I do not want to get into a long drawn out debate about shielding…..yet again.

NASA may be “stumped” but the guaranteed solution was explained to the general public several years ago by a recognized authority on space radiation. Eugene Parker specifies 15 feet and 500 tons of water to completely shield a small capsule.

I call this the Parker/Dyson/Spudis effect.

Parker explained the problem and detailed the solution, Freeman Dyson long before this provided the means to move the required shield around the solar system (nuclear pulse propulsion) and the work of Paul Spudis revealed the site to acquire the shielding and light off nuclear devices: the lunar poles.

That NASA does not seem to have anyone that can put two and two together and effect a solution is not my problem.

Well, you are talking about it……I am talking about radiation. I was NOT assuming anything except the fact that the only way to stop the heavy nuclei component of galactic cosmic radiation is mass and distance- “active shielding” does not work. I am not a sea monkey or a tardigrade and “impractically thick” may be the NASA position but it is not reality.

An often overlooked fact is that passive (material) shielding is not a radiation all-comers solve it all. Actually, it aggravates the HZE GCR problem, i.e., less the shielding is really and impractically thick, even for ‘water tiles’. NASA knows this quite well and remains stumped, as can be gleamed from their Mars GCR open-source challenge.

You’d have to be a sea-monkey (brine shrimp) or maybe a tardigrade to cope with a direct radiation hit and survive; these critters rely on extreme dehydrationq (anhydrobiosis) for coping with low-level radiolysis and, at least in the case of the shrimps, they have DNA repair molecules and proteins that lack a fixed structure. Even despite surviving heavy GCR hits, the Apollo 16/17 Biostack I/II experiments showed deformities in the survivors. By the way, these critters can also tolerate cryo temperatures. The only thing that was found essentially insensitive to HZE radiation was bacteria (and plant spores ?)

I’m all for radical perspective shifting or zero to one thinking but I’m also a pragmatist. We’re now starting to talk about sci-fi transhumanism beyond the realms of reasoning or even blue-skies innovation, i.e., it would require multiple major biotechnological miracles to pull off. Quite simply, we’re talking about a challenge with a very near zero doability factor.

I get so upset sometimes a can’t even spellcheck; When it is realized a Saturn V launch did not turn out to be much more expensive than a Space Shuttle launch then……….

My point being if we had just kept launching Saturn V’s (and more efficient iterations of that vehicle) and kept exploring the Moon- even with robots initially- then we would would be up to a couple hundred missions by now. The ice and lava tubes would have been mapped, human missions resumed, and a permanent lunar base now in operation for the same money.

Instead of the do-everything-pay-for-itself-cargo-bay-of-dreams and the deteriorating space station to nowhere.

This kind of “what if” hindsight is extremely important. If we do not learn from our mistakes we are doomed to repeat them. The hobby rocket is essentially just a cheaper nastier version of the same concept that has kept the U.S. trapped in LEO for almost half a century. There is no cheap.

A cryogenic temperature means no calories are consumed and the “holding pattern”, if not for radiation damage, would be indefinite. There are no numbers on this yet, but even a completely shielded frozen human body would still suffer damage from decaying isotopes already in the body and would have to be revived periodically to allow for a month-long natural DNA repair period. How grievous the accumulated damage would be if left unchecked is unknown. What the optimum repair frequency would be, whether 50 years or a thousand years, is unknown.

Twenty thousand or so H-bombs could kick such a ball to a small percentage of the speed of light and send it on its way to another solar system. No real technical obstacles to doing this (as Freeman Dyson pointed out nearly half a century ago).

Of course condemning many generations of human beings to living inside such a sphere their whole lives does not seem very practical. So I would say there is only one technology missing; freezing people. Unlike warp drive and transporters it is not such a difficult advance to imagine. The main problem being preventing ice crystal from forming at a microscopic level and disrupting cellular walls. A form of this is already being done in the food storage industry.

http://www.forbes.com/forbes/2008/0602/076.html

And of course, actually being able to freeze people is the ultimate disruptive technology that would change the human condition far beyond simple star travel. Freezing our loved ones and ourselves until a cure is found for whatever is killing us (most often old age) would become a basic human right and drag civilization kicking and screaming into the larger universe.