While I understand what you are saying you have to accept that this is part of the human condition. If everyone in America gave up a meal a week I bet those people could eat comfortably. It isn’t going to happen. People are very protective over what they preceive to be their earnings and they don’t appreciate being guilt-tripped on what they should spend it on.
Anyway, I imagine you are right Stranger, we’d have to get some fairly useful robots into space first to establish a habitat, then work on getting humans up there. Generation ships don’t seem feasible to me and it is kind of freaky to think we would have no way of anything close to quick communication with these people after they arrived at their destination.
It is a bit old, but The High Frontier is available as an e-Book;
This book gives a blueprint for colonising the solar system, but it would need to be updated to emphasise robotic developments. As robots get more capable then the potential for exploiting the solar system increases, but eventually we may get to a point where humans just won’t be needed out there at all.
Why is it that you give space treatment special scrutiny over this issue? You’d think people with this attitutde thought we spent 30% of the world’s GDP on space exploration, and not something like 0.00000001%.
If we did decide to lift the world’s poorest people, why do those resources need to come from the space program? There are a thousand things more extravagent, more wasteful, and less useful. Everything from wars that cause the loss of untold life and treasure to running your air conditioning a few degrees cooler than need be is a bigger expenditure than the entirety of human space exploration, and yet only when it comes to space exploration do you get this “but there are people with shitty lives out there!” attitude.
Space exploration is almost certainly a net economic gain for the world. It has given us huge legs up in communications, navigation, earth sciences, etc. It has inspired people to beome scientists and engineers which is no small economic impact. It has spun off into all sorts of useful technologies. For the paltry amount we invest in it, the world gets more out of it.
And there is a cultural and historical factor. When civilizations turn inwards, when they neglect to explore and become focused on maintaining what they have, they shrivel and die. There’s something about the human condition that requires us to be explorers, to seek knowledge, to expand our known world, in order to keep us healthy.
I find this attitude bizarrely common. I’m guessing there’s some sort of anti-intellectual component to it. “Oh, you pointy headed scientists are wasting your time on stuff I can’t even understand while people starve!” as if those two things had anything to do with each other.
The issue would be the same for plenty of other expenses. Building a road is less urgent than feeding the starving and curing the ill. Military expenses should obviously be reduced to zero. Research that isn’t aimed at a short-term, tangible result defunded. The idea of funding art or museums should be laughed at, and so on…
So? That’s for the exact same reason that Americans landed on the moon. Or that anybody flew a spacecraft, for that matter. Who cares what their motives are?
Human space exploration has been abandoned. Many, many people regret it. Whatever the motives of China, they bring a hope that someday we’ll finally have this base on the moon, or see humans landing on Mars, or something. That’s obviously exciting.
Besides, the fact that China currently uses existing technology doesn’t mean that it won’t end up soon on the forefront of space exploration in general and producing innovating, ground-breaking new technologies for it. I certainly expect that, for my part.
I don’t think it’s a veneration of the Chinese space program as a shining example of advanced technology. I think, instead, that the attention paid to the program is a desperate attempt to prick the pride and ego of the western world to build a spacefaring community instead of the Chinese.
[QUOTE=Stranger On A Train]
This will not support any kind of interstellar transit, which would require suspension of catabolism over a period of centuries or longer.
[/QUOTE]
You were the one who brought up interstellar travel, not me. I’m merely pointing out that those clueless guys at NASA think that there might be something to using torpor/hibernation for, say, a Mars transit…and that this is far from the fantasy or pie in the sky you seemed to be making it out to be, since the technique is already in use here on Earth.
[QUOTE=snowthx]
^ This. IMHO, we have a lot more pressing matters to contend with on Earth and resources should be focused there instead of baubles in space. The problems are not as fun and sexy as space exporation, however.
[/QUOTE]
Do you feel the same about all scientific research that doesn’t have a clearly defined focus on the issues here on Earth? Or any activity that isn’t focused strictly on problems here on Earth?
Your definition of a ‘pipe-dream’ must be different than mine. I mean, we have ALREADY shown that travel to another planetary body is possible (unless you are one of those Moon Hoaxer types), and have done extensive unmanned probes to many of the planets and even some of the more interesting moons in the solar system. This isn’t science fiction, it’s fact. There is nothing (except maybe the price) stopping us (humanity) from a manned mission to Mars. And this thread was about more than manned travel…it was about new tech that enables us to better understand and explore not only the solar system but the universe at large. I have to scratch my head at dopers on this subject. We have done so much cool stuff in space in the last 20 years, and the next look to be even more amazing. We have discovered extra-solar planets when no one thought they could do that. We have discovered super-massive black holes at the centers of most of the galaxies, and narrowed down what something like a quasar is…all things that 20 or 30 years ago people would have thought impossible or at least highly unlikely. We’ve sent probes out to land on remote planets and bring back science, landed on asteroids and now a comet, put up more and more powerful space born telescopes and detection missions and are constantly pushing the boundaries of what we know and testing the theories of theoretical physics that once seemed immutable.
I don’t see a pressing need, or really any need at all, to put anything non-robotic in space. This conviction that humanity must “reach for the stars” is just another variety of woo.
I don’t think you’re talking about the same thing. I doin’t recall Stranger saying that using torpor to reduce food/water requirements for a Mars trip is fantasy.
What he actually said is this:
Putting someone in a state of torpor so they don’t eat or drink as much has nothing to do with any of this. Torpor is not hibernation for the purposes he’s talking about, because it doesn’t stop the aging process. Therefore, it can’t be used to allow someone to make an interstellar trip and be alive when they get to their destination.
The thermodynamic problem he’s talking about comes from the fact that a generational ship will be generating heat inside a volume, while only being able to radiate it away through surface area. That, and the truly enormous energy requirements to accelerate a huge generational ship to any reasonable fraction of the speed of light means that even a tiny percentage of waste heat would be impossible to deal with. When you are in the vacuum of space, getting rid of waste heat is not a trivial issue.
The other problem is that such a ship would be in transit for hundreds or even thousands of years, and we simply don’t have anywhere near the technology that would allow us to build a complicated ship that could reasonably be expected to survive that long. A viable generation ship would require thousands of people and would be incredibly huge. Accelerating that to any significant fraction of the speed of light is something we just don’t know how to do.
[QUOTE=Sam Stone]
I don’t think you’re talking about the same thing. I doin’t recall Stranger saying that using torpor to reduce food/water requirements for a Mars trip is fantasy.
[/QUOTE]
And I said this:
The word ‘interstellar’ never came up at all. He then dismissed this as ‘demonstrably facile’, which it isn’t. Granted, he was talking about interstellar uses, but I WASN’T.
This thread was about potential real world technologies that could be game changers in space exploration in the next 50 years and wasn’t fixated either on pie in the sky or on just human exploration. But it is the same dismissal of all things space on this board and jumped immediately into strawman arguments about going to the stars and other such bullshit. There is real, tangible hard science being done and real progress being made in space exploration today with unbelievable results and new real world technologies being worked on by both private companies and various governments in the quest to explore and learn more about the universe outside of the Earth (as well as the Earth itself) that are ground breaking and envelop pushing…and THAT was what I was asking.
Getting back to some breakthroughs that could change the game in space…
There are some that are very close to reality now. The closest is SpaceX’s reusable rocket technology. One of the reasons space access is so expensive is because we have to throw away 90% of the vehicle every time we launch. If we had to destroy a 747 every time you flew across the ocean, airline travel would be hideously expensive too.
SpaceX plans to change that by returning the rocket pieces back to the launching pad under their own power. They have been demonstrating this capability for several years now, and have ‘soft landed’ the 1st stage booster on the ocean to prove it’s feasibility. They are now building an ocean-based platform and plan to soft-land a rocket on it soon.
A reusable rocket will drop the price of space launch by as much as 90%. SpaceX thinks they can eventually lower the cost of a Falcon 9 launch from 56 million today to 5-7 million for a reusable version. If so, that’s a massive breakthrough in the cost of space access.
SpaceX is also currently working on the design for the Mars Colonial Transporter, a super-heavy lift reusable rocket system that could send 100 tons into Mars orbit on a single launch, or take 100 people at a time to Mars. This sounds like fanciful science fiction, but so did a lot of other things SpaceX has already accomplished. And Musk plans to fly this thing ‘as early as’ 2020 - only six years away. More realistically, I’d bet on 10 years. But that’s still very near term as these things go.
Another game-changer for human space settlement could be Robotic 3D printing of structures using native materials. The idea is to use the lunar regolith as a 3D printing material - sent a robot printer to the moon, and have it 3D print habitats right out of the lunar soil. When astronauts arrive, they would have an entire moonbase facility waiting for them. This technology is being worked on now.
BTW, if we want a permanent off-earth settlement - even a self-sustaining one - the moon is a much better choice than Mars. Mars is an incredibly hostile environment, and its atmosphere doesn’t help much. Its soil is full of reactive perchlorates that are toxic to humans. It makes up .5% to 1% of the Mars soil, and would be present in the dust storms that are a constant feature on the planet. With the thin atmosphere blowing it everywhere, it would be a constant and extremely dangerous problem.
Mars also offers no protection from cosmic rays, which would be a constant danger to colonists. The atmosphere is far too thin to be useful, but thick enough to be a constant problem with dust contamination, heat loss, etc.
Mars is also so far away that accessing it will be extremely expensive and time consuming. So why not colonize the moon? The moon is thought to have many empty lava tubes below the surface. Seal one, put airlocks in it for entry/egress, pressurize it, and you might be able to build a habitat for thousands of people, safe from cosmic rays and micrometeorite impacts. With solar panels or a compact nuclear module on the surface for power and hydroponic gardening below, you could make it earth-like and self-sustaining.
The moon is also close enough that people can return home after being there for a while, and resupply from Earth would be a lot easier. Close also means easier radio and data communications - internet access would be possible for moon colonists, although the gaming lag would be awful (-:
Not having an atmosphere makes it more useful for science and engineering than Mars would be. Not having to deal with atmospheric effects would make construction simpler.
I think you two are talking past each other. I thought Stranger was simply firing a pre-emptive shot across the bow with regards to generation ships and interstellar travel. In the same message he directly answered your OP with lots of upcoming near-term technologies that would change the game in space.
I don’t think that’s fair. Stranger on a Train is far from being someone who ‘dismisses all things space’. As an actual working scientist, he’s probably just tired of science/engineering discussions devolving into fantasies and science fiction ideas being quoted as reasonable future tech. So on the one hand you may have some people ‘dismissing all things space’, but on the other you also get people talking about ‘warp drives’, wormholes, suspended animation, and generation starships as being reasonable topics for discussion in any thread about space travel.
Yeah, I think we all got that and Stranger responded directly to your OP, as did I. And you’re right - big changes are coming.
Thank you for the on topic post, Sam.
I pretty much agree with everything you’ve said (there are also some good breakthroughs being done in plasmas as well as micro exploration space craft that I’d bring up as well), but I’m not sure about this part:
I think Mars is a much more scientifically significant body for exploration than the moon. I don’t really see colonization as something we could realistically be looking at in the next 50 years (if ever), but a real scientific study of Mars (robotic and manned) I think will but much more scientifically meaningful than the moon, since there is the real possibility of discovering fossils or evidence of early life, as well as much more geologically interesting than the moon. The moon I think would be a better test bed for experimentation with a permanent settlement a la the scientific enclaves in Antarctica, as well as the possibility of economic exploitation of minerals and H3 in the future.
I wasn’t thinking of scientific study of the moon itself (although there’s still much to be learned there), but using the moon as a platform for experiments in vacuum, for large telescopes, for low-gravity experiments, etc. The lack of an atmosphere means you don’t have to worry about erosion or wind loading, and can therefore build simpler and lighter structures. The moon is geologically dead, so you don’t have to worry about moonquakes or volcanic eruptions, either. The moon has plenty of water - billions of metric tons of water ice at least. And it may be more accessible on the moon than on Mars - existing in large quantities on the surface of darkened craters, perhaps in sheets below the surface in many places, or as ice particles spread through the regolith. We’ve detected traces of water all over the Moon, but especially around the poles.
With water you can make air, and you can make rocket fuel. With Regolith and heat, you can make a 3D printing material. without an atmosphere, solar power is more effective and with nothing to disturb it solar panels can be made incredibly light and flimsy.
But most importantly, access to the moon is orders of magnitude easier.
A generation ship has less of a problem with waste heat than a space habitat in the Solar System, because it is not in direct sunlight. Designs such as the Stanford Torus have only moderately large radiator surfaces to emit their waste heat, despite being in sunlight; a generation ship would only be bathed in cosmic background temperatures, so would need smaller radiators.
The idea of a generation ship is that the craft travels at a small percentage of light speed, thereby reducing the amount of fuel required considerably. Halve the speed and the fuel requirement (and heat generation during acceleration) is reduced geometrically.
Not today, we don’t; but it is not unreasonable to expect that we will eventually. Don’t forget that there are people on this ship, who can fettle things that go wrong.
As pointed out above the ship needs only to travel at a very small fraction of light speed, if it can be maintained for many thousands of years. And don’t forget that the concept of a ‘breeding population’ need not apply to a generation ship, since they could carry stored or digitised DNA with them. The crew need only be a couple of dozen, or even fewer.
I should point out that I’m not a fan of generation ships, mostly because of something called the Wait Equation; if you launch a very slow ship a very long way there is a very good chance it will be overtaken by a slightly faster ship a few decades or centuries later.
http://www.jbis.org.uk/paper.php?p=2006.59.239
When I said a ‘significant fraction of the speed of light’, I meant as compared to the speed of chemical rockets today. I wouldn’t suggest that a generation ship would go even 20% of the speed of light - I was thinking more like 1% of C - enough that you could get out to the closest potentially habitable star systems with travel times on the order of a thousand years.
I think most people greatly underestimate the energy required to accelerate a mass to that kind of speed - especially a mass large enough to house a self-sustaining multi-generational civilization.
If they have the parts, and the energy, and the know-how passed down through generations. And if nothing breaks that intrinsically can’t be repaired on-site, and if the failure isn’t catastrophic.
Actually, if you’re talking about thousands of years of travel, you’d never send a colony ship. You’d send a much smaller automated ship stocked with frozen embryos or eggs and sperm, and then hatch your population when you get there. There’s absolutely no reason to keep humans alive as basically cattle for a hundred generations, just so that you have some people alive when you get to your destination.
But even 1% of the speed of light is a fantastically large number. That’s about 3,000 km/s. The fastest spacecraft we’ve ever launched, Voyager 1, is moving away from the sun at about 17 km/s. Even though it only weighs about 700 kg, it took a Titan IIIE rocket to launch it at that speed. 1% the speed of light is 176 times that velocity. And because of the rocket equation, you need far, far more than 176 times the fuel to get something up to that speed.
Project Daedelus, for example, was a paper design for an unmanned interstellar probe. It had a 450 tonne payload, and required 50,000 tonnes of nuclear fuel to get it up to 12% of the speed of light using a hypothetical highly efficient fusion rocket engine. It wasn’t intended to ever slow down, so if you wanted to actually stop at a star system, the max attainable speed would have been half that.
To put that into perspective, A Saturn V rocket, the biggest lifter we’ve ever had, could lift about 118 tonnes into low-earth orbit. So our interstellar ship with a 500 ton payload would have required at least 425 Saturn V launches to get the mass into space. Going 10 light years in that ship would take 166 years, not counting the time required to accelerate and decelerate. So of course we couldn’t do that, and the idea was that the fuel for the trip would be harvested from the atmosphere of Jupiter (Helium-3). Something we have no idea how to do.
Now compare that 450 tonne payload with the hundreds of thousands of tonnes required for a generational starship (the Stanford Torus was supposed to weigh something like 11 million tonnes). Assume we could build a generational starship 1/10 that size, you’re still taking about a ship 20 times as big as Daedelus, requiring millions of tonnes of Helium-3 fuel. A ship that size would have to almost certainly be made from materials already in space (perhaps a hollowed out asteroid), fueled from Jupiter’s atmosphere, etc. We won’t have any capability to even begin construction of something like that for at least a hundred years and maybe hundreds of years, and it would be by far the largest project mankind ever attempted.
A ship like that would take about 4,000 years to make it to Gliese 581, which is probably the closest candidate star system we know of today. Do you really think mankind would put that kind of effort into a colony ship with a very low chance of success, and which wouldn’t even arrive at its destination until a period of time elapsed equal to the time between the construction of the Pyramids and today? Why would we do that?
Humans are probably going to be better caretakers at improvising solutions and fixes to the problems that will crop up. Maybe not by the time this idea becomes viable. But while it certainly enhances the practicality of the trip significantly not to have anyone awake, there are certainly reasons that it would be beneficial.
I agree with all your points, Sam Stone, which may surprise yo. I’m no great fan of the generation ship concept, as I’ve said. However I’m slightly more optimistic about the reduced version, sometimes called the ‘quasi-generation ship’ which I mentioned above; this could be quite a small vessel, with only a couple of dozen people on board and a vast store of DNA stored in data form. By the time we are ready to launch such a ship there will almost certainly have been significant advances in biotechnology, enough that we could get a vast diversity of genetics into a tiny data store. Having real humans on the ship would help with the establishment of a colony at the other end, avoiding the necessity for humans with robot mothers.
Maybe biotechnology could allow the crew to live so long that they could get there in a single lifetime, thousands of years long. The biggest problem might be that the crew would go mad at some time over the millennia, or lose interest in the colonisation project.
Perhaps Stranger is referring to the trouble with entropy on such a ship. After thousands of years a closed system might degrade so much as to be unrecognisable. To prevent this sort of decay would require energy - and growing food for living crewmembers would also require energy - lots of it. There must be a cost-benefit calculation that compares the amount of energy that is required to get the ship up to speed with the energy required to keep the ship and its contents functioning and recognisable; if the second one exceeds the first, then it is advantageous to expend more energy on acceleration.
How can they dwarf anything we could extract on earth? What kind of exploitable celestial body has more resources than earth? There may very well be but all the places I can think of are smaller than earth.
How do you send bulk materials down to earth cheaply without having them burn up?
What kind of manufacturing is so polluting and poses such terrestrial issues that it could eventually be cheaper to do it in space than underground, in the desert or Siberia/Northern Canada?