shynung

Liquid Nitrogen ocean, yes. Under the surface, not necessarily. What if, in such a planet where there are landmasses and ocean, the 'land' are just frozen water?

Life that needs liquid Nitrogen instead of water to live? If there are any, they'd survive in very cold, far away planets like Eeloo. EDIT: I think this is a good start for a rough guide.

That is intended. This was a lifter design; it was to lift heavier stuff to orbit. This early design is rather fragile; the finished one has more strutwork on it.

Sorry, I meant shallower.

Much appreciated

Thanks, this is what I'm looking for. BTW, here's the craft in works: The Mk1-2 pod and upper stage is just a test weight of some sort. I was designing the lifter underneath. It was to be a general purpose lifter in subassemblies, so I don't have to make an entire rocket just to launch some newly-designed pods/sats/probes/whatever. I'm planning for a 6-booster craft after this (either 7 Mainsails, or 6 Mainsails and a Skipper).

OK, here's my problem. I have designed a 3-man capsule with only enough fuel for orbital maneuvers (typical space capsule), launched by an orange-tank-Mainsail core booster, augmented by 4 identical boosters in a 3-stage asparagus staging arrangement. If I were to launch using the straight-up-and-45-degree-after-10km ascent profile, I end up having to do a 900m/s2 circularization burn. While carrying the core stage to apoapsis and using it for the circularization burn is possible, it makes the whole spacecraft hard to turn, and end up orbiting as space junk once the burn is over. I need a shallower ascent profile that maximizes effective ÃŽâ€v while still in atmosphere to minimize ÃŽâ€v needed at circularization burn, so I could drop the core stage mid-flight. Can anyone explain?

Actually, no. Distance and speed still means the same thing, whether on the ground or in space. The recent Curiosity rover sent to Mars was powered by RTGs. In this case, the public at large, including politicians, know little about it. Photon sails don't necessarily need laser facilities, they still work on Solar radiation. And when space travel is as common as air travel, laser facilities could be as common as airports, but only if laser beam propulsions have advanced that much. The reason might be because they find space exploration lucrative. For this, things such as asteroid mining and moon mining must be feasible and relatively safe. Other than that, space manufacturing and storage facilities might also be highly profitable. A kilogram of water, while almost worthless in many parts of the world, carry premium prices in orbit because of the expense to lift them off from the surface. Same goes for various metals and elements found in moons and asteroids.

Further, maybe, but not faster. Ion engines, while possessing high specific impulse, have little in the thrust department. Chemical rockets need enormous fuel tanks for an interstellar mission, even for small probes; Voyager 1 & 2 took multiple gravity assists in order to get where they are now. My bet for an interstellar mission would be when the first NTR took flight. It had been studied extensively in the NERVA program, and deemed ready for integration into current spacecraft designs. If the political climate and public fears on anything nuclear were nonexistent, an NTR spacecraft could be launched in the short term. If not NTR, photon sails could also do the job. It works by capturing light pressure, either from the Sun or a laser facility, and use it to propel the spacecraft. It needs neither propellant nor electricity from the spacecraft itself, and it works indefinitely, until the laser is turned off or the Sun died. The caveat is that it produces very small amounts of thrust; on the orders of micronewtons to millinewtons. It would take decades to make significant maneuvers.

For this idea, an automobile turbocharger's turbine could do the job.

The UN's existence clings to the fact that powerful countries make up the bulk of its capacity. Considering the social problems typical in modern society, even if the UN were to succeed, there would still be sociopolitical problems. But I digress. Right now, we still have to research things like fusion and antimatter power. Considering it's still in its infancy, it would still take quite a while before the first fusion drives are flown. Most likely, we would not be around to witness it. Yes, I did mean near-light-speed. It might sound like a quantum leap, but we'll get there eventually. Let's hope some disgruntled army general didn't start an apocalyptic war in the middle of the progress, and reduce everyone back to the dark ages.

We must. There isn't enough resources on any planet that could run any civilization indefinitely, even with extensive recycling and conservative energy mining. Even the sun will die out some billions of years into the future, rendering the Solar system barren. On fusion tech, if we were to research power generation reactors, we may be able to get more leeway. If so, things like VASIMR or other kinds of high-energy electric propulsion would be the order of the day. Plus, with enough relativistic speeds, time dilation effects will kick in. Even normal humans can live for thousands of years if living in a spacecraft travelling fast enough. This kind of speeds is the problem where Orion, fusion drive, or any other drives try to tackle.

Project Daedalus was dealing with a complete spacecraft. I think the specific technology (which Daedalus planned to use as well) is inertial confinement fusion drive. We have to develop fusion first, obviously, but I'm confident we will have it before 2100.

I propose upgrading the Orion drive to fusion fuels.

High-school biology is pretty basic, at least in my country. It gives students background knowledge for those going to study related sciences, such as genetics, biochemistry, pathology, and more. Same things happen for chemistry, physics, and math.

This is exactly why nothing can exceed the speed of light. The mass of any spacecraft increases whenever energy (in the form of thrust) is applied to them, which would reach infinity when their speed is 1c, which means infinite amounts of energy is needed to reach 1c. At this rate, we'll never get out of the Solar system.

We have enough understanding about the physics and dynamics of gyroscopes to the point that we use them reliably as sensors in inertial navigation systems, and reaction wheels in satellites for attitude control. The science on gyroscopes evolved far earlier than rocketry, and there is little on them we haven't already know.

Which, assuming it could ever work at all, means using the Earth as reaction mass. While possible, I highly doubt that such a mechanism would be possible with today's technology, since ultra-fast gyroscopes require high-tensile-strength materials. Even then, it would probably work a lot like a classic wheel: the side that moves against the Earth being dipped in the outermost layer of the atmosphere, and the other side in the vacuum of space. Still, it uses the atmosphere('s outer layers) as reaction mass, so it would still be possible, though just barely.

this isn't really about perpetual motion, it's about changing an objects point in space without propulsion, and only through mechanical motion. don't picture it as some kind of spinning thing hurling through space, but rather more like a robotic arm methodically moving. No, he's right. In order to move using the OP's principles, the balls have to 'grab' something in space. Spacecrafts in orbit have practically nothing to grab on to, so they have to produce thrust via expelling reaction mass.

Launch an entire space station to orbit? I did it in KSP once, at least.

I think you've been reading a little too much Harry Potter today... I don't see why someone who can teleport himself anywhere he wanted with a little effort would be interested in space travel. Should there be a need to do so, however (such as needing materials only found on the Moon), they'd probably have their own solutions based on their magical capabilities. It may not be a rocket; a portal, for instance, could do the same job, if done correctly. If by fantasy, you included things other than wizards (as in man-and-monster stories), the possibilities are literally endless. There could be stories where people ran from monsters using rockets (similar to Dead Space games), or ones where space technologies flourish in a multiple-dominant-race world (similar to Star Trek/Star Wars, but from a single planet). Going even wilder would probably result in scenes such as warriors and soldiers pummeling dragons by deorbiting dead satellites and spent upper stages, or whole space programs similar in tech levels to current ones, but is done underwater entirely by some intelligent waterborne creatures we have never found. It definitely is possible to combine fantasy and sci-fi. In fact, science fiction itself is a type of fantasy. It just needs to be done correctly, and this requires generous applications of imagination.

Yes, the A2 in question was not suborbital. In order to use its high top speed, it has to fly over oceans or uninhabited territories, as supersonic flight over land is currently prohibited. For long trips such as London to Sydney, it had to go through The North Pole, over the Pacific Ocean, then arrive at Sydney from the north. Suborbital airliners were supposed to get over this problem by flying at an altitude where the air is too thin to transmit sonic booms to the ground, eliminating the need for unorthodox routes. As far as I know, current PDEs are mostly either small-scale hobby projects, or experimental engines. We have yet to build one capable of actually propelling an airliner-sized aircraft (though, at least there's one highly modified light aircraft, a Rutan Long-EZ, flying on such an engine). Also, PDEs still need atmospheric oxygen to run, so it would run into the same problem as a scramjet would: choked out of air at high altitudes. With enough TWR, they could provide the initial acceleration for the "hop", but it would probably be rather uncomfortable. Also, PDEs are quite noisy. From what I saw at Youtube, the things sounded like machine guns.

So are trains and airplanes. They are complicated, needs significant infrastructures, and presents engineering challenges. Yet, we build them anyway.

You mean the Quiet Spike?

Scramjets works only in an atmosphere. Once the plane gets to a critical altitude, where the air is too thin, it would stop working. In theory, if the scramjet's initial acceleration is powerful enough, it could also do the job.