NERVAfan

If the different interpretations of QM are indistinguishable within QM, is it possible that a future 'theory of everything' might make them not indistinguishable in the broader context? Or is which one is "right" forever purely a philosophical question?

Probably not until NASA works with China (IIRC it is actually forbidden to do so by Congress). IMO that should totally be changed... we could do Apollo-Soyuz during the frickin' Cold War, but we can't cooperate with China (who actually has an operational manned program, unlike the US currently) in space?

It does seem kind of a long time span... I don't think comparing it to Apollo really works, this is a (probably fairly small) unmanned spacecraft with modern computer technology, and it might even get a rideshare on a NASA mission or something.

There's no evidence that you can accurately extrapolate risk to that extreme of low dose/high population. Yes, the linear-no-threshold model of radiation risk produces that number, but that doesn't mean it reflects reality; that's extrapolating so tremendously far beyond the data the model was based on. It's pretty likely (IMO - this is hotly debated) that there would be no deaths. The showstopper problems with Orions are politics (anti-nuclear fear and nuclear proliferation concerns), EMP, and likely cost, not radiation.

How will we decide which solar setup we go with? Are we going to vote? I think we need to decide soon since the power available will determine lots of other things. Also, are we going to lose enough heat through the radiator panel to keep the moss alive in sunlight?

There have been several cubesats Kickstarted and successfully launched (SkyCube, ArduSat, KickSat... though KickSat failed to deploy its contents due to a radiation issue). And Planetary Resources raised $1.5 million in a Kickstarter for one of their Arkyd mini-space telescopes; that hasn't launched yet, but they're working on it (a testbed spacecraft actually got blown up in the recent Antares launch failure... but they're continuing with another.)

Yeah, I don't think $150,000 is at all typical for building a cubesat. Yes. Thermal control will be absolutely critical. Do you think this radiator will be enough to keep temperatures within a tolerable range in sunlight? We might need a heater as well...

I am talking about a reused vehicle, not a classic expendable rocket. Each vehicle would fly hundreds of times and the number of vehicles would be small. So you could test fire each vehicle's engine a couple of hundred times too.

Yeah, nuclear pulse makes interstellar workable for humans. And I do really think that it does matter that humans do things (OTOH, I do not at all believe in human-like AI - even if they were created that way, they would very rapidly become wildly nonhuman). EDIT: And given interstellar dust/hydrogen, I don't think there's much point in sending unmanned probes - I'm pretty skeptical of the super-light laser-powered-sail probes people talk about surviving at even 1% of c. An interstellar craft should be armored so heavily -- and therefore so huge -- it might as well be a worldship/generation ship.

It would be quite silly to build a giant orbital battlestation and not armor it to stand up against orbital-speed impacts. If you had access to an Orion drive to launch (basically making mass into orbit irrelevant) -- which is about the kind of thing you'd use for this -- you could probably armor it to not take any significant damage (IE a hole in the armor, but not affecting any systems). If you were going to build such a thing at all, it would be able to avoid big debris and ignore small debris.

I don't think a cubesat would be nearly enough. Say 1 kg mass, relative velocity 10 km/s; that's "only" 50 Megajoules or the equivalent of about 12 kilograms of TNT. I'm pretty sure a well-designed armored giant orbital battlestation could stand up to that pretty trivially, especially if you designed the armor for space impacts (multiple layers with vacuum in between, like a Whipple shield) rather than like an ocean warship. If it was sufficiently compartmentalized, it might actually be pretty hard to destroy, especially since it can't "sink".

I'm not sure I agree. Let's say you have simple, pressure-fed engines, and a one engine rocket, and it's reusable, so you test fire it 10,000 times. And it depends on the risk you are willing to accept, anyway. Not all organizations will be as risk averse as NASA currently is.

I imagine there is a price point at which they would be interested in buying flights (same for Brazil, South Korea, Israel, etc.) Depends how cheap flights on the reusable vehicle were.

Well... a gas envelope, extremely theoretically, maybe - the square cube law works in the favor of buoyant things like airships.... the bigger it is the heavier the envelope can become. But the needed size would be so huge that it would never be financially feasible. Something on a scale of miles might be able to afford quite significant armor though. http://en.wikipedia.org/wiki/Cloud_Nine_%28tensegrity_sphere%29 (and that would have been lifted just by a slight temperature difference - if it was hydrogen filled, the lift would be vastly more.)

That's an incredibly high standard for acceptable safety - assuming roughly 1% chance of fatal accident per Space Shuttle launch, four or five orders of magnitude better would be about 1 in 1 to 10 million launches. The Space Shuttle's level of safety was IMO unacceptable because it was seen as 'routine'. For a nation just starting manned spaceflight, or for doing something genuinely new like going to Moon/Mars, 1 in 100 chance of death is not that unreasonable (Antarctic exploration in the early 20th century was quite a bit worse than that EDIT: Anyway, you wouldn't have to sacrifice all launch-escape capability. You could still escape from a first-stage failure like the recent Antares one, and some 2nd stage failures would allow a return, too.

I was thinking in terms of selling flights to governments with significant space agencies but without an in-country manned spaceflight capability - India, Japan, etc. I don't think there is currently anyone for them to buy manned flights from.

3 "front" faces covered. 3 panels at 58% exposure. 3.5W production. Rotation axis connects opposite corners. Advantages: Best usage with fixed geometry. Drawback: Trying to pack everything around a diagonal.Would the diagonal make the gravity variation across the moss itself worse/messier? If not, or if that's workable, I think this sounds good.

Any government, or just US/NASA?

Or the shuttle used something like a gas-core nuclear rocket or nuclear-salt-water-rocket that wouldn't be allowed to launch from Earth...

No one else available had any flight experience at all. Cooper objects that he's never been out of the stratosphere, and the old professor guy says 'the others have never been out of the simulator'.

Right. If the Sun became a black hole, the Earth's orbit wouldn't change (within Kepler's laws level of approximation anyway - ignoring possible small effects from the Sun currently not being a perfect sphere etc.) Generally the crazy stuff doesn't start happening until you get much closer to the black hole than the surface of a comparable-mass object of normal-matter densities. (You can't orbit the Earth's center closer than about 6500 km because the Earth/atmosphere is in the way, and once you get under the Earth's surface some of the mass is above you, so the gravity stops increasing... if the Earth were uniform, it would linearly decrease, but the core being denser makes things more complex.)

If the rocket engines can be made/proved to be reliable enough, maybe it wouldn't have a launch escape system. Depends who is building it and what risk they are willing to accept.

Yeah, the Green Revolution in agriculture seems to have taken pretty much everybody by surprise. And I don't think many people realize how high the theoretical limits are. Cellulose is made of sugar - it has tons of energy - we just can't digest it. If we commercialized a way to break down cellulose into sugars - and people are working on this for biofuel purposes - then all the corn/wheat/rice stalks become a potential calorie source, massively multiplying the calorie output of most of the world's farming regions. More speculatively... photosynthesis only converts a couple percent of incoming solar energy to chemical energy. This might be significantly improvable by advanced-enough genetic engineering. And then there's the possibility of de-desertifying the Earth's deserts (the Sahara was apparently mostly grassland up to ~7000 years ago...)

Feeding 45 billion people wouldn't require imports for a civilization with interstellar-level tech. We could probably get Earth's food production level up to that in less than 50 years (maybe quite a bit less) if we wanted, assuming we didn't care about preserving natural environments and were willing to stop being irrationally afraid of GMO crops.

There are already algae* that produce all essential amino acids! Spirulina does it right now, no modification needed, and is quite edible - it's eaten as a dietary supplement (though some of the health claims for it are made up). *ok, cyanobacteria technically, but some people consider them algae anyway... I wouldn't start messing with human DNA - much more ways that things can go wrong, and much worse consequences if they do. Something like Spirulina is vastly simpler than a human - by orders of magnitude - and mistakes don't end up hurting/killing human beings.