nyrath

Yes. Except instead of accelerating a subatomic particle, it is accelerating a metric ton projectile.

This is wonderful that KSP is encouraging the youngster to imagine what other planets are out there. Building creativity is very important. I'm reminded of an old Dr. Seuss book called On Beyond Zebra, about the secret letters of the alphabet that are past the letter "Z" http://en.wikipedia.org/wiki/On_Beyond_Zebra!

The Hollywood misconception that really annoys me is that most spacecraft are laid out like a passenger aircraft, that is, with the direction of "down" at ninety degrees to the direction of thrust. In reality, the crew quarters of a spacecraft will be arranged more like a skyscraper than like an aircraft. You will feel like the direction of "down" is in the same direction the exhaust is going. Then comes the misconception that there is friction in space (turn off the engines and the ship slows to a stop, anybody who has played KSP knows this is stupid), that rockets are arrows (the ship MUST travel in the direction the nose is pointing, also quite stupid), and that space is two-dimensional like the surface of the ocean. http://www.projectrho.com/public_html/rocket/misconceptions.php (thanks for the link Specialist290!) But to answer the original poster's question: no, space fighters are not going to act like combat aircraft. The main reasons are here: http://www.projectrho.com/public_html/rocket/spacegunexotic.php#id--Space_Fighters--Efficacy The question is: why did Hollywood and science fiction writers ever get the silly idea that combat spacecraft would act anything like combat aircraft? My theory is that it is a comfortable metaphor.

Thank you for your kind words. But I still think that KSP does a far better job at rocket science education than my website will ever do. Please keep up with your project, and take careful notes on what aids and what hinders your daughter's progress. You saw this did you not? http://imgur.com/a/sW3Tz some students used KSP and some props to run a mission control simulation.

That's the reason KSP is worth its weight in gold. Without even noticing, your daughter is being taught to have an intuitive feel for astronautics, before she has even learned about fractions. She will be looked askance at by her friends and relatives when she starts talking about specific impulse and delta V. And that's a good thing. It is just like Wil Wheaton said:

Bravo Nikolai! Your daughter has given me hope for the new generation. She did it all by herself.

Well, there are a couple of problems. For space exploration, you want a high Isp engine. For space combat, you want a high thrust engine. An ion drive can reach up to around 210,000 seconds Isp, but you'll be lucky to get a miserable 10,000 newtons out of each engine (while a single Saturn V F1 engine can easily do more than seven million newtons). Maybe an ion drive can give you a much higher delta V, but it doesn't help you in combat if it takes a few months to accelerate up to speed. But the elephant in the room that nobody wants to talk about is the fact that anything a space fighter can do, a missile or drone can do better. For many reasons. Like the fact the drone can use accelerations that will turn a human pilot into a thin layer of red goo covering the back wall of the crew cabin. And the fact that the fighter has to carry fuel to delta V to transit to rapidly the target, delta V to match velocity with the target, delta V to transit back to the mothership, and delta V to match velocity with the mothership. A missile just has to carry fuel to delta V to transit rapidly to the target, period, because the missile does not have to come back home. If manned fighter only carried that little fuel, you'd soon run out of pilots. There are more reasons here: http://www.projectrho.com/public_html/rocket/spacegunexotic.php#id--Space_Fighters *Having said that* I know that space fighters are too irresistibly romantic for science fiction writers and fans to avoid. So please carry on with what you were doing.

Warscribe, hah, I scoff at your puny orbital scale melter. Relativistic weapons are the true terror weapons. If the projectile is travelling faster than 86.6% the speed of light, it does more damage than if it was made of pure antimatter. At 95% the speed of light, it does damage as if it was composed of three times its mass in antimatter. It does not matter what the projectile is made of, at those speed it makes no difference if it is composed of rocks, lead, raw sewage, or belly-button lint. An explosive warhead is superfluous. And as an added bonus, since it is moving at relativistic speeds, the defenders radar and telescopic tracking cannot see where the projectile is, only where it was. At such speeds, it will have the optical illusion of apparently travelling faster than light. The main draw-back is that the weapon firing the projectile has to expend the same amount of energy as the projectile inflicts. Actually it needs more energy, since the weapon is not going to be 100% efficient. This means if you are firing a one metric ton projectile at 95% c you'll need a bit more than 1.98 x 10^20 joules (about 300 times the energy of the Krakatoa volcanic eruption). For each shot. You might find entertaining this description of a relativistic attack: http://www.projectrho.com/public_html/rocket/spacegunexotic.php#id--Relativistic_Weapons--The_Killing_Star

Not only was the launching plane endangered by a 100 megaton detonation, such an explosion would have caused too much radioactive fallout. Too much fallout in the opinion of the Soviets. You know, the same guys who thought that the Chernobyl disaster did not release enough radiation that it was worth mentioning to the other nations in the region.

Ah, shucks. Yes, that's me. I'll have to "air sign" your shirt though. But I'm still convinced that KSP has done more for teaching astronautics than a zillion views of my website.

Yes, that is the one. I didn't want to toot my own horn. The Seal of Approval is here: http://www.projectrho.com/public_html/rocket/sealofapproval.php#id--Computer_Simulation--Kerbal_Space_Program

Well, the next paragraph in the Wikipedia articles says that if you use fission or fusion instead of a coal fired plant they are more efficient than using a steam powered turbine. https://en.wikipedia.org/wiki/MHD_generator#Generator_efficiency

Orbiter is awesome, but comparing it to KSP is apples and oranges. Orbiter is all about learning how to pilot. The only way to create your own ships is by the equivalent of making a Kerbal mod. Kerbal is educational about rocket design. And about piloting. You can make your own ships by assembling modular parts within the game, no mods required. A minor point is that there are absolutely no weapons in Orbiter. The developer forbids it. But I've seen a few weapons in the Kerbal mods repositories.

Keeping in mind that Bussard Ramjets have a terminal velocity (unless they are using magic tech). This is reached when the relative velocity of the incoming hydrogen equaled the drive's exhaust velocity. Drag from the scoop, you see. This means a proton-proton fusion Bussard Ramjet would have a maximum speed of 12% c. Unless you can figure out a way of inducing the scooped hydrogen to undergo fusion Without Slowing It Down First. Which is magic tech. I have a few hyperweapons listed on my web site http://www.projectrho.com/public_html/rocket/planetaryattack.php http://www.projectrho.com/public_html/rocket/spacegunexotic.php

Hi! I'm the author of the Atomic Rockets website. I deeply apologize for taking so long to award Kerbal Space Program with the Atomic Rockets Seal of Approval. I had looked at the program a long time ago, but back then my computer was so antiquated that it really could not run the program. Just recently I got a better computer and I tried KSP again. I am totally dumbfounded at the elegance of KSP. It is the most astonishing educational astronautical software I have ever seen. Players get an intuitive feel for many rocketry concepts and constraints. Plus the addictive nature of the game keep players coming back for more. Much better at teaching than, say, Orbiter. I'm still a rank beginner at playing the game, but that will change.

Yes, I agree with everything that has been said. But for the original poster, just in case it was not clear: relativisitic time dialation, mass increase, and length shortening is a consequence of making the assumption that the speed of light in a vacuum is constant for all observers in all frames. Once you make that initial assumption, the other phenomenon are forced to occur by the logical consequence of how the laws of physics interact.

Using spin is the best way to generate gravity (since micro-black holes are in short supply). Spacecraft can spin around their roll axis, or either the pitch or yaw axis (the latter is called a "tumbling pigeon"). Or as the original poster said, separate the ship into two parts connected by a cable. Why? Crew nausea. Centrifugal gravity strength is related to the spin rate and the radius of spin (equation here: http://www.projectrho.com/public_html/rocket/artificialgrav.php ) If the spin rate is above 7.5 rotations per minute, the crew will become nauseated. With that as a limit, the only way to increase the strength of the centrifugal gravity is by increasing the spin radius. And the most low-mass way to do that is by splitting the spacecraft in two connected by cables.

The point is that you can design a mass driver so that what it accelerates is a magnetic bucket. You load the bucket with rocks, used baby diapers, belly-button lint, old AOL CD-ROMs, or whatever spare mass you have. The bucket is magnetically accelerated coilgun fashion. At the end of the driver, the bucket is braked to a halt, and the bucket contents go whizzing off into space. When used for propulsion, typical figures I've seen say a representative model would require about 350 megawatts, engine mass about 150 metric tons, thrust about 20,000 newtons, specific impulse about 3,000 seconds. The attractive part is that you can use any mass for propellant. So an asteroid miner could land one on a valuable asteroid, and use the mass driver to alter the asteroid's trajectory. Naturally the astromilitary of the various spacefaring nations will have their warships closely monitoring this, so no evil person or nation covertly alters an asteroid's orbit to strike Earth (or Kerbin) or to take out a space station or something. Mass drivers can also be used for transport, this was how they were designed originally. You site one at a mine on Mün which produces titanium or aluminium. You use the mass driver to send blocks of ore into orbit to the future site of a huge L5 orbital colony. A "catcher" at the site intercepts the ore, which is then refined into structural members for the colony. You go to all this trouble instead of sending the structural members up from Kerbin because of the insanely high delta-V cost to boost into orbit.

Actually there is a better way to convert fusion released energy into electricity than using the inefficient boiler system used by fission reactor. You can send the plasma from the reaction through something called a "magnetohydrodynamic generator" (MHD generator) and get electricity out of it. Look up MHD generator in Wikipedia.

Kryten agreed, cryogenic fuels are a pain. I've seen lots of proposals for orbital depots carrying cryofuels, they have lots of foil umbrellas to shade from the sun, and absolutely none of the proposals has actually been created and flown. But astronautical people are working on them, because such depots are the key to opening up the solar system. The ability to refuel at your destination drastically cuts your spacecraft's required mass ratio, so you no longer have to make your tanks out of metal foil and your structural members out of metal soda straws.

I know I'm being pedantic, but what the original poster is describing is an "ion coilgun", not an "ion railgun". And Rune is absolutely right, it has been thought of before, and it has problems.

I agree with Nibb31. Media science fiction is pretty silly when it comes to depicting how orbital combat will appear. The great thing about KSP is that you can actually experiment with orbital combat and find out first hand what works and what does not. I've gathered some information on the topic on my website, in the following pages http://www.projectrho.com/public_html/rocket/spacewarintro.php http://www.projectrho.com/public_html/rocket/spacewardetect.php http://www.projectrho.com/public_html/rocket/spacegunintro.php http://www.projectrho.com/public_html/rocket/spacegunconvent.php http://www.projectrho.com/public_html/rocket/spacegunexotic.php http://www.projectrho.com/public_html/rocket/spacewardefense.php http://www.projectrho.com/public_html/rocket/spacewarship.php http://www.projectrho.com/public_html/rocket/spacewartactic.php http://www.projectrho.com/public_html/rocket/planetaryattack.php

Well, as others have already pointed out, the real question is why would one want a future frigate to hover in the atmosphere in the first place? The main reason seems to be "because that's how scientifically illiterate Hollywood portrays spacecraft". As NASAFanboystated, it makes far more sense for a frigate to stay in orbit and send down landers and/or fighters. After playing KSP for a while one realizes the hideous amount of propellant required to send each gram of mass into orbit. Why should a frigate waste huge amounts of propellant and/or energy to enter the atmosphere, hover the way bricks do not, and climb back to orbit? All the time making itself a huge target for any hostiles on the planet. A case might be made for a huge ship to land combat troops and armored vehicles, but that sort of craft has no intention of hovering. Again: hovering makes you a target. The higher you hover, the more enemy units that can target you. It does not matter if you have some sort of unobtanium that allows hovering, the reality is that it is counter-productive. Outside of science fictional magic tech, it makes more sense to have: Surface to Orbit shuttles Orbit to Orbit ships Airless-planet landers http://www.projectrho.com/public_html/rocket/advdesign.php#id--Types If you have combat on your hands, some of the Orbit-to-Orbit ships will be optimized as warships. http://www.projectrho.com/public_html/rocket/spacewarship.php Inside of science fictional magic tech, you are free to make up any handwavium or technobabble you want. If you want to do the job correct, you will avoid technobabble, and try to figure out the unintended consequences of your postulated handwavium. http://www.projectrho.com/public_html/rocket/prelimnotes.php#id--On_Shaky_Ground http://www.projectrho.com/public_html/rocket/respectscience.php#id--Unintended_Consequences