We humans need goals and aims or we tend to turn in on each other.
Yes.
We need to be contending with, exercising power over, the universe. As long as the alternative is contending with and exercising power over each other.
Posted by rolyn (# 16840) on
:
When we thought Mars might be inhabited with beings who meant us harm we had a tendency to fight each other .
Now that we know ourselves to be alone in our Solar System, and possibly in the wider Universe, we might possibly be starting to think what's the bloomin point in fighting, controlling, and exerting power over eachother .....Well some of us, in theory at least
Posted by Alan Cresswell (# 31) on
:
quote:
Originally posted by Martin60:
As NASA says: Faster, Better, Cheaper; choose two of the above.
And, if you choose "cheaper" then you only get one choice.
Posted by Martin60 (# 368) on
:
Aye. It'll be crap. Throwing trillions at any and all of the axes won't make fusion or AI or space-faring work. Throwing it up the y-axis IS slowly (z) making inroads in cancer and even dementia by the end of the century. Arthritis? Social justice? Not a chance. Not a hope in hell. Islamic terrorism in response to materialist interference? It all has to be bred out of us.
Posted by Alan Cresswell (# 31) on
:
If not Mars, how about the stars?
OK, not a crewed mission. But, Stephen Hawking thinks we can send small star ships to other star systems within 30 years.
Posted by LeRoc (# 3216) on
:
quote:
Alan Cresswell: But, Stephen Hawking thinks we can send small star ships to other star systems within 30 years.
Phrasing it a bit more clearly, I think he says these ships will take 30 years to get there. This means that they'd be travelling at near-relativistic speeds. I don't think they would have a way of braking when they arrive at α Centauri, so they'd need cameras with very fast shutter times
Did I get it right that these lasers will only need to fire for a couple of minutes?
Posted by Alan Cresswell (# 31) on
:
quote:
Originally posted by LeRoc:
quote:
Alan Cresswell: But, Stephen Hawking thinks we can send small star ships to other star systems within 30 years.
Phrasing it a bit more clearly, I think he says these ships will take 30 years to get there. This means that they'd be travelling at near-relativistic speeds.
4.4 light years, 30 year trip gives an average speed of 15% light speed. Not relativistic, but faster than any other object we've put into space (or, for that matter, any other object that we know of that's not a subatomic particle).
quote:
I don't think they would have a way of braking when they arrive at α Centauri, so they'd need cameras with very fast shutter times
If they could refurl the solar sail once on their way, then unfurling it would give a brake, but it won't be enough to slow the probe very much (unless someone conveniently puts a laser out there for us). If it isn't slowed it will take about 10h to traverse the inner solar system (inside the orbit of Jupiter). If it's solar powered there isn't going to be power to do anything much from further out than that, or probably even that far out. Which is not going to reveal very much from an ultra small aperture camera.
quote:
Did I get it right that these lasers will only need to fire for a couple of minutes?
That's going to depend on the mass of the probe and the power of the laser.
Posted by LeRoc (# 3216) on
:
quote:
Alan Cresswell: [...] 15% light speed. Not relativistic [...]
That's why I said near-relativistic
quote:
Alan Cresswell: That's going to depend on the mass of the probe and the power of the laser.
I've been fiddling around a bit. I started with 1 kg for the chip including a sail and a camera, and a 10 minute laser burst. This means that we'd need a 3 terawatt laser. We have those, but they normally only fire for nanoseconds. The energy required is huge.
Posted by Alan Cresswell (# 31) on
:
Or, turn the equation around. The current most powerful (near) continuous laser is a bit over 1MW. If we assume we can scale that up to 10MW quite easily, how long would we need to fire it to accelerate a 1kg mass of 15% light speed? Assuming 100% efficiency in energy transfer I get 675,000 years!
Posted by LeRoc (# 3216) on
:
quote:
LeRoc: The energy required is huge.
Okay, I did a follow-up calculation. For 1 minute and 45 seconds we turn off all energy in the world and channel that into a 17 TW laser. That would do it
[ETA: Cross-posted.]
[ 13. April 2016, 11:28: Message edited by: LeRoc ]
Posted by Alan Cresswell (# 31) on
:
I think that basically Hawking needs to redo his maths. Making the craft smaller only has a small effect. Reducing the maximum speed would be more effective - but then you're talking centuries to make the journey, not 30 years.
Posted by Dave W. (# 8765) on
:
The NYTimes has an article with more detail and a link to the project's web site.
They're talking about "nanocraft" with a mass of ~1 gram propelled to 0.2c by a mile-wide 100 GW laser array.
Posted by Alan Cresswell (# 31) on
:
If they can build a probe able to collect useful data and transmit it back to Earth with a total mass of 1g (including the solar sail), and they can produce a sustained 100GW laser beam, and they get a conversion efficiency of 10% of laser power to kinetic energy ... then, 3-5* minutes of laser on sail will get them to 0.2c.
* 3 minutes for classical mechanics, I can't be bothered to work out the Relativistic effects considering how big those 'if's' are.
Posted by LeRoc (# 3216) on
:
quote:
Alan Cresswell: * 3 minutes for classical mechanics, I can't be bothered to work out the Relativistic effects considering how big those 'if's' are.
I think the difference at these speeds will only be a couple of per cent at most.
We'd also need to find a way to stop people from using this laser to carve their name in the Moon
(I still think it's good that people think of this kind of thing though.)
Posted by Green Mario (# 18090) on
:
This is a fascinating idea and seems plausible - ditch the need to carry fuel, tiny probe and huge speeds become possible with realistic amounts of energy.
What I don't get is how they will be able to transmit information back from 4 light years away from the transmitter on a 1g probe. Even allowing for improvements in technology there must be physical limits in terms of energy and strength of signal.
The probe sending information back from Pluto had quite a large transmitter - from the looks of the picture, and a decent source of power (well 200W) and because of the distance could only transmit back a very weak signal Pluto Probe; which meant using massive receivers to listen and transferring data slowly.
The nearest star is over 5000 times further away than Pluto, and presumably the signal strength will decrease with the square of distance??
Posted by LeRoc (# 3216) on
:
They're planning on using nuclear decay for power, just as in smoke detectors. I don't know much about what kind of power would be needed; I'll try to look up something about this.
(PS Quickly coming back to lasers, the Titan Laser located at Lawrence Livermore National Laboratory in California for less than a picosecond uses 76 times as much energy as the rest of the world combined. Maybe someone should go and talk with them.)
[ 13. April 2016, 20:36: Message edited by: LeRoc ]
Posted by Lamb Chopped (# 5528) on
:
quote:
Originally posted by LeRoc:
But think about the low-G sex!
I think one would have a tendency to become uncoupled rather easily.
Posted by Martin60 (# 368) on
:
quote:
Originally posted by Alan Cresswell:
If they can build a probe able to collect useful data and transmit it back to Earth with a total mass of 1g (including the solar sail), and they can produce a sustained 100GW laser beam, and they get a conversion efficiency of 10% of laser power to kinetic energy ... then, 3-5* minutes of laser on sail will get them to 0.2c.
* 3 minutes for classical mechanics, I can't be bothered to work out the Relativistic effects considering how big those 'if's' are.
How many 'g' is that? And how much heat? Surely you'd have to ablate a meter thick tungsten disk?
Posted by Alan Cresswell (# 31) on
:
It's 10000-15000g, for 3-5 minutes of acceleration.
For maximum efficiency you want the sail to reflect the laser light without heating. You can have a drive that evaporates when hit by the laser, if you focus the plasma generated it will contribute to the thrust - but, then you have added fuel (and a lot of mass) to the probe.
Posted by Alan Cresswell (# 31) on
:
quote:
Originally posted by Alan Cresswell:
It's 10000-15000g, for 3-5 minutes of acceleration.
Just noticed the NYT article has 60000g. That's higher because a) they envisage only 2mins of acceleration, b) I haven't accounted for the small Relativistic effect and c) as the probe gets further from Earth (which will happen very quickly) the power delivered by the laser will fall off, so the initial acceleration will be much higher. Still, a very high acceleration that will require some engineering (and, that means mass) to ensure the probe doesn't break apart - in particular that it stays attached to the sail.
Posted by Alan Cresswell (# 31) on
:
quote:
Originally posted by LeRoc:
They're planning on using nuclear decay for power, just as in smoke detectors. I don't know much about what kind of power would be needed; I'll try to look up something about this.
The NYT article mentions Americium (the element in smoke detectors), which is an interesting choice of isotope. Conventional RadioThermal Generators (RTGs) such as the one on New Horizons use 238Pu, with an 88 year half life. 241Am has a longer (433y) half life, so you would need 5 times the mass to give the same energy. You gain a power supply that doesn't produce significantly less power over the mission duration (238Pu would decay by 15% over 20y, 241Am by 5%), but in a mass critical application I would go with starting with 20% more 238Pu than needed for the mission end than 5x the mass. 241Am is more readily available and cheaper.
That's before you've worked out how much you need. RTGs surround the isotope with material that is heated by the decay of the isotope, and then a thermo-electric converter. This is simple and reliable technology, but not very efficient (the RTG on New Horizons generates 4000W of heat, 200W of electricity) and heavy (10-20kg). Also, there isn't really any other technology to convert radioactive decay energy to electricity. Which makes it the obvious choice for applications like New Horizons. I have no idea if it's even possible to scale such a generator down to 500mg or less (so it's less than half the mass of the probe), especially if it needs to power an interstellar transmitter.
The New Horizons probe has a ~2m dish and about transmits at about 100W. If a micro-transmitter can produce a focussed signal with a tighter beam than New Horizons, and the amount of data that needs to be transmitted is much less, then a smaller power will work. But, I'd guess at 10W rather than 1W or less. But, let's be generous, and say the probe can operate on 1W (the majority being the transmitter), how big an RTG would it need? Assuming a much higher efficiency than current systems, let's say 5W thermal for 1W electrical, that's an activity of ~5TBq. That comes out to about 8g of 238Pu, or 40g of 241Am. Which is never going to fit in a ~1g probe!
So, from the other end. 250mg of 238Pu will generate 150mW thermal, if they're lucky 50mW electrical. Probably no more than 25mW available for the transmitter ...
-----
my working ...
each decay produces ~5.5MeV alpha particle and we capture the majority of that energy
1eV = 1.6x10^-19 J, 5MeV = 8*10^-13 J (let's call it 10^-12 J)
5W = 5J/s = 5/10^-12 alphas per sec = 5x10^12Bq (5TBq)
decays per sec = N(1-e^-lambda) - where N is number of nuclei
For 238Pu, t1/2 = 88y, 2.8x10^9s
decay constant lambda = ln2/t1/2 = 2.5x10^-10 s-1
thus (1-e^-lambda) = 2.5x10^-10
and, N = 5x10^12/2.5x10^-10 = 2x10^22
mass of each nuclide = 238*1.7x10^-27kg = 4x10^-25 kg
Therefore mass of 238Pu = 2x10^22 * 4x10^-25 = 0.008kg
Posted by LeRoc (# 3216) on
:
Yeah, overall it seems to be nice what-if thinking. (And by all means let them think further about it, who knows in which other ways it might help.)
Posted by LeRoc (# 3216) on
:
quote:
Lamb Chopped: I think one would have a tendency to become uncoupled rather easily.
I understand it involves a lot of elastic bands.
There seems to be an official NASA ban on sex on the ISS. But there have been rumours …
Posted by Martin60 (# 368) on
:
So, it's utter, UTTER twaddle, kid's stuff, hype as bad as the Martian fossil, as useless as hot fusion let alone cold and RF resonant cavity thrusters.
Way out on the x=y line on the hyperbolic paraboloid.
Posted by Doublethink. (# 1984) on
:
The problem with colonisation of another planet, is the fairly inevitable war we will end up having with it when it becomes successful enough to want independence.
Posted by Martin60 (# 368) on
:
60K g needs the robustness of a Luger bullet. A wristwatch can take 5K
Posted by LeRoc (# 3216) on
:
quote:
Doublethink.: The problem with colonisation of another planet, is the fairly inevitable war we will end up having with it when it becomes successful enough to want independence.
The Moon is a Harsh Mistress.
Posted by LeRoc (# 3216) on
:
quote:
Martin60: 60K g needs the robustness of a Luger bullet.
I thought that rifle bullets regularly have an acceleration of over 60,000 g inside the barrel?
Posted by Alan Cresswell (# 31) on
:
10^6 m/s² (wise words at the bottom of that page, BTW), 100000g.
Which does present an alternative to lasers. A gun barrel long enough to sustain that acceleration for 1-2 minutes, with enough explosives to maintain the force pushing the "bullet" (aka nano-star ship). Point and fire.
Posted by LeRoc (# 3216) on
:
quote:
Alan Cresswell: Which does present an alternative to lasers. A gun barrel long enough to sustain that acceleration for 1-2 minutes, with enough explosives to maintain the force pushing the "bullet" (aka nano-star ship). Point and fire.
Now you have me wanting to calculate the recoil
"Alluding to the extent of Florida, a mere peninsula confined between two seas, they pretended that it could never sustain the shock of the discharge, and that it would 'bust up' at the very first shot.
'Very well, let it bust up!' replied the Floridans, with a brevity of the days of ancient Sparta."
Jules Verne, From the Earth to the Moon
Posted by Marvin the Martian (# 4360) on
:
I think we should aim for Europa. Plenty of water there, and even a small possibility of pre-existing life. Far more interesting than a dead red rock.
My other preference would be Titan, which actually has lakes and rivers. Admittedly they're of liquid methane rather than water, but it would at least look familiar to the settlers.
Of course, in both cases we'd need to improve spacesuit heating technology to an unprecedented degree!
Posted by LeRoc (# 3216) on
:
quote:
Marvin the Martian: I think we should aim for Europa. Plenty of water there, and even a small possibility of pre-existing life. Far more interesting than a dead red rock.
This is you, trying to keep us off your planet
I do think living on Europe would mean underwater habitats. Better temperature, and the ice will shield us from Jupiter's radiation.
quote:
Marvin the Martian: My other preference would be Titan, which actually has lakes and rivers. Admittedly they're of liquid methane rather than water, but it would at least look familiar to the settlers.
Some of the artist impressions of Titan look rather good. This is a real picture from the surface BTW.
Added advantage: you'll only need helmets on Titan, no pressure suits.
[ETA: I've just been convinced about Titan ![[Big Grin]](biggrin.gif)
]
[ 14. April 2016, 13:49: Message edited by: LeRoc ]
Posted by Eutychus (# 3081) on
:
quote:
Originally posted by LeRoc:
quote:
Marvin the Martian: I think we should aim for Europa. Plenty of water there, and even a small possibility of pre-existing life. Far more interesting than a dead red rock.
This is you, trying to keep us off your planet
Europa? Attempt no landing there!
Posted by Martin60 (# 368) on
:
quote:
Originally posted by LeRoc:
quote:
Martin60: 60K g needs the robustness of a Luger bullet.
I thought that rifle bullets regularly have an acceleration of over 60,000 g inside the barrel?
I'm sure they do, Alan's figure from the NYT is 60K g.
It CANNOT be done. The barrel length would have to be, ooooh, what a hundred km? In orbit of course. A billion dollars a km. With V-3 / SHARP combustion chambers, etc, etc.
A trillion dollars.
And it's probably a thousand km to get to 0.1c
Ten trillion.
Nope. Ain't gunna happen. Ever. Like fusion. Social justice.
Posted by balaam (# 4543) on
:
quote:
Originally posted by LeRoc:
I do think living on Europe would mean underwater habitats.
Nope. Some of us already live on the surface of Europe ![[Biased]](wink.gif)
Posted by Alan Cresswell (# 31) on
:
An, some consider Europe to be an entirely alien world the other side of (although admittedly not under) water.
Posted by Dave W. (# 8765) on
:
quote:
Originally posted by Alan Cresswell:
10^6 m/s² (wise words at the bottom of that page, BTW), 100000g.
Which does present an alternative to lasers. A gun barrel long enough to sustain that acceleration for 1-2 minutes, with enough explosives to maintain the force pushing the "bullet" (aka nano-star ship). Point and fire.
One minute of acceleration at 60,000g would require a barrel a million kilometers long, which makes the mile-wide laser sound surprisingly sensible by contrast.
Posted by Alan Cresswell (# 31) on
:
Yep, I'd got a similar number. With a similar conclusion. Even though in vacuum higher accelerations would be possible (assuming the probe could take it), it's still a massive engineering project. But, it is just engineering using essentially existing technology - the laser version requires sustained ultra-high power lasers (which we don't have) with adaptive optics (which have only even been used for very small telescopes - well, in comparison to the size of the laser array), and a highly reflective and ultra-lightweight solar sail (which we don't have).
The challenges of a power supply (see my calculations earlier), a transmitter and sensors in a ~1g package able to withstand ultra-high acceleration are common to both launch options.
As Martin has said repeatedly, it's never going to happen.
Posted by Martin60 (# 368) on
:
Far be it from me, but using the 'O' level formulae, where
v = 0.15 c = 45,000 km/s
u = 0
t = 3 m = 180 s
a = (v - u)/t = 250 km/s^2 which /10 m/s^2 = 25,000 g
and
s = ½(v+u) × t = 4,000,000 km barrel length
?
and what do I apply which Lorenz equation to and why?
[ 15. April 2016, 16:36: Message edited by: Martin60 ]
Posted by LeRoc (# 3216) on
:
This is what I was thinking about. The maths are against reaching α Cen, but maybe their efforts can help us discover more about the outer Solar System.
@Martin: your calculations are OK.
Posted by Alan Cresswell (# 31) on
:
quote:
Originally posted by LeRoc:
This is what I was thinking about. The maths are against reaching α Cen, but maybe their efforts can help us discover more about the outer Solar System.
I think the maths are against them make a 1g probe, and against building a laser array big enough to get them to more than 1% light speed. So, if they go ahead then the benefits wouldn't be in the probes they will never launch to those speeds - so, no probes on 3d trips to Pluto. If they actually get something into space they will start with something significantly heavier than 1g, and with a much small laser array to accelerate it. But, if they can get probes with instruments to collect useful data to Pluto in about a year (which needs a mere 200,000 m/s or less than 0.1c) that would in itself be a big step forward in exploring our solar system - that would still need a 10-100MW laser array of a 100-1000g probe, but that could be achieved. It wouldn't take much more to be able to push 10-100kg packages on slow trajectories to Mars, making resupply of a Martian base much cheaper.
But, to do that they would need to do a lot to miniaturise radiation hardened electronics and reduce their power requirements, and powerful and small highly directional transmitters. That will have immediate benefits for everything we launch into space. They will also need to develop RTGs that are an order of magnitude more efficient, and an order of magnitude less massive (for the 1g probe, several orders of magnitude). That will also make conventionally launched space probes lighter and more powerful, and cut the costs of those missions.
Posted by LeRoc (# 3216) on
:
@Alan: Exactly, those are the kind of things I was thinking about. And this is why I think it's good for these people to go ahead with this.
[ 16. April 2016, 06:57: Message edited by: LeRoc ]
Posted by Martin60 (# 368) on
:
That looks feasible up the y=x line Alan. As the space above the hyperbolic paraboloid slowly shrinks.
Posted by Alan Cresswell (# 31) on
:
And, other spin offs from space exploration (without even leaving Earth orbit).
Posted by LeRoc (# 3216) on
:
At least one thing we needn't worry about: mammals can reproduce in space.
Posted by Alan Cresswell (# 31) on
:
Maybe.
Posted by rolyn (# 16840) on
:
Isn't there a thing about our red blood corpuscles changing shape if we spend too long space?
Not sure if this would inhibit reproduction or not.
I think the cryogenically frozen eggs activated by robots is the only realistic option for long distance Space travel. Ultimately delivering humans to another rock on which to play.
Posted by Alan Cresswell (# 31) on
:
There are reductions in the production of red blood cells, and some impact on the immune system. Muscle atrophy and skeletal mass loss can be alleviated to an extent by exercise.
Also, evidence of possible effects on eye sight, and also acceleration of Alzheimers. But, these effects are less certain.
And, that's without considering the impact of high doses of radiation, even without riding out a solar storm.
Posted by Martin60 (# 368) on
:
quote:
Originally posted by rolyn:
Isn't there a thing about our red blood corpuscles changing shape if we spend too long space?
Not sure if this would inhibit reproduction or not.
I think the cryogenically frozen eggs activated by robots is the only realistic option for long distance Space travel. Ultimately delivering humans to another rock on which to play.
Realistic? Uh huh. It's NEVER going to happen.
Posted by LeRoc (# 3216) on
:
Have any of the people who spent 6m+ on the ISS had children afterwards? I couldn't find that so quickly.
Posted by rolyn (# 16840) on
:
quote:
Originally posted by Martin60:
quote:
Originally posted by rolyn:
I think the cryogenically frozen eggs activated by robots is the only realistic option for long distance Space travel. Ultimately delivering humans to another rock on which to play.
Realistic? Uh huh. It's NEVER going to happen.
Are you saying we are doomed to live and die on Earth with no prospect of escape, ever?
I guess this also means we only ever get to speculate as to whether anything like us exists anywhere outside our Solar System and beyond. The same way our ancestors speculated as to whether Mars was inhabited by little green men.
Posted by Martin60 (# 368) on
:
Doomed? To face up to our responsibilities rather than escape them? The promise is if we get it right here, the universe is ours.
Posted by Alan Cresswell (# 31) on
:
quote:
Originally posted by LeRoc:
Have any of the people who spent 6m+ on the ISS had children afterwards? I couldn't find that so quickly.
I tried to look too, and as you note it isn't easy to find that information. Yes, the information about whether they have children is included in their bio's, but not when those children were born.
But, most people in space have already had time to develop a successful career - as a pilot, engineer, scientist, or whatever. By definition, before someone spends the money to put you into space, let alone leave you there for months, they're going to make sure you're the right person to make a contribution to the project. So, in most cases they have been people in their 30s, so probably already have children (or have no intention of having children).
Posted by rolyn (# 16840) on
:
quote:
Originally posted by Martin60:
Doomed? To face up to our responsibilities rather than escape them? The promise is if we get it right here, the universe is ours.
Nice one Martin
Always tempting to try and add something to an ultimate truth such as you've stated. Yet how can something that is ultimate be added too?
The thing we are trapped by is our irrepressible curiosity.
Posted by Martin60 (# 368) on
:
I love this place. I have that too rolyn, but not at the expense of the poor. Like the cretinous hubris of ITER and other obscene vanity projects by the vested interest cabal of politicians and scientists, as in the bandwagon Hawking jumped on outside his very deep and narrow bailiwick. They fool the BBC and people like my wife. 'Oooh that nice Professor Hawking, he's cleverer than you and he says we're going to the stars on a postage stamp for our holidays.'. That nice cuddly Stephen says that nanite is going to eat us all too.
The 'engineer' at the head of the COMPANY touting chipships did have the intellectual honesty to acknowledge the 'difficulties'.
[ 24. April 2016, 09:44: Message edited by: Martin60 ]
Posted by Nicolemr (# 28) on
:
An article on female astronauts' menstrul cycles and reproductive health is here.
Apparently there is no evidence that being in space harms female fertility, but that's not conclusive.
Posted by rolyn (# 16840) on
:
I hate too poo poo motherly instincts but I'm afraid the technology required to cross the mind blowing and colossal distances to reach another habitable planet will not include space bonking and popping out sprogs.
If we did send a few breeding couples out towards the Cosmic beyond then it is likely that those crew members, after several generations, would have mutated into something no longer resembling us on reaching their destination.
.
[ 26. April 2016, 17:49: Message edited by: rolyn ]
Posted by Martin60 (# 368) on
:
You know we won't. Can't. Ever. The technology, like fusion, will never, can never exist.
All we've got to do, is achieve universal justice. And it will be given to us on a plate.
Posted by Alan Cresswell (# 31) on
:
quote:
Originally posted by rolyn:
If we did send a few breeding couples out towards the Cosmic beyond then it is likely that those crew members, after several generations, would have mutated into something no longer resembling us on reaching their destination.
You'd need to send a genetically viable population - probably thousands of couples on the same ship. And, as the journey would take 100s of generations, if not a lot more, then evolution would produce a genetically distinct population. They would still be recognisably human, probably able to walk down the street of any city on earth and not look out of place, but still subtly different. Of course the human population left on Earth will have also undergone some evolution as well, and it would be most unlikely for both groups to undergo parallel evolution.
Posted by LeRoc (# 3216) on
:
So, Elon Musk is planning to go to Mars within two years. Do you think he can pull it off. It would be neat if he could nail the landing.
Posted by Martin60 (# 368) on
:
He ain't. Nobody is. Just another tin can.
Posted by Alan Cresswell (# 31) on
:
quote:
Originally posted by LeRoc:
So, Elon Musk is planning to go to Mars within two years. Do you think he can pull it off. It would be neat if he could nail the landing.
Getting something to Mars is ultimately just a question of enough thrust*. Landing something on the surface of Mars takes a bit more - but, if you have a craft that can descend vertically to land on Earth then you should be able to do the same on Mars.
Can SpaceX develop a version of their launcher (designed to reach low earth orbit) to have enough thrust to go interplanetary? Probably. In two years? Not a chance.
*If you're happy with an inelegant "just add more power" solution. There are some more elegant lower-energy use solutions possible, but will take more time and effort to realise in the short term. Commercial operators rarely look at the more elegant solutions with potential longer-term benefits if there's a quick option.
Posted by Dave W. (# 8765) on
:
Slate has an article on why Musk seems so drawn to set wildly unreasonable expectations.
Posted by LeRoc (# 3216) on
:
quote:
Alan Cresswell: Can SpaceX develop a version of their launcher (designed to reach low earth orbit) to have enough thrust to go interplanetary? Probably. In two years? Not a chance.
I understand that he's basically planning to strap three of his Falcon rockets together.
quote:
Dave W.: Slate has an article on why Musk seems so drawn to set wildly unreasonable expectations.
I like how nuanced this article is.
Posted by Alan Cresswell (# 31) on
:
quote:
Originally posted by LeRoc:
quote:
Alan Cresswell: Can SpaceX develop a version of their launcher (designed to reach low earth orbit) to have enough thrust to go interplanetary? Probably. In two years? Not a chance.
I understand that he's basically planning to strap three of his Falcon rockets together.
Well, that will generate the thrust - and if not he can always go for four. But, life isn't quite that simple. The big issue is going to be controlling each of those rockets to make the whole stable. Plus ramping up production to have enough of them to strap together.
Still not going to happen in two years.
Posted by Dave W. (# 8765) on
:
I think development is a little more advanced than wondering whether they should use 3 or 4.
The first launch of Falcon Heavy is planned for this November; launches for a USAF demo payload and a telecommunications satellite are scheduled for 2017.
Posted by Alan Cresswell (# 31) on
:
They're still not going to be ready to get a shot at Mars in 2018.
Posted by LeRoc (# 3216) on
:
Party pooper Even if it does get delayed a bit, there is still something to be said for this kind of boldness.
Posted by rolyn (# 16840) on
:
"To boldly go" ?
I agree something has to be said for the pioneering spirit which has brought humanity to where it is today.
It still seems a tall order to land a manned craft on a dead an poisonous planet knowing that the occupants cannot return. This is the spirit which drives us to do something, or die trying.
Posted by Martin60 (# 368) on
:
What it should all tell us and should have told me decades ago if I were smart enough, but there again nobody else said it, including here, during my wee phase of arguing God from silence, is that technology will NEVER achieve ANY space opera capability. From silence. The universe - of the eternal infinity of universes - teems with sapience, in our galaxy alone with ten trillion worlds. There is NO interstellar technology. In the universe. No interstellar communication. Nobody is broadcasting. The best we can hope for is to detect biogenic oxygen and signal worlds with it, with radio transmitters many orders of magnitude more powerful than current. Actually economically infeasible ANYWHERE as ... nobody has detected our oxygen and signalled in a thousand years and light years. That's a million stars. Ten thousand. Fifty billion. Requiring petawatt radio and the rest.
Posted by rolyn (# 16840) on
:
And of course a school of thought exists whereby is could be extremely foolish to give away our position in the Cosmos. Undetected means undisturbed, or un-destroyed more to the point.
Thing is, without God can we stand the aloneness ? Maybe we rather something found us, even at the risk of that something being hostile. Or maybe we'd rather jump in a tin can and risk perishing between here and the next habitation rather than simply waiting here for The End
Posted by Dave W. (# 8765) on
:
quote:
Originally posted by Alan Cresswell:
They're still not going to be ready to get a shot at Mars in 2018.
Would you mind sharing the basis for your confidence in this statement?
Posted by Alan Cresswell (# 31) on
:
They haven't yet tested the heavy lift version of their launcher. They're aiming for two satellite launches in 2017. A failure on any of the three planned launches will put the programme back several months at least, and a totally flawless launch is improbable (which is different from a total failure). The possibilities of schedule slippage are substantial. Even if the launches are perfect, there will also be commercial pressures - if they get another commercial satellite launch for a paying customer will they prioritise a Mars launch over cash in the bank?
If all goes well then they may be in position to launch for Mars. But, they'll be on a tight schedule. The 2018 launch window is 30th April, after that the next window is June 2020. If they were aiming for 2020 I might say it was challenging but feasible, 2018 just has far too many steps that need to get passed without any sort of hitch.
Posted by Martin60 (# 368) on
:
quote:
Originally posted by rolyn:
And of course a school of thought exists whereby is could be extremely foolish to give away our position in the Cosmos. Undetected means undisturbed, or un-destroyed more to the point.
Thing is, without God can we stand the aloneness ? Maybe we rather something found us, even at the risk of that something being hostile. Or maybe we'd rather jump in a tin can and risk perishing between here and the next habitation rather than simply waiting here for The End
Nobody CAN do any disturbing or destroying, even tho' they're there, even if they wanted to. The only disturbance will be to our egos and theologies if we ever detect biogenic oxygen.
Posted by Dave W. (# 8765) on
:
SpaceX's record of Falcon 9 launches was pretty good from the start. One could argue that the re-use of well-understood systems makes the Falcon Heavy less risky than the Falcon 9 was at a similar stage of development, so it should require less testing. The second stages are identical, and the Falcon Heavy first stage is just a multiple of the Falcon 9 first stage - all components they have a lot of experience with - and operating rockets bundled side-by-side is hardly novel.
(In addition, you may think early launch successes are improbable, but the people paying for the satellites apparently don't.)
I don't really see a good basis for saying there's "not a chance" the launcher will be ready. I haven't heard anything about what the Mars payload is supposed to be, but it may be that the launcher is the least risky thing about the whole project. Experience has shown that it's a lot easier to get something headed towards Mars than it is to actually get it on Mars.
Posted by Alan Cresswell (# 31) on
:
quote:
Originally posted by Dave W.:
(In addition, you may think early launch successes are improbable, but the people paying for the satellites apparently don't.)
At present, according to the Wiki article, that's defence payload (which is also listed as a second test launch) and one satellite. That's not a ringing endorsement, and as neither launch will be time critical there's unlikely to be massive problems with a six month delay, whereas a few months delay will result in missing the Mars launch window for 2018.
The SpaceX Mars lander is called Red Dragon according to Wikipedia, and is a modified Dragon V2 capsule - the Dragon V2 is due to start trials this year (so, another component of a Mars mission that needs to be ready on a tight timescale), and will be equipped with a single instrument to drill for water underneath the lander (that part is low risk, relative to other parts of any space mission).
Posted by Baptist Trainfan (# 15128) on
:
quote:
Originally posted by Dave W.:
The Falcon Heavy first stage is just a multiple of the Falcon 9 first stage - all components they have a lot of experience with - and operating rockets bundled side-by-side is hardly novel.
Hmm ... one of the main reasons for the failure of the Soviet N-1 was because it used clusters of engines which, together, did not function as expected. However, there were about 30 of them so it is a different scenario to the Falcon.
Posted by Alan Cresswell (# 31) on
:
Operating multiple engines is not as simple as a single engine. Slight differences in thrust between the engines can create navigational issues that need to be corrected. And, the exhaust gases will interfere to create turbulance behind the engine that affect performance. But, several launch vehicles use multiple engines - either multiple main engines or boosters like the Shuttle.
So, although there are technical challenges that take time to resolve it's not rocket science. Oh, wait. Yes it is.
Posted by Dave W. (# 8765) on
:
quote:
Originally posted by Alan Cresswell:
Operating multiple engines is not as simple as a single engine. Slight differences in thrust between the engines can create navigational issues that need to be corrected. And, the exhaust gases will interfere to create turbulance behind the engine that affect performance. But, several launch vehicles use multiple engines - either multiple main engines or boosters like the Shuttle.
I get the impression that you're just thinking of things off the top of your head - plausible-sounding reasons why what they're doing is hard. Well, yes - but they know that too, and they launch rockets for a living, so such invocations of difficulty don't carry much weight. Without any particular expertise, or reference to some informed source, you shouldn't really expect your confident-sounding estimates of the likelihood of success to be convincing.
For my part, I suspect the most likely sources of potential trouble will be the less noticeable and sexy pieces of hardware that they'll be flying with for the first time, like the interconnects between the neighboring cores, or the mechanism for separating the boosters from the center core. "Slight differences in thrust" probably won't be a major concern - that's what feedback control systems are for - and wouldn't raise "navigational" issues in any case.
(Besides - you may not have noticed, but they're already operating nine engines in parallel.) quote:
So, although there are technical challenges that take time to resolve it's not rocket science. Oh, wait. Yes it is.
Spare me.
Posted by Martin60 (# 368) on
:
The answer to Fermi is of course that they're everywhere, at least every 10K LY, every half a billion worlds, but all experience the same socio-economic constraints.
Posted by Alan Cresswell (# 31) on
:
A rocket is a complex piece of machinery. As you say, lots of little interconnecting bits and pieces. And, when they have ignition everything has to work properly (unless you build in multiple levels of redundancy - and that increases cost). If an engine misfires it can send the rocket wildly off-course, or result in the destruction of the whole thing. If the guidance and control systems fail to work then the rocket doesn't put the payload into the correct orbit, or maybe doesn't reach orbit at all. Leaks in fuel lines, thousands of circuits that can fail ... it's a substantial list. A rocket is a bomb that explodes in a controlled manner - too much control and the rocket doesn't lift off, too little and it reverts to it's natural state.
No one has denied that preparing and testing an as-yet unflown rocket for a launch in less than 24 months isn't a challenge. Nor is preparing and testing the Dragon V2 payload. It's a massive challenge, and a very tight deadline. Deadlines have the habit of focussing minds and making the impossible an astounding achievement. They can also result in corners getting cut, details missed, mistakes made. And, with the margin for error practically zero that can very easily end up in a rocket spread all over the place.
Do you honestly think that SpaceX can get every single part of the heavy lift Falcon, and it's payload, right first time? That you don't think there will be dozens of components that take a month or two longer to get right that than the ambitious timetable allows for? Do you expect the first test launch to take place November this year? And, for it to happen without identifying any issues that will take some time to remedy? Do you expect that a second launch a mere four months later can be prepared on that timescale, implementing whatever adjustments the first launch show are necessary? How many months of delay are allowed in that schedule for a May 2018 launch?
Musk wants two firsts - the first private mission to Mars, and the first major engineering project completed on schedule. I think he's probably ahead of the field to achieve the first, it wouldn't surprise me if he launched in the 2020 window. But, on the second Murphy still rules.
Posted by Baptist Trainfan (# 15128) on
:
I read somewhere that the Saturn V rocket had 6 million individual parts. Just a 0.1% failure rate meant the failure of 6000 pieces. So it had to be much, much lower.
Conversely, the Black Knight rocket which put the Prospero satellite into orbit had a lot of the redundancy taken out as it was believed that simplicity aided reliability as well as saving weight. It's still the only all-British satellite launch.
[ 09. May 2016, 14:47: Message edited by: Baptist Trainfan ]
Posted by Martin60 (# 368) on
:
Aye, 6 million of which 2 million were moving. So the failure of only 3 missions out of 16 is pretty impressive.
Posted by mark_in_manchester (# 15978) on
:
quote:
Conversely, the Black Knight rocket...
There's a good chapter on this in Francis Spufford (of 'Unapologetic' fame)'s 'Backroom Boys'.
Posted by Graven Image (# 8755) on
:
As we are messing up the planet we are living on with wars, trash, warming, destroying the land with strip mining, and fracking, chemicals and more we should not be allowed to leave here and go any other place until we can prove to have wised up.
Posted by Dave W. (# 8765) on
:
quote:
Originally posted by Alan Cresswell:
[more emphatic statements about how space flight is hard]
Yes, thank you, I get the picture. So far you haven't said anything to convince me that you know more about this than I do. quote:
Do you honestly think that SpaceX can get every single part of the heavy lift Falcon, and it's payload, right first time? That you don't think there will be dozens of components that take a month or two longer to get right that than the ambitious timetable allows for? Do you expect the first test launch to take place November this year? And, for it to happen without identifying any issues that will take some time to remedy? Do you expect that a second launch a mere four months later can be prepared on that timescale, implementing whatever adjustments the first launch show are necessary? How many months of delay are allowed in that schedule for a May 2018 launch?
As I noted before, the very first launch of the Falcon 9 was a success, and that was arguably riskier than the Falcon Heavy, which is mostly more of the same.
I don't know whether they'll be able to do it or not, but you haven't provided any particular grounds for skepticism besides your personal incredulity, which as far as I can tell is not especially informed by familiarity with this program in particular or launch vehicle development in general.
My skepticism of your skepticism isn't invulnerable - maybe there were massive delays in the Falcon 9 development schedule, now forgotten in the haze of celebration, or maybe SpaceX is hopelessly behind in the manufacture of critical self-sealing stem bolts. I don't know - but then, neither do you (apparently.)
(You needn't feel obliged to continue this tangent - I won't think less of you for stopping.)
Posted by LeRoc (# 3216) on
:
[QUOTEGraven Image: As we are messing up the planet we are living on with wars, trash, warming, destroying the land with strip mining, and fracking, chemicals and more we should not be allowed to leave here and go any other place until we can prove to have wised up.[/QUOTE]You're about the fourth saying this on this thread, and none of you have reacted to the answers that were given to this. Could one of you please tell me why it matters if we mess up a lifeless planet?
Posted by Alan Cresswell (# 31) on
:
quote:
Originally posted by Dave W.:
My skepticism of your skepticism isn't invulnerable - maybe there were massive delays in the Falcon 9 development schedule, now forgotten in the haze of celebration
You're right I'm not an expert on the details - nuclear physics not rocket science is my area of expertise. But, I can read Wikipedia the same as anyone
quote:
The original NASA COTS contract called for the first demonstration flight of Falcon in September 2008, and completion of all three demonstration missions by September 2009 ...
The first launch attempt occurred at 1:30 pm EDT on Friday, June 4, 2010 (1730 UTC). The launch was aborted shortly after ignition, and the rocket successfully went through a failsafe abort. Ground crews were able to recycle the rocket, and successfully launched it at 2:45 pm EDT (1845 UTC) the same day.
The second Falcon 9 launch, and first COTS demo flight, lifted off on December 8, 2010.
Original schedule: first flight in September 2008 with three more by September 2009.
Actual performance: first flight June 2010 (21 months behind schedule, 9 months after the three demo missions were supposed to have flown), and that was not without a hitch.
And, it took 6 months to get the second launch off the ground, which is significantly slower than the original 3 in a year schedule.
If SpaceX does by some miracle actually pull a 2018 launch off then I'll be among those toasting a remarkable achievement. Even more so if they then succeed in getting Red Dragon onto the surface of Mars. I'm not going to bet on it though. I could probably get very good odds form a bookie for a 2018 Mars launch, but I would only be giving the bookie some of my money. I'd do better on the Lottery, and that's a mugs game as well.
I believe that we will get people onto the surface of Mars, I may even live to see it happen. But, I don't think it will happen by a SpaceX or Mars Direct rush job. It will happen through careful development of technology, by small intermediate steps (back to the Moon being among them) and probably development of a more efficient transit method than simply strapping the biggest rocket we can manage under the capsule.
Posted by Dave W. (# 8765) on
:
quote:
Originally posted by Alan Cresswell:
quote:
The original NASA COTS contract called for the first demonstration flight of Falcon in September 2008, and completion of all three demonstration missions by September 2009 ...
The first launch attempt occurred at 1:30 pm EDT on Friday, June 4, 2010 (1730 UTC). The launch was aborted shortly after ignition, and the rocket successfully went through a failsafe abort. Ground crews were able to recycle the rocket, and successfully launched it at 2:45 pm EDT (1845 UTC) the same day.
The second Falcon 9 launch, and first COTS demo flight, lifted off on December 8, 2010.
Original schedule: first flight in September 2008 with three more by September 2009.
Actual performance: first flight June 2010 (21 months behind schedule, 9 months after the three demo missions were supposed to have flown), and that was not without a hitch.
And, it took 6 months to get the second launch off the ground, which is significantly slower than the original 3 in a year schedule.
Thanks, Alan - that seems a more convincing argument. (And since I suggested early customers amounted to a vote of confidence, I should probably note this article as evidence against optimism.) quote:
I believe that we will get people onto the surface of Mars, I may even live to see it happen. But, I don't think it will happen by a SpaceX or Mars Direct rush job. It will happen through careful development of technology, by small intermediate steps (back to the Moon being among them) and probably development of a more efficient transit method than simply strapping the biggest rocket we can manage under the capsule.
What do you mean by a more efficient transit method? Big rockets have the distinct virtue of having delivered payloads to Mars before; they seem the most likely choice for the first mission with people.
And if Mars is the eventual goal, going back to the moon seems like a pointless detour, your previous post on the topic notwithstanding. I don't know of any reason to think that low-G effects aren't bounded by those of 1-G and 0-G, we hardly need to go there to study the effects of isolation, and predicating a Mars mission on the development of a lunar mining industry seems like an elaborate way of saying we're really not interested in going to Mars.
Posted by LeRoc (# 3216) on
:
When it comes to colonisation, I do see the merits of going back to the Moon first.
Posted by Alan Cresswell (# 31) on
:
quote:
Originally posted by Dave W.:
What do you mean by a more efficient transit method?
An example might be an Aldrin Cycler. You need a big rocket to get the cycler running, but once it's up and running you have a single big ship running non-stop on a long orbit carrying the reactor, life support, shielding etc needed for the transits between Earth and Mars then all you need are smaller transfer ships to get from Earth orbit to intercept the cycler, and from the cycler to Mars orbit (vice versa for the return trip). Small ships mean a lot less propellant to get them up to speed.
The first few Mars trips will probably mean launching a section of the cycler along with the Mars lander, so the savings for those will be minimal but in the longer term the savings can be substantial.
Posted by Alan Cresswell (# 31) on
:
and, re: the Moon. One of the biggest challenges to efficient interplanetary travel is getting fuel into space for the trip. If it's possible to extract fuel from the Moon, then a base there will make fuelling Mars bound ships much cheaper.
The other viable technology for getting fuel (and other non-fragile equipment and supplies) into LEO suffers from political bad press after Gerald Bull decided to get help from a pro-western government in the Middle East. And, then found that pro-Western is not the same as nice and got himself assassinated shortly before the Wests best friend in the region turned in to public enemy number 1.
Posted by LeRoc (# 3216) on
:
I like this cycler. I hadn't heard about it before.
Posted by Martin60 (# 368) on
:
Why bother with Lunar fuel when you can kick them up the arse with this. 1st link
Posted by Alan Cresswell (# 31) on
:
Because you still need to get the fuel into orbit - whether that's chemical or nuclear.
Posted by Martin60 (# 368) on
:
Twenty million times less for nuclear fission, no? One hundred and forty million times less for fusion? Kick 'em up the arse.
Posted by Dave W. (# 8765) on
:
What will be the reason behind all these trips to Mars, do you imagine? I can see the motivation behind an exploratory mission, or two or three, but that hardly seems enough to justify contemplating setting up an entire lunar mining industry. As for the cycler - I suppose building a 750 mile bridge from Tierra del Fuego to Trinity Peninsula might make getting to Antarctica more efficient, but I really don't think the demand would justify it.
And I doubt Gerald Bull's questionable associations would matter in the slightest as far as the acceptability of his proposed technology is concerned - just ask SS-Sturmbahnfuehrer von Braun.
Posted by Alan Cresswell (# 31) on
:
quote:
Originally posted by Dave W.:
What will be the reason behind all these trips to Mars, do you imagine?
As you note, exploration doesn't require many human expeditions - robotic missions are cheaper, safer, provide similar scientific value. But, are less "sexy" than human boots on Martian soil. The scientific value of repeated human visits to extra-terrestrial locations is clearly demonstrated by the lack of visits to the Moon after the Apollo missions.
The only real reason for lots of missions to Mars, where a cycler becomes incredibly beneficial, is to establish a permanent human presence there. I suppose the fundamental question is there a reason for a permanent human presence on Mars? If there is then that justifies the lunar fuel production, the cycler and so on.
Posted by Martin60 (# 368) on
:
Which it never will. Ever. Naming your boats after Ian M. Banks' won't help.
Posted by LeRoc (# 3216) on
:
quote:
Martin60: Naming your boats after Ian M. Banks' won't help.
I know a better way to find a name for a boat.
Posted by Doc Tor (# 9748) on
:
We can't name them all Spacey McSpaceface...
Posted by Eutychus (# 3081) on
:
How about GSS Daring? GSS Audacity? GSS Suicidal Insanity?
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