Nuclear fission rockets are becoming obsolete and have been superseded by the more efficient antimatter engines, which have nearly 100% efficiency and do not produce pollutants.
I'm wondering this: in a space battle that takes place within the solar system, is there any place for nuclear powered spaceships, or do they belong in space museums?
In wartime, quantity is a quality of its own. You do not need ideal weapon during war time. You just need more of it than your enemy.
Given that:
You should be able to build, and fuel, more fission powered ships which will give you an edge in combat.
However I'd suggest adding fusion to your list of reactors, as it should be a stepping stone between fission and antimatter annihilation.
(A couple options -- feel free to use either or both!)
Antimatter is really finicky about how it's contained. High-G combat maneuvers and delicate magnetic bottles are not friends, and even a minor bit of battle damage to the bottle is an all-but-guaranteed loss of ship with all hands. Fission is much easier to keep stable in combat, and containment wobbles or damage have much less catastrophic failure modes.
Antimatter drives are far more expensive compared to fission drives. So they're fine for something like a capital ship, carrier, or large transport, but smaller, short-range craft like tenders, shuttles, and fighters, and especially expendable craft like drones or missiles, still use much cheaper fission drives.
Yes, I think that there might be no nuclear fission powered ships, but nuclear fusion ships will still be there. Or maybe there will be hybrid ships that can run on fusion or annihilation.
The reasons:
Nuclear fission rocket is becoming obsolete and is superseded by the more efficient antimatter engine, in fact there will be no pollution and the efficiency is around 100%.
Unfortunately no.
Firstly, you can you create your antimatter. The pesky law of conservation of baryon number means that in most cases your maximum efficiency of antimatter creation will be 50%, because for every antiparticle your energy-to-mass system coughs up, you'll also get a corresponding normal particle. In practice, even a 1% efficiency would be astonishingly high. You'll need a vast and expensive infrastructure for antimatter synthesis.
Secondly, a 100% efficient conversion of energy release from annihilation into kinetic energy of exhaust products is basically impractical, and not just becasue thermodynamics hates you. About 33% of the annihilation energy will be in the form of neutral pions which will almost immediately decay into highly penetrating gamma rays. It will be Quite Difficult in most designs of antimatter engine to absorb those gamma rays into your reaction mass and have a high thrust engine, and in any design it will be impossible to both absorb all the gamma rays and have a high specific impulse (roughly: fuel economy). You'll get at most ~80% efficiency for a solid core antimatter engine, which will have a performance and Isp equivalent to a solid core nuclear rocket.
Thirdly, whilst your antimatter engine is running it will be kicking out, at a minimum, a lot of gamma rays. More complex designs with higher exhaust velocity will also spit out various kinds of interesting and unstable light particles which will themselves cause some issues but also eventually decay to gamma rays. Once the engine is turned off there will be a lot less residual radiation, but there will be some. A single antiparticle hitting a large nucleus (such as the tungsten core of a solid core antimatter rocket) will not annihilate the entire atom, but will transmute it and maybe even fission it. The resulting nuclides are not guaranteed to be stable!
It is at least a lot more plausible (and an awful lot safer) to use a solid-core antimatter rocket to lift off from Earth than to use a nuclear rocket of any kind. You need so little antimatter for the job that even a worse-case catastrophic accident will be quite non-destructive and there will be no fallout to be concerned about.
I'm wondering if in a space battle that takes place within the solar system is there any place for nuclear powered spaceship or they belong in space museums?
Nuclear rockets are a lot less versatile... not only are they more hazardous to maintain, but they can't be trivially turned on and off at will. This is fine for civilian purposes (where you will do be doing a couple of orbital injection burns at the start and end of your journey), or if you are making a torpedo, but it is slightly more inconvenient for a warship.
Their fuel on the other hand is almost certainly cheaper to obtain and simpler to store and a lot safer to be around once high-power weaponry starts going off in the neighbourhood.
The efficiency of antimatter is slightly less than you might think. It is up to you to determine the relative availability of antimatter vs fission fuel, which will ultimately tip the balance in favour of whichever outcome is best for your story, and we can't determine that for you!
Well, someone during WW2 used bow and a claymore
John Malcolm Thorpe Fleming Churchill, DSO & Bar, MC & Bar (16 September 1906 – 8 March 1996), was a British Army officer who fought in the Second World War with a longbow, bagpipes, and a Scottish broadsword. Nicknamed "Fighting Jack Churchill" and "Mad Jack", he was known for the motto: "Any officer who goes into action without his sword is improperly dressed."
In May 1940, Churchill and some of his men ambushed a German patrol near L'Épinette (near Richebourg, Pas-de-Calais). Churchill gave the signal to attack by raising his claymore.
Though not a large scale usage, someone can be nut brave enough to stitch to the good old way of fighting just for the sake of preserving traditions.
Check this link for a fusion-powered spaceship that could be ready in the next decade. The Direct Fusion Drive (DFD) engine could take flight for the first time in 2028 or so. The minivan-size DFD could get a 10,000 kilogram robotic spacecraft to Saturn in just two years, or all the way out to Pluto within five years of launch.
Such a spacecraft would be a far better alternative than a fission-powered craft, and it is less dangerous than an antimatter drive, where storing the antimatter safely is a major issue. It uses deuterium and helium-3, and while the latter is pretty rare on Earth, it is fairly abundant in space, e.g. on the surface of the Moon, and it can be produced in fission reactors. The reactor/engine is fairly compact, as the reactor chamber can't be more than ca. 1.5 m in diameter. Because of this restriction in size, you will need several engines on a single spacecraft (6 is the estimate for a manned mission to Mars).
Antimatter will almost certainly not replace fusion because the fuel is simply too expensive to synthesize despite the efficiency. What is probably a better idea is antimatter induced fusion, if fusion power is too hard to make work otherwise.
While antimatter is 259 times as efficient as Detuerium-Helium-3, and while antimatter rockets have a theoretical exhaust velocity that is light speed, meaning that this is the upper limit on delta-v (rocket efficiency is mostly a function of exhaust velocity, with about double effective exhaust velocity a good practical limit for rockets when dealing with lower velocities not factoring relativity into account), they are not nearly as efficient as they seem.
Let's just assume that we can handwave over the problems and have a kind of crystalline magnetic bottle of anti-hydrogen (it will still explode if it ever loses power, so hope you have good batteries). Even with this, there are two big problems you can't get around.
The first is that 40 percent of the energy from antimatter becomes gamma rays, which are hard to harness and require heavy shielding. If you then tried to harness the antimatter reaction to create a plasma rocket, you would reduce your effective exhaust velocity down to 30% of light speed because of inefficiencies in magnetic nozzles. Your best bet with antimatter is actually to create a photon rocket, also known as a flashlight drive because it really is just a beam of light. This ups your exhaust velocity up to about 50%.
So, while it is possible to build an antimatter rocket, it will never have the cost efficiency of fusion power because it doesn't actually generate energy, it only stores it. Because there are no known natural sources of antimatter, it must be created artificially. It currently takes ten million times as much energy to create a unit of antimatter as that unit of energy is worth. Even with something like solar power stations around Mercury, the energy will almost certainly never be as cheap as the alternative of fusion.
So, if you're talking about using external energy, I'd say there is a better approach than antimatter. A better use of the energy is to create beam rider spacecraft. Either laser or magnetic/electric sails are a better option. Lasers are probably easier to make and more efficient over distance, but are also much more effective as weapons(known as the Kzinti lesson), which makes it easier to sell designing shorter ranged microwave installations for magnetic sails.
Nonsymmetrical warfare.
When nationstates go at it hammer and tongs, they use the most modern and advanced ships they can build or buy.
When the Federation battles the Pirate Loonies, however, the latter can't afford antimatter ships...but old, leaking, space-rusted fission ships are just the ticket. In fact, they refit fleets of the old monsters with autocontrol circuits, remove the shielding, and send them on suicide missions, irradiating everything they get close to before the self-destruct cycle.
A space propulsion system doesn't have an efficiency, it has a certain amount of thrust, and it can produce a certain amount of deltaV, and for a fixed power level you can trade of deltaV for more thrust.
This means even with antimatter powered spacecraft, you can still build defensive nuclear craft that may not match them in operational range, but can produce the same amount of maneuvering thrust in actual combat. Alternatively, nuclear drives may be a cheaper or more compact propulsion system for range limited expendable munitions.
Further, for any real nuclear drive (that includes fission, fusion and antimatter) the primary issue is managing the heat, so the higher energy density of the fuel may not be that much of an advantage.
You are possibly thinking only about troop transportation. If you are willing to go kamikaze, and also for missiles, nuclear powered engines have the advantage of causing +5 radiation damage to the target. So even if the enemy spaceship is not destroyed, its crew is now growing extra limbs and glowing green.
