Moving asteroids around wouldn't be particularly expensive. Especially the ones already passing near Earth. Somewhat dangerous, however--would you really want people aiming asteroids into Earth orbit?
It is sci fi in the current climate of the world. As such optimistic space research would need the combined scientific forces of many contients and nations and not just the usa and nasa. Which always hangs by a knife edge with washington usually doing their best to annoy the other national goverments.
Fire some asteroids or supply modules on a trajectory to meet up with the vessel during certain points on their trip--launch them in advance of the manned mission. I mean, if we're talking about a project undertaken by people who can expect to live several hundred years, spending sixty or seventy years launching supply modules or big rocks in preparation of a manned mission would not really be out of the question. If time is no object, neither are resources. I'm not sure why you're assuming that all of the resources would have to be carried on one ship. There's no reason that resource modules couldn't be launched ahead of time, like breadcrumbs for a manned mission to follow. They don't need all of the resources at one time, they need them in small amounts, delivered over time. You you just prepare ahead of time, with the understanding that unmanned supply modules can accelerate and decelerate faster than a manned module could.
The one's that are moving probably wouldn't be worth the effort of mining. They may have minerals but their extraction costs would be obscene. It would be easier to mine asteroids in the Belt and then shoot the comparatively smaller ore and minerals loads towards Earth instead of moving the entire asteroid which would probably be largely spall.
So you end up doing lots of Stop and Go. Therefore burning more R-mass and cutting your travel time even more.
Moon indeed has plenty of existentially usseful materials - hydrogen, oxygen, aluminium, titanium and lots of other useful elements. Moon also has a huge advantage in its proximity to Earth. Due to this reason alone, I think it is pretty much a given that first real off-world colony will be on the Moon. Pressure and temperature are not big hurdles for colonisation, so I dont think it is of much importance for choosing the right place unless the values are extreme. Maintaining a pressure vessel in vacuum is a routinely solved issue, why should that be a problem? What important volatiles are there on Venus? What structural materials are there in atmosphere of Venus?
Platinum. Dear god, the Platinum. So much of it by current estimates that platinum rims on a car would been seen as no different then cheap ass aluminum ones.
Well, you have to consider that it would take a very long time for the manned vessel to accelerate to its maximum speed, and then a very long time to decelerate as it approaches the destination. No stop and go is required because the supply module would be able to decelerate to match the manned module's velocity.
The actual utility of titanium without advanced production facilities is low. As for hydrogen and oxygen, extracting it from the rocks is far, far more difficult than electrolysis on water, or letting plants photosynthesize with existing CO2. Proximity is no good reason to go there. There's no point in putting a colony on the moon that has no hope in hell of being able to even marginally sustain itself. What's the point? They're huge hurdles! If a pressure vessel has to be built and maintained, suddenly space becomes extremely valuable and minor failures become hugely problematic. The actual cost of moving the colony's modules goes way up too--because they necessarily weigh a lot more than a gas-separation barrier made out of plastics that don't react to sulfuric acid. A colony established at 1 bar--even if the atmosphere outside is not breathable--could be far larger for the same weight. Temperature is also a significant problem, especially without an atmosphere to provide some regularity to the temperature. The solution to that involves fundamentally cramped spaces and extremely heavy pressure vessels that can easily fail. What's the point when all you'll ever have is a few thousand cubic feet of space? Building a colony in a vacuum fundamentally restricts the amount of space available and would radically increase the costs relative to something that requires only a gas-separation barrier to maintain a breathable atmosphere. Rather than thousands of cubic feet, something at 1 bar could have hundreds of thousands of cubic feet for about the same price. Nitrogen, sulfuric acid, CO2. From these, you can produce a human-breathable atmosphere, create water, create various polymers, grow plants, etc. Certainly, the lack of metals would be a problem, but one easier to solve than a lack of air and water. It's easier to ship durable finished goods (or even just raw metal) than to ship the essentials of life. It's easier to ship in dirt that can be fixed with fertilizers produced on-site than it is to ship food. Everything absolutely required to make plastics. Carbon, hydrogen, nitrogen, in vast quantities. Without the need for a pressure vessel, the need for huge quantities of metal would decrease substantially.
Docking with a spacecraft moving any decent percentage of the speed of light is an exercise in creating a non-nuclear megaton explosion. Even a tiny fraction of error would be enough to destroy both vessels. The spacecraft would have to slow.
A tiny fraction of an error when plotting the course would also cause the mission to fail. There's already very high tolerances on control and performance implied merely by launching the mission. I mean, if we've already solved the aging problem, docking two ships at relativistic speeds probably wouldn't be beyond the capabilities of such a society.
By "tiny fraction of an error", at those speeds, I mean nanometers off. You would have to marry the two craft up perfectly in order for something catastrophic not to occur.
There's a lot of perfect requirements in the entire endeavor. Getting two ships to line up perfectly would be the least of their worries. And frankly it wouldn't be beyond their capabilities given the other technologies implied by such a mission. "Extremely difficult" is not the same as "impossible". This is certainly less of a challenge than violating the laws of physics, because this approach is at least theoretically possible--it just requires an insane amount of accuracy. Getting there the slow way is at least theoretically possible. Getting there faster than light is, from all appearances, not. Getting there the slow way would be an amazing feat of engineering and coordination and scientific achievement... but it doesn't require rewriting the laws of physics. In this sense, it is the more practical approach to interstellar travel.
Still, advanced production facilities and ore processors on the Moon will be vastly cheaper and sooner than habitable plastic shell on Venus. Hydrogen and oxygen could be also extracted from lunar water at the poles. Hydrogen is also very light, it could be brought in from Earth with fairly low mass penalty. First, it has a very good hope of sustaining itself to a large degree. Second, I do not consider complete sustainability to be important. We will be glad to even have an off-world colony, sustainable colony is science-fiction and just a nice bonus. Please keep it real. In real world, proximity will be possibly the most important factor. I maintain my stance that pressure vessel is a solved issue. There is little maintenance needed, and what exactly do you mean by minor failures? Has it even happened before? As for space, why should large space be of great importance? Also, inflatable modules solve the issue. Single 65 ton Bigelow inflatable has a volume of 2100 cubic meters. Thats twice the ISS volume in one launch. It also has advanced 1 m thick wall with very good protection against any damage and radiation. Under a layer of soil, temperature on the Moon is fairly constant, and at cozy 23 C near the equator. Also, temperature regularity is of little concern on the ISS, where extremes of +-300 K are usual. So again, what is the problem? The point is to have a permanently manned off-world colony on another body. Is that not enough in itself? Anything more is science-fiction this century anyway. Whats the point of your colony on Venus?
Moon is more important. [ame="http://www.youtube.com/watch?v=uagbZmWcl7I&feature=related"]The Truth - Why Nasa Has Never Returned To The Moon Part 1 - YouTube[/ame]
Into the private sector and branch off any military applications to the military itself. America is broke and getting more broke with each passing minute PLUS more Americans are on food stamps then ever before. Yet tons of people want many of those same people on food stamps (those that do pay taxes) to fork over what little money they have so that a few dozen people can jump around on the Moon. You people want to have your - (admittedly cool) science projects - then fund them yourselves and allow those Americans that do not wish to spend their HARD earned tax dollars on them to not have to. Big government lovers spout off about how wonderful big governments are for society. But when push comes to shove - you are just bullies. Either people give you the money for whatever little projects you want or you throw them in jail for tax evasion. Pretty sad. BTW - if NASA went private and went looking for funds for their projects - I might throw them a few bucks (if I am interested enough). But there is a big difference between the government forcing you to fund EVERYTHING NASA does - and me being able to choose what parts of NASA I wish to donate to. But NO DOUBT many NASA lovers do not care about the difference and just want the masses to fund the projects they want - regardless of whether they wish to or not. It's the old 'trust the government - they know what is best for you' crap.
From my perspective, it is not that America is broke, but that many forms of entitlement spending do not promote and provide for the general welfare and common defense of the United States. Only public policy schemes which generate a positive multiplier effect may be rightfully termed, an investment in the general welfare.
