Both fission and fusion appear promising for space propulsion applications, generating higher mission velocities with less reaction mass. This is due to the much higher energy density of nuclear reactions: some 7 orders of magnitude (10,000,000 times) more energetic than the chemical reactions which power the current generation of rockets.
Very briefly Getting to space requires that the payload reach orbital or escape velocity. Maximum energy over a short period of time. This challenge has been met today by the various chemical rocket motors out there.
If you haven't already, I suggest checking out this website thouroughly: http://www.projectrho.com/public_html/rocket/index.phpIt has a lot of information on the basics of space travel and the not-so-basics of space travel with advanced propulsion systems.However, if you REALLY want a good intuitive understanding of space travel and orbital mechanics, I suggest buying and installing Kerbal Space Program. It'll let you build rockets and control them yourself to get som hands on experience, while providing lots of entertainment and explosions along the way. It makes some simplyfying approximations and strongly overestimates hardware reliabillity, but the physics are accurate and you'll learn a lot from it. You can buy it on their website or on steam.It's mostly focused on chemical propulsion with the only exceptions being an Ion engine and a NERVA-like Nuclear thermal engine, but there are mods to add in more speculative types of engines if you'd like. However, I strongly suggest playing with the stock game parts to begin with, as too powerful parts might ruin the gameplay to some extent as they can make the game too easy.
One of the main problems with getting up into space other than cost problem is fuel!! Getting in space 90% to 95% of the rocket is just fuel to get that small 5% payload up there, current rockets are multi-stage clamber to reach orbit. The fuel packs just enough of a punch to make the trip at all!!!!!! It uses fuel like drunken sailor!!!!!I was saying they need to research other fuel sources that is more fuel efficient.Some people where saying that may not be possible because of limitations imposed by chemistry on rockets.
CHEMICAL fuels, where energy is stored at the bonds BETWEEN ATOMS AND MOLECULES which are at their limit before becoming unstable.
The problem with chemical rockets is they have very low specific impulse around 400.That means they only operate for only a few minutes before all the fuel is gone.The highest specific impulse ever achieved for a chemical rocket was around 500 using Hydrogen ,Lithium and Fluorine.But was ridiculously hazardous and very challenging.And never will be used again because it is very hazardous and very dangerous.Trying to get chemical rockets to operate on higher specific impulse around 500 or 600 or higher is just too hazardous and very dangerous.It becomes too hot and wants to explode and thus you need new strong rocket material and think rocket.Well Ion engines and Plasma engines have very high specific impulse but very low thrust so would never take off from earth and bust be use in space only , not taking off from earth.Other option for even higher specific impulse are Fission rockets or fusion rockets that have a reactor to heat a gas and blast it out the back.But the rocket would probably explode because the thrust is too high.
I was not really asking how all these propulsion systems work.What I seem to be confused about is the laws of chemistry apposed on rockets.
.. grasp of even the most basic principals. You also have grammatical problems in your posts .. principals of chemical rocket propulsion, among others.
Well Ion engines and Plasma engines have very high specific impulse but very low thrust so would never take off from earth and bust be use in space only , not taking off from earth.Other option for even higher specific impulse are Fission rockets or fusion rockets that have a reactor to heat a gas and blast it out the back.But the rocket would probably explode because the thrust is too high.
Quote from: nec207 on 05/27/2014 04:52 amI was not really asking how all these propulsion systems work.What I seem to be confused about is the laws of chemistry apposed on rockets.I think the reason people are pointing you to information on the fundamentals of rocketry and physics is that you don't seem to have a grasp of even the most basic principles. You also have grammatical problems in your posts, and the result of all of that is that it's hard to even tell what you're talking about.For example, in the two sentences I quoted above, it's hard to tell what you mean. The first sentence seems to imply you are saying you understand the basic principles of chemical rocket propulsion, among others. The second sentence seems to be you saying you are confused by the laws of chemical rocket propulsion.
I did some reading today and don't know if I'm interpeding it right but saying generally been a trade-off between high thrust and high specific impulse. You can have one at the expense of the other, but not both. An exception would be nuclear pulse propulsion where exploding nuclear bombs behind the ship to propel it.So in way saying no you cannot have high thrust and high specific impulse it is normally one or the other not both.
The idea that improving launch rockets significantly beyond the state of the art would involve unacceptable hazards and difficulties only applies to chemical rocketry, because the reason for it is that the chemicals you'd need to use are dangerous.For example, using fluorine instead of oxygen in a hydrogen-fueled rocket could improve performance substantially, but fluorine is horribly poisonous and hard to handle, and the exhaust would be hydrofluoric acid instead of steam. Ozone would be good too; unfortunately it is also very poisonous, and it tends to decompose spontaneously (and exothermically) even at moderate concentrations in LOX. The problem is specifically the chemicals, not the heat and pressure they generate in the engine.This has nothing whatsoever to do with fission, fusion, airbreathing, or any other method that isn't a chemical rocket. Such methods have different problems, which are potentially surmountable.
I was saying they need to research other fuel sources that is more fuel efficient.Some people where saying that may not be possible because of limitations imposed by chemistry on rockets.
Quote from: nec207 on 05/27/2014 06:59 pmI did some reading today and don't know if I'm interpeding it right but saying generally been a trade-off between high thrust and high specific impulse. You can have one at the expense of the other, but not both. An exception would be nuclear pulse propulsion where exploding nuclear bombs behind the ship to propel it.So in way saying no you cannot have high thrust and high specific impulse it is normally one or the other not both.That is only true for some engines, like Ion engines. It is not true for chemical engines. Actually, AFAIK, it is actually the opposite for chemical engines, although it does not have so much impact as with Ion engines.
Ok,Simple answers.Chemical rockets have an upper limit as to how fast they can go with a given amount of fuel.Ion Rockets can go really fastwith very little fuel but don't put out a lot of thrust initially and take a LONG time to get up to speed. (Not powerful enough to lift of the planet.)The idea behind Fission and Fusion rockets is to get the fuel REALLY hot so it expands faster than the fuel from a chemical rocket would. The advantage here is that you can get a lot of thrust for a much smaller amount of fel than it would take for a chemical rocket, (Good for boosting to orbit), and once in space, it could give a big initial push and be throttled back for a continious thrust, similar to the Ion engine.Problem is, Fission engines require a nuclear reactor which will involve radioactive materials. An accident could contaminate a large area. And we haven't quite figured out Fusion Rockets or reactors yet, but there's been some very promising developments on this over the last year or so.Anti-matter could take a mass of anti-matter about the size of a quarter and slowly combine it with an equal amount of matter and produce enough thrust to go ANYWHERE in the solar system in a few weeks, under a continious thrust. Problem here, we still don't know how to make large quantities of anti-matter and haven't quite licked the problem of containing the antimatter for storage, let alone trickle it out as a fuel source.Hope this tells you what you wanted to know.
It's not complicated, there's only so much energy you can get out a chemical reaction.LOX/LH2 is almost as good as it gets, and the things that could theoretically give higher performance all have major drawbacks. There is really no chance of something dramatically better coming along.