Pinckney

Right, but how many people actually rent their own residence on Airbnb?

This seems to resemble more a problem of agency law. The recruiter was an agent of the government. Is the government liable for their agent's statements to potential soldiers?

>[Considering a swimming pool salesman...] Envision a situation in which a third party questioned the agent about the expected life of a chlorinator. Suppose the agent told the third party that the chlorinator's expected life was twenty years when it was actually only five years. Suppose further that the agent made this representation knowingly and with the intent to induce the thirty party to buy the equipment, and that the third party did buy this equipment in reasonable reliance on the agent's misrepresentation.

> Even assuming the manufacturer did not authorize the agent's misrepresentation, and in fact told him always to be truthful with potential customers, the manufacturer would be liable if the third party brought a common law fraud action against him. The court would determine liability under an authority analysis, applying the general rule that an innocent principle is liable for an agent's misrepresentations if the misrepresentations fall within the general class of statements that the principal apparently authorized the agent to make.

http://scholarship.law.wm.edu/cgi/viewcontent.cgi?article=21...

But why would a rational, self-interested person put up with great risk and expense to live in a small closed economy on Mars, when they could much more easily live in a small closed economy on earth? What's so great about Mars?

Nautilus-X was pretty serious.

You really want a pretty large diameter so that you don't have a huge gravity gradient causing your astronauts discomfort. Tethers might be more practical than the classical doughnut designs for the near future.

Surely Ceres would just fling itself apart?

Hi-seas isn't self-sustaining in food, water, or atmosphere.

Does this not get you banned?

Delta-v to EML1 from LEO is 3.77 km/sec. Assuming an Isp of 320 sec, you get a mass ratio of about 3.3, which works out to about 75 Falcon payloads, not counting any hardware you need to boost.

If you use ion thrusters, the delta-V becomes larger (7km/sec), but with an Isp of 3000 sec you can do it with only about 4.5 falcons. So this plan could be reasonable.

The real problem seems to be that crewed missions to the ISS probably can't use ion engines, and so take a huge payload hit getting there and back, right?

Also, won't radiation be an issue that far from earth?

It's like religion in that people like to anthropomorphize wildly. The Cosmological argument ("Define God to be the first cause") becomes "... and that's why God smote a fig tree."

Here, "Huh, the universe might have some funny symmetry" frequently seems to become "the Gods running the simulation we live in will turn you off if you ask the wrong questions", or some other similar wild leap.

It's not entirely clear what, exactly, it would mean for this to be true. It's also not clear that defining what we mean by "Is the universe a simulation?" has any value if it is not testable.

Galileo safely aerobraked into Jupiter at 47km/s. It takes one hell of a heat shield, but it can be done.

Another way to view it is that human rovers must go fast, because humans are impatient. We could build a faster, battery powered robotic rover if we wanted, but why?

If it's simply mileage you want, Curiosity's RTG means it can just keep going for years. With an average speed of 30 meters/hr, I'm not seeing much reason to think that it wasn't capable of covering ~1000km over those 4 years (the LRV, on the other hand, could never exceed 92km, total, before the batteries ran out). But mileage simply wasn't the goal.

Since Orion doesn't need to accelerate constantly, it's in principle quite possible to turn it and fire bombs in the direction of any interceptor, and the thick pusher plate makes it actually pretty durable from some aspects. What happens when two Orion ships duel, I don't know, but shooting it down isn't quite as simple as for most other spacecraft.

The big advantage of Orion is that we're reasonably confident it would work, and could probably build one within the decade with a serious effort. Zubrin's NSW rocket, on the other hand, falls into the "hasn't yet been conclusively proved impossible" category. We're not sure if we can control the reaction, and we're not sure how much heat would be transferred to the rocket if we can.

You add a significant amount of mass to the bombs to act as propellant. I don't know offhand what fraction is typical for Orion designs.

His cost estimates depend on hundreds of thousands of people signing up, to diffuse R&D costs. That's dubious.

Historically, colonists are self-interested. Typically they want to become rich, or they want to escape poverty or persecution. (Typically they're also poorly informed about just how dangerous their new life will be, and how much wealth they can expect to find, but in this age we shouldn't expect that to last much beyond the first landing). There's no precedent that I'm aware of for people leaving comfortable, privileged lives in mass to colonize someplace that has no wealth.

So? Nobody has been able to present any credible economic plan for Mars, either, which makes it more like Antarctica (or central Greenland, if you insist on somewhere you can legally move) than Norilsk.

I believe you're mistaken about the gravity. Position is as Re^(iv/rt), so |acceleration| is as Rv^2/r^2 -- right? For a fixed station of floor radius r, acceleration is directly proportional to distance from the center, R, so with r=1000m, a 2m astronaut will feel 99.8% of normal gravity at their head.

Assuming 5% variation from head to toe is tolerable, a 40m radius habitat would suffice, which could be rotated at 20m/s.

There has actually been research done on how humans tolerate rotational gravity (although not long term, AFAIK.) A 30% gradient at 0.5g is reportedly "disturbing". But perhaps long term one could become acclimated, just as one does at sea.

http://www.artificial-gravity.com/Dissertation/2_2.htm

The Brexit thread broke 2500.

https://news.ycombinator.com/item?id=11966167

Asteroids don't cause extinctions by coming in and blowing everything to smithereens. Rather, the ejecta causes firestorms, and an impact winter can wreck the biosphere and prevent sunlight from reaching the surface. But even during the worst of this, Earth will remain more hospitable than Mars.

There's no reason for a self-sufficient (nuclear?) underground or underwater habitat to notice global firestorms or impact winters. They would notice a direct hit, but you can hedge against that by building them in multiples around the globe.

If the government couldn't make other charges stick, they shouldn't be in jail.

A solar flare or a gamma ray burst might knock out satellites and electrical equipment and damage earth's atmosphere. In the worst case, they could kill a few billion people. But Earth will still be more hospitable than Mars.

>Same reason people crossed the Atlantic, to take part in something greater than themselves.

People crossed the Atlantic because they wanted gold, or slaves, or timber, or land, or because they wanted to escape from religious persecution, or because they were slaves or prisoners transported against their will (by someone who wanted gold, or timber, or land). They received resupply, not as charity, but from companies which expected to receive gold, tobacco, timber, or other goods in return from their investment.

Colonization is driven by economics. That's why thousands live permanently in Norilsk, Yellowknife, La Rinconada,and Kalgoorlie, but nobody lives permanently at Amundsen-Scott, under the sea, or in LEO. If history is any guide, "how will this turn a profit" is the question any Mars colony needs to address if it is to have any hope of prospering.

How many tourists visit Admundsen-Scott, and what percentage of its operating costs do you think it covers?

The technology to put people on Mars is not fundamentally new. The technology to make such a colony self sustaining is. We've never built any habitat which is entirely self sufficient even just in food, water, and air. Even the ISS needs resupply to generate breathable air. Even simple problems like "how do we replace failed bolts" will require resupply from earth for a long time.

I'm also dubious of the economics of this venture. I simply don't understand how living on Mars is advantageous for anybody. Mr. Musk is welcome to set his money on fire if he wants, of course, but I don't see a Mars colony ever being a rational investment for those of us on Earth, nor do I see paying hundreds of thousands of dollars to live a hard life and die in a frozen wasteland to be rational. I suspect after the initial enthusiasm dies down, very few people will choose this.

The problem with space elevators is that the cable (or the pipe, as you propose) needs to be able to hold itself together. Imagine taking a 4000 km long elevator cable and holding it up by one end: it would snap under its own weight instantly. That's about what your cable material needs to be able to take. The weight of the car is trivial in comparison.

What would they use it for?

If you're going to Mars, your vessel has a reasonable crew habitat, so you don't need Tiangong I for that.

Tiangong I is more payload than spaceship. Its tanks can only hold about 1000kg of propellant. Mr. Musk's proposed transfer stage has a propellant budget that's nearly 2,000,000kg.

Having to maintain compatibility with it may be hard (comms, docking, etc). There might be some hardware you could loot off it, but it's not worth flying a mission just for that, and launch windows mean visiting on a trip somewhere else would be prohibitively expensive.

I'll say it, sure.

Apollo was dangerous, expensive, and didn't accomplish anything that couldn't have been done more safely and cheaply with probes. It was cool as shit too, but I'm not going to pretend that 'cool' is a real basis for public policy.

Mr Musk is welcome to spend his money as he wants, of course.

Earth is still more hospitable in the case of your giant asteroid. Those in nuclear submarines and bunkers will survive unless they're very close to the epicenter. When they emerge, they'll find temperatures and atmosphere which are much more hospitable than on Mars. The survivors will also be able to scavenge abundant refined metals from the dead for rebuilding.

We can also start improving these facilities today, if we care about the survival of homo sapiens. Even out the gender ratio at Cheyenne mountain, give it a small nuclear reactor, a hydroponic farm, and a seed bank and we can be reasonably confident in it weathering anything but a very near miss.

From man git-stash:

"Applying the state can fail with conflicts; in this case, it is not removed from the stash list. You need to resolve the conflicts by hand and call git stash drop manually afterwards."

Or do I misunderstand you?

Suppose a state decides they're spending too much money on their court system. What would you say if they instituted a 5000% tax on criminal defense services?

What would you say if a state decided to impose a 5000% tax on abortion medicines?

What would you expect the courts to say about these taxes?

(Incidentally, this is not so different than the Mariana Islands' $1000 handgun tax. I thought this was currently being litigated, but I can't find anything confirming that.)