We see the propulsion breakthroughs right now - there's a wide range of propulsion systems possible with current technology. Unfortunately, the turnaround on these sort of things is measured in decades (generally with a number well over "1"). And if it has any form of the word "nuclear" in the title, multiply the average time from conception to deployment by a large number.

Nobody of course is requiring rockets to be our long-term future. I have a soft spot for the Loftstrom loop concept, for example (aka, a track that holds itself up via the centrifugal force of a rapidly spinning rotor magnetically suspended in a vacuum inside it). Way more efficient and high throughput than a space elevator and requiring no unobtanium.

It would of course not make fuel cheap until we can learn to mine cheaply in space. And we're not even 1% to that stage. You have to pretty much relearn how to do everything you take for granted on Earth in space. Look at Philae just attempting to softly touch down at very low speeds - it had four different ways to try to stop it from bouncing (shock absorbers, ice screws, harpoon, counter-force rocket), and it still bounced way off and ended up in some rocks somewhere. And you're picturing setting up a whole refinery there? Yes, some day. But that day is not close.

The radiation issue is a big one that a lot of people downplay (they forget that the only reason the Apollo astronauts got away with as little shielding as they did was that their missions were on the order of a week or so long - and even still, they would have been in bad shape if a solar storm had hit. As it was they reported seeing regular flashes of light from cosmic rays impacting their retinas.

There've been a number of proposals for how to deal with shielding. One is to build a mini-magnetosphere around the spacecraft; my last reading on the subject was that it would be a realistic way to deflect most solar radiation but not GCR. You still really need physical shielding (which is a complex topic... beta and gamma are blocked by heavy metals far better than they are by light materials, but neutrons need to be moderated down to be stopped effectively, which means light, high scattering cross section elements like hydrogen; heavy ions tend to multiply high energy neutrons. And to make matters worse, forms of radiation switch around - betas kick off gammas due to bremmstrahlung, gammas can kick off photoneutrons or betas, betas can kick off neutrons too, neutron capture kicks off gammas, transmuted elements decay releasing gamma, beta, positrons, alphas, sometimes neutrons... It's really tough.

Most proposals call for using fuel, water, oxygen, etc as part (but not all) of the shielding - it's particularly good against neutrons, as all of these things are generally composed of CHON, all of which are good moderators (especially the hydrogen). A common proposal is to have the heaviest shielding around the beds, as you get better bang for your kilogram that way. I've pondered a more advanced version of that, having significantly more fuel / water / etc tankage space than you need (the extra mass would be part of your shielding anyway, so it's not really a "penalty") and having a computer system intelligently pump it around to where people are at any given point in time and where the sun is / what the current solar radiation flux is / etc. I wouldn't be surprised if you could cut the radiation dose to less than half in that manner, possibly a lot less. You'd need durable, reliable pumps, of course.

If they actually told us how to program their microengines, something good might come of it. But they'll probably just BSD-license a list of numbers, as others have.

I liked writing bit-slice microcode at Pixar. I really could get every last bit of power out of the hardware.

Maybe you should learn what communism is before calling anyone "commiefriend". (Which I have to say, is really repulsive. It's sort of like picking your nose over the internet.) I think you are discussing the difference between lasiez-faire ecomomics and regulated markets. Communism is a very great difference in scale from that. And it's never been tried on a national scale just as "free market" has never been tried because there are always economic biases that make it impossible. What there has been so far is socialism.

I think you're missing the fundamental economic issue that drives all of this. It's the provision of essentially infinite amounts of credit. This is done by government, not banks. Essentially all home loans come from Fannie Mae or Freddie Mac, banks and finance companies are really just front-ends for them and sell their loans to the government once financed.

Given infinite credit, any scarce but necessary resource is going to be bid to absurd values.

It is by no means being a hippie to assert that government should not distort the market for credit, and to expect that urban and suburban land values would return to more realistic rates once the distortion was removed. Too bad that lots of people have already invested in unrealistic land values. They would have to lose.

Superconductors just exclude magnetic flux. I am not getting how it matters what produces the magnetic flux - be it ferromagnetic or electromagnetic. My only Meissner effect demo used a permanent magnet.

We have nVidia helping but not making their own Open Source driver. Intel, after a long period of Open Drivers, said it would require BLOBs for future graphical interfaces. AMD helps with Open Drivers more than nVidia so far but doesn't support them.

Maybe you need a Slashdot License. They come from the Ministry of Housinge.

There is no theoretical reason that a room-temperature superconductor cannot exist.

Room-temperature superconductors would be really cool. It's not clear that electromagnetic propulsion gets you to orbit, though. Once there, sure it works.

Multiple-Tesla fields that are changing their orientation rapidly in time aren't particularly healthy to be around. Induced currents in your nerves, heating, etc. That MRI field is acceptable because it's DC. That is, if you don't have any ferromagnetic objects on you.

No, the superconductors are not simple magnets.

What's on the tele then?

Rockets being the only solution does not automatically mean rockets are a viable solution. Please quit ignoring the real challenges presented.

Unfortunately, this can't be approached as an engineering problem and get the result you would like. It needs to be approached as a problem in fundamental research of the physics underlying our world.

There were lots of efforts to miniaturize the vacuum tube. They only resulted in smaller tubes. It took new insights in fundamental physics before people could understand how to make a transistor. There were many experiments with germanium (a natural semiconductor) that could have led to the transistor before 1947 if anyone had understood what was happening.

Some steel. Not all of them. That's why the refrigerator magnet doesn't stick to that silver door.

A field strong enough to work on water would kill you first.