K^2

Does it have to fly unmanned? It looks like it can sit one. I'd give it a shot, if they needs volunteers.

Then it's spinning at 2.82m/s. If some speed is 2m/s bellow orbital and 4m/s bellow escape, escape velocity is 2m/s higher than orbital. But escape velocity is always square root of 2 times higher than orbital. This is entirely possible for a tiny moon.

I think, you'd have to design these things very differently. A long slender body with two pairs of glider-like wings - front and back. That will give you a significant moment about the roll and pitch axes letting you gain some of that maneuverability back. But yeah, you'd still need to land that thing somehow? Maybe same way you'd take off, with JATO?

Same problem. No oxidizer in the air. In addition, the dust in atmo would FOD out any turbines pretty quick. But props would work. They just need to be very large and very rapidly rotating. A bit of an engineering challenge, but nothing impossible. To drive them, you'd either use electric motors or turbines driven by rocket engines. (Since these do not intake air, FOD wouldn't be an issue.) I was actually considering building a prop mod that would let you design a craft for different kinds of atmosphere by combining different turbines with different props. I might still do that. Would make exploration of Duna way more fun.

The ship in the bubble is in flat space-time. But the energy that generates warp bubble is not. The bubble would interact with other masses. It will most certainly not go in "direct geodesic," because there is no such thing. "Direct line" is a very relative concept in GR. It is all a matter of metric. The other argument is from conservation of energy. If your ship gets off the orbit, where does the energy for it come from? Energy in the bubble does not change in the process. Rubbish.

You know... I have no idea how a warp drive would affect orbital flight. It might be that you'd follow the same trajectory you would without it, only faster. And I don't even know how to do the math required to check that. I can do very basic math with the warp metric and I can do very simple math with the Schwartzschild metric, which would describe gravity around the star. But combining the two? That requires solving Einstein Equation for the combination, and while there is probably a good way to do this approximately, I wouldn't know where to start.

Bah. There should be a warning. "You're about to post in a thread that has been recently necro'ed. Are you sure you want to continue?"

Like I said, there wasn't a lot of discomfort at 3G. I mean, if I had to move about significantly, that'd probably be tough. But as far as just maintaining control of the aircraft and breathing, it wasn't bad at all. And no, I don't have a license. I don't have enough hours at the moment, and just now I can't afford to get more flight hours. So getting the license will have to wait. I've completed the ground part of the flight classes at my university, however, back when I was able to take classes for free. All of my paperwork is out of date, of course, so I'll have to take the exam again, but I shouldn't need to sit through ground school again.

You can get permission for a high power amateur rocketry launch, at least in the States. There is some paperwork involved, mostly in making sure the FAA can issue NOTAMs for the area, but it's very easy compared to the challenge of actually making the launch. So basically, if you can build an actual rocket, getting permission to launch it is the easy part. As far as actually getting something into space, depends on what your definition of getting to space is. In 2004, CSXT managed to put an "amateur" launched rocket into space, reaching altitude of 116km. This is far from establishing orbit, however. No "amateur" launch has gotten even close. And here, "amateur" just means something that wasn't built for profit. It by no means represents the expertise of people involved. So if you want to put something in orbit, you'll have to purchase room on one of the commercial satellite launches. As it has been pointed out, cubesat launches tend to be relatively affordable.

Warp drive isn't really a propulsion device in the traditional sense. You can use it to get somewhere faster, even without going FTL, but you can't use it as your only drive.

Airplane. An old fighter trainer. They only let me do a few simple maneuvers, "high" G turn being one of them. Instructor showed me a few others, though. Do any roller coasters actually pull 3G? I mean for any significant duration. The fastest linear accelerator one I've been on was the Top Thrill Dragster in Ohio, and that thing only pulls something like 1.3G average over 4 seconds, so maybe peaks at 2G? I suppose, one can do a bit more on the loops, but again, nothing I ever rode felt close to 3G. Edit: After looking around, it seems that some coasters do pull up to about 4G. I need to find me one of these.

Apollo did direct re-entry, which means the ship plummets into the atmosphere at the speed it gained "falling" from the Moon. All that speed has to be bled off in atmosphere, which there isn't a whole lot of. Hence the high G loads. 7G is not the limit of human tolerance, though. 8G+ is not unheard of for fighter pilots. Aircraft carrier take-off is going to be in the 6-8G range. Higher G loads can be pulled for certain maneuvers. Another factor is duration. Tens of G are entirely survivable if the duration is very short. It takes quite a bit before you start having actual tissue failure. Typically, the first thing that happens is the pilot blacking out due to blood pooling at the extremities. If this condition is maintained for too long, brain damage can occur, followed by death. At higher G loads, you can have blood vessels rupture in even shorter time, which can also lead to severe injuries or fatalities. All depends on how long the acceleration is maintained, what orientation the pilot is in, and whether you have any special seats and/or suits to assist him. The highest load I've been under is 3G. It's not that uncomfortable, and would be entirely acceptable for space tourism. You might be able to get away with 4 or 5 for a short duration. But anything higher than that, you need special training, special suit, etc., and that doesn't really work for commercial space flight. As far as ways to reduce the G loads on re-entry, all you have to do is slow down with engines before you drop into atmo. That can be expensive, but presumably, if you are doing commercial space flights, you have the overhead to do that.

I'm not very good with making the mechanical parts for these things, but I can do the electronics. I can build all the necessary circuitry to read off positions of all the switches, levers, and joysticks, and to communicate them to a PC via USB connection. So if anybody wants to team up and make a few of these, I'm up for it. Or if anyone has experience with setting up production of these in China, or wherever, we can probably do a Kick Starter. I've been actually wanting to get into this for a while, but like I said, I only have experience with the electronic/software part.

Outside of the warp bubble, the space-time is flat. So there is no gravity generated by warp drive out there. There is also the interior region which is flat. The space ship is located in the interior and also does not experience any gravity. And then there is the boundary region in between. That's what actually makes the warp bubble a warp bubble, and space-time there is very much distorted. That does result in quite a bit of gravity acting on anything that passes through the warp bubble boundary. The boundary could extend quite a bit around the ship, in which case, you can run risk of damaging something or throwing it out of the orbit, but to shift something as big as a planet, or even a small moon, you need an enormous amount of energy. If we need that much to make the warp drive work, we might never get that far with it. At any rate, any safe operation of the warp drive would be such where there are no objects within the bubble boundary. In which case, you do not run any risk of affecting orbits of planets or the like.

First of all, having metal screws in your rocket, especially around the engine - really dumb. These things do, occasionally, explode. And then these screws would have become shrapnel. Think about that for a moment. Second major safety hazard is lack of parachute. Did you see how far the rocket buried itself in the ground? Now picture that with someone's car. Or worse, head. Not terribly likely, but these things happen. That's why certain safety rules exist. I strongly recommend you read the Safety Code of the NAR and try to stick to it.

For starters, the planet would fall apart.

Not only that, but there are already plants with more than 2 copies of each chromosome. So in principle, these would have no trouble supporting more than 2 partners on the genetic level. Gamete production is also not that difficult. I am slightly concerned with gametes finding each other, though. If you need one of many sperm to find one of many eggs, that's one thing. If you need several different sperm to find the same egg? That's a whole different story. But yeah, what it comes down to is that it's something that's very unlikely to evolve to begin with, and then doesn't really provide that much advantage over having just two partners. It's easy to imagine that a particular cell might end up having a genetic defect resulting in a mitosis before DNA replication step. That would produce two cells with half of the DNA. If each one can go dormant, then it's just a matter of two such cells bumping into each other and fusing again. The rest is just optimizing the process. Anything that would allow for more than 2 partners is a much more complex mutation.

This is a good starting point. In a nutshell, sexual reproduction is derived from sexual reproduction of a single celled eukaryote that is the common ancestor to all multicellular organisms. While it's not clear how or why that particular species gained that particular advantage, it is what allowed significantly faster evolution of its progeny, ultimately allowing for complex multicellular life.

And how do you picture collision with a wall at 1.5c when you can't be moving relative to wall faster than c? But it's nothing like .96c into the wall, either. In fact, it's the same result as in classical mechanics. You get twice the energy of one ship hitting a wall at .75c. Same damage to both ships. What I mean is that both ships will evaporate, but if you measure the hard radiation released...

From perspective of the two ships, the message was delivered across a span of 3.3 light years at the speed of 0.96c in 3.4 years. It has absolutely no correspondence to what the 3rd observer has witnessed.

Third reference point always results in weird stuff in SR. You can have events appear to happen in the wrong order, things instantly jumping from one location to another, duplicates of objects... It's a mess. A fun mess, but a mess.

Fair enough. But that's the source of confusion, at any rate. People were talking about relative speed in the beginning. Anyhow, closing speed is not really "physically relevant". E.g., you cannot use closing speed to send information from point A to point B at 2c. That's really the proper test of speed limit violation. Of course, speed of light is a local limit. Hence the warp drive, etc. But we had a lengthy discussion of that in another thread. I think it's safe to assume that in this thread we're talking about local violations.

You are confusing closing speed and relative speed.

So we're only a couple of decades away from sustainable fusion energy. Business as usual.

Neither of these are valid. You can't say, "You are traveling at high fraction of c". You can only say, "You are traveling at high fraction of c relative to ..." And the rest of the universe travels at very different speeds. Now, what you can say is that you are traveling at high fraction of c relative to nearby stars. The stars within a few hundred light years, id est, all the visible ones, are not going to be moving very fast relative to each other, in general. So you can take their average velocity and measure speed relative to that. (Or the interstellar medium, which should be moving about as fast.) In that case you can say that if you are traveling at high fraction of c relative to these, they move at high fraction of c relative to you. And since these are going to be the only objects you see beside your ship, we can now talk about what sort of an effect this has on what you are going to see. So that's the answer to the OP's question. It's not the fact that you're moving at high fraction of c that changes how things look. It's the fact these particular objects you look at are rushing by you at high fraction of c that makes them look that way. And that's an absolute regardless of your chosen frame of reference. So there is no contradiction with speed of light being a constant.