K^2

Which is ballistic drag. So even if it's a dominant effect, it's not going to cause tumbling. At the worst, it'd determine a different preferred orientation, which is entirely fine.

I'll second that. Personally, I like it better than OpenOffice, and you get the convenience of cloud storage, ease of sharing, and ability to import/export across a variety of formats.

Tidal pull would align first moment of density distribution radially over time, which means the station will be making one revolution per orbit rather than tumble randomly. In a high orbit, the station can stay there pretty much indefinitely. Or more specifically, until it has a chance encounter with an asteroid or other debris.

Was it capable of simulating 200+ objects at time warp factor of 1,000,000 with sufficient precision to give good predictions for all of the orbits well ahead? What you are talking about isn't even in the same category of problems. Try and write a simulation that manages to keep track of an asteroid or a comet in the Solar system. Then come back and talk about how easy it is to implement something like this.

Calculate proper velocity? Yes. Proper velocity is equal to coordinate velocity multiplied by Lorentz factor. Probably. Proper acceleration is the actual acceleration that the crew is going to experience, yes, so 1G proper acceleration would be quite comfortable. And yes, it also scales in a crazy way, so that it lets you have a round-trip to Andromeda Galaxy in under 60 years of ship time. Of course, it'd still be millions of years on Earth. Unfortunately, even with a photon drive, maintaining 1G proper acceleration for that long requires an unobtainable amount of fuel. (Edit: Note, proper acceleration scales differently from proper velocity. It is defined as rate of change of proper velocity with respect to map time. The actual factor depends on direction of acceleration with respect to velocity. But if you are accelerating/decelerating in direction you are traveling, then the proper acceleration is greater than coordinate acceleration by a factor of Lorentz factor cubed.)

What sort of a database? What are you planning to use it for? Does it need to have a GUI, or are you planning to query it via something like SQL? Or both?

That's just silly.

Because that's how gravitationally bound systems work. For motion of the Earth-Moon system around the Sun, for example, it's the total mass and total momentum of Earth-Moon system that's relevant. So as Earth and Moon interact, and Moon goes to a higher orbit, Earth's motion around the Sun is practically unaffected.

That would generate all sorts of weird torques that aren't good for the structure. The best solution would be for the centrifuge to carry its own counterweight. For a CAM type module, having two counter-rotating centrifuges would probably be the best solution. By canceling angular momentum within the module you save yourself all sorts of trouble. Yeah, I know, added weight, etc, but it's better than risking metal fatigue in some critical structural part holding the station together.

That's not result of a Saturn V launch. That's a result of a specific mission. Yes, Lunar missions ejected some junk from the system. This would make a contribution. But Saturn Vs were also used to launch Skylab. That resulted in no debris leaving Earth system. I've pointed out that there are some insignificant exceptions in the first post I've made in this thread. But claim that Saturn V launch causes any changes to Earth orbit is false. The launch itself does absolutely nothing. If you end up accelerating something past escape velocity, that's a different story.

That's also conjecture. Only ten people have spent any significant amount of time in something like .2G, and we are still talking days, not months or years that Nautilus-X is designed for. We have no idea what the threshold is for developing various health problems associated with microgravity actually is. I'm sure it's better than none, but is it enough to offset any problems that long term exposure of the same cardiovascular to the considerable Coriolis effect?

If it was size of the Moon, the Earth-SV system would interact with other planets a little differently, which could result in a difference. But from a rocket launch, you take a tiny perturbation to Earth's position times tiny perturbation from interaction with the planets, yielding a perturbation so tiny that it does absolutely zip. What these people did was actually take the momentum of the rocket out of Earth's. And that's not how it works, because Saturn V does not escape Earth's gravity. So total Earth system momentum remains the same. It might get distributed slightly differently between Earth, Moon, and all satellites natural or artificial, but the total is exactly the same, resulting in exactly the same motion of Earth system around the Sun.

No, it wouldn't. Earth system's barycenter would continue on exactly the same orbit.

The reason I appreciate Skyler's idea is not because it controls population so much as it creates a bit of selection based on IQ. Not so strong as to cause major problems, but enough to nudge it in the right direction. Currently, people with higher levels of education, income, and intelligence, tend to have less than two children on average. When the overall population is growing or stable, it's kind of a scary thought. Fortunately, we're on the edge of starting to do genetic modifications of the future generations, and the "improved" genes are bound to trickle down through population, so I don't think we're in serious danger of degradation, but it'd be nice to provide other incentives for improvements as well. Just so long as we don't do anything drastic or get down to full-blown eugenics.

I would like to see that centrifuge demonstrated first. I have serious doubts about its utility. An accepted range is 2-7 RPM, with rotation bellow 2 RPM believed to be suitable for pretty much everyone, and that above 7 being bad for almost everyone. Since we don't know how long it will take for problems to develop, a long term mission would probably be limited to 4-5 RPM. So that's 10-20% of Earth's gravity that we can count on. I suppose, it's better than none, albeit, at a price of some discomfort. But is that going to be enough to make a difference in a long term mission? It just seems like long term risks outweigh benefits here. Of course, a lot of this is conjecture, and the rest is based chiefly on Earth-bound studies. So it might be possible to select a crew that will adjust to a higher RPM and get it to a high enough fraction of Earth's gravity to have significant utility. But we really won't know until we try it out on ISS. So I'd definitely push for the demonstration centrifuge on ISS, and wait to see how it goes before pushing for Nautilus-X as a whole. Also, what a silly acronym. If they do end up developing it, they should have a competition for a better one.

You've just taken the segment of population that can't afford to have any children, but breed anyway, raising children on welfare, and made them even poorer. Edit: Don't get me wrong. I'm not saying the idea itself is bad. It's just that I can't think of any way to make it work without ending up with all sorts of other problems, and probably an armed rebellion in the Southern States.

And you are planning to enforce that how?

That's not a problem. You can build up to GTO from LEO on VASMIRs. Might have to refuel here and there, but nobody said it has to be on the single "tank" of propellant. I looked at the info on SMART-1. That's actually a surprisingly smooth transition. I didn't realize there were such simple transfer options. So yeah, looking at that, I'd say it's definitely possible to move ISS to Moon orbit. Might cost a hell of a lot and take a long time, but it can be done. I'll have to think about this. Maybe I'm thinking about it all wrong, and 3-body actually makes things easier due to L1. Hm...

On a fly-by or actually getting a capture? If you have a link, I'd be interested in taking a look at what sort of maneuvering it'd take.

You can raise ISS's orbit until it matches Lunar. So you can stick it in on of the Earth-Moon Lagrange points. The problem is going to be getting captured by the Moon. ISS cannot withstand any significant acceleration, and getting a capture with minimal thrust in a real 3-body scenario seems like a huge challenge.

For the coasting part, you'd definitely have to go with rotation. Any other form of artificial gravity makes warp drives look like toys. For acceleration and deceleration, it'd be nice to maintain 1G simply through that, but it might be tricky to do with NPP, which is our best bet right now. One thing for which a Bussard Ramjet might be ideal is deceleration. You can definitely design one with reverse thrust, in which case drag is actually helping you slow down. That way you can do a 1G deceleration "for free" all the way to the target system. Depending on the design, this might also work as a re-fueling stage, in case you have to send the ship on to the next system. It's hard to come up with any single-stage system capable of significant fraction of speed of light, though. But even if it just works as a brake, you can effectively double your cruise speed for the same size ship, since all of your delta-V would go into speeding up. So if I had to do a proposal fro an interstellar mission based on current tech, I'd go with Orion-type drive for speeding up, and Bussard Ramjet for slowing back down. This is still only conceivable, with technology and world resources as they are, as an un-manned mission. Manned mission would have to be a generation ship, as you've said, making it much, much larger, and requiring a whole lot of other provisions. Gravity, as you've mentioned, but also shielding, life support for an entire colony, way to renew or regenerate resources from water, to air, to food, and ways to patch up or even rebuild anything that goes broke during the decades or centuries that the ship would be in voyage. Even if we sort out technology, all of Earth's governments and corporations combined don't have resources to make a dent in a project like this.

If you assume something that's false, you can arrive at any conclusion you like. Real planets interact. Their orbits are stable even with respect to each-other. I was just being lazy. Since we are talking about planets, by "year", I mean one full revolution around the parent star. So yeah, the former. But if we are talking about Earth, there shouldn't be a difference, since changing period requires significant change in semi-major axis, which you won't get with any minor boost. So it should be the same thing to any significant precision.

Right now, warp drive seems a more plausible way to approach the speed of light, and potentially FTL speeds, than any kind of reaction drive we can imagine taking us to 90% of speed of light. 10% we can do without tapping into Gen-Rel for sure, but significantly beyond that, we really have to go with warp. Even with matter-antimatter photon drive, .9c is likely beyond reach, not to mention practical use, and a good photon drive at these sort of efficiencies is already beyond physics as we know it. So if we can't do warp, I don't think we are ever going to do human interstellar flight. No telling what trans-humanity will bring, of course. We might simply get to the point where distinction between manned and an unmanned mission is non-existent and then take the slow and steady approach to space colonization. But I haven't lost hope in warp drives yet.

It's very difficult to re-direct flow without any drag. But here, you aren't just trying to re-direct it. You are trying to heat it up to use it for fusion. That energy has to come from, and the only place it can come from is from work of the ship on the gas. That means there is going to be a corresponding work done against the ship. Ergo, drag. If you have an alternative energy source, you can have a low-drag scoop, and use linear accelerators to push off of the flow. It's not very efficient, but at "low" speeds, such as 10% of speed of light, it can still be more efficient than a photon drive, so it might be worth it in interstellar missions. Problem is getting all that energy. Unfortunately, even a nuclear reactor is going to be too much mass to drag if you want to actually get to 10% of c. Hence the idea of using hydrogen as fuel, and hence the drag.

1) Interstellar gas generally moves at a pretty brisk pace, and there are currents. I wouldn't worry about it. 2) There are ways to shield interior of the ship from magnetic fields. As for the structure, just don't use ferromagnetic materials. 3) The original ram jet idea worked off nuclear fusion of the incoming hydrogen. The idea is that at a sufficiently high speed, the gathered hydrogen would heat up as it compresses and reaches sufficient temperature for fusion. The rest works like a conventional ram jet. (Well, a scram jet, actually.) The problem is that this turned out to generate too much drag and not enough thrust. So it would need additional power to keep it running. There have been a number of suggestions on that, but I'm not sufficiently familiar with them to say which are feasible.