realistic spaceship combat

[Sikander]

Originally posted by The diplomat


Yes you would have a recoil effect because of the law of conservation of momentum. This would make rail guns on spaceships highly unlikely because the recoil would be too much. You could however, have rail guns on planets, since there the recoil would be regligeable.

They might actually be pretty useful for running away and discouraging pursuit, as any momentum from the "rear" of the ship would simply increase the speed of the fleeing vessel while laying down some fire on the pursuer. Otherwise I agree with your analysis.

[Sikander]

Originally posted by chegitz guevara

Recoil can be taken nito account. Modern ships have to deal with it, no reason to believe it would be a major detriment to space ships. On top of that, missiles will cause recoil also.

I disagree. Firstly, the lack of friction in space means that every bit of energy put into the rail gun is going to have to be equalled by the engines if you want to maintain a consistent speed while converging on the enemy. Conversely if you are fleeing, rail guns would actually help speed you on your way, assuming that this doesn't push the ship across some sort of G-force barrier that incapacitates the crew, or in an unmanned ship damages or destroys the ship itself.

All a missle has to do to be momentum neutral is detach itself from the ship before it engages its engine.

[Colonâ„¢]

Originally posted by DRoseDARs
While oxygen fires aren't possible in a vacuum, other chemical reactions are, such as liquid hydrogen and liquid oxygen being fused at the business end of the Space Shuttle as it goes through the oxygen-poor environment of Earth's upper atmosphere. The force of the two elements fusing is directed out the back of the shuttle, but at the same time it presses against the inside of the reaction chamber, pushing the shuttle ever upward.

But you can only use this in the orbit of a planet right?

Beyond simple chemical reactions, it may very well be possible to harness the incredibly small force of photons (light) pressing against a reflective surface. Tests have already succeeded in levitating small objects with nothing more than highly-focused lasers. On a larger scale, gigenormous "solarsails" could harness the photons streaming out in all directions from our sun. Although gradual, over time the cumulative force of all the photons hitting the sail could conceivably accelerate the solarsail to near-light velocity (ignoring for a moment the physical stresses on the structure, debris in its path, and time necessary) without expendature of any other form of propulsion.

Doesn't seem very practical in space combat though.

But can you also reverse-thrust this way?

[Sikander]

Originally posted by chegitz guevara


Then they'd have to be carried externally, where they would be suceptable to debris. Things don't "drop" in microgravity. You could, however, give the missile a slight nudge, and it could fire when away from the ship. Even that, however, will cause recoil, just at a much lower strength.

Simply fire them in pairs away from the ship on opposite sides.

[DRoseDARs]

Originally posted by Colon
But you can only use this in the orbit of a planet right?

No, not necessarily. Remember that we've sent dozens of probes to other points-of-interest in our solar system. Although the cost most of the way there, some have decelerated near their targets in order to be captured by its gravity, establishing an orbit around it. I'm not certain if solid perpellents or other chemical reactions were used or which missions. One probe used the upper atmosphere of Mars in order to slow down and be captured, using little or no propulsion in the maneuver. Just atmospheric friction.

Doesn't seem very practical in space combat though.

True...

But can you also reverse-thrust this way?

One application, which will probably remain in the realm of theory and never application, is sending a solarsail from our system to a nearby star. By manipulating the geometry of the sail upon arriving in the target system, the force of that star's photons would serve to slow the sail. It really isn't all that different from traditional windsails when you think about it.

[Hurricane]

Rail guns could be good for short range combat, or perhaps more probably, as a missile defense system (just like on today's aircraft carriers). You have to remember that is is extremely hard to hit anything other than a target moving straight towards (or away) from you if you also are on a moving platform. And the low-gravity space, making quick avoiding and course-change easier, makes things even harder.

[Colonâ„¢]

Originally posted by DRoseDARs
One application, which will probably remain in the realm of theory and never application, is sending a solarsail from our system to a nearby star. By manipulating the geometry of the sail upon arriving in the target system, the force of that star's photons would serve to slow the sail. It really isn't all that different from traditional windsails when you think about it.

Yes but can you also turn around like that? Those sails seem very sluggish to me.

Neither does it seem very practical for small fighters and the like.

Is there any way to harness photons by other means than sails? (even if it's purely theorethical)

[Sikander]

Crap, I really should read the whole thread before responding. Sorry.

Sensors: Optics would work very well for unobstructed views into deep space, while radars etc. would be useful for peering into and through more "cloudy" areas like planetary orbits and such. Drones could be used to supply active views of space while not giving away the positions of your ships, assuming that they are not emitting from all 360 degrees, but leave your ships in the "dark".

Ship design: It seems like long thin ships with stealth materials on the nose would be best for remaining undetected. They could either turn broadside to deliver a greater amount of firepower once combat is initiated, use missles that detach from the sides of the ship before they kick in their missles. At first it seems likely that there will be little defense, and thus detecting the enemy first will likely result in a kill. Later, more though will have to be given to increasing the maximum firepower of the ship. Aerodynamics will be of no importance. You could build a needlelike ship (to reduce cross-section and avoid detection) that could reconfigure itself into a plane facing the enemy to maximize firepower for instance. That assumes that you have enough confidence in that firepower to risk becoming a huge target for a while.

Defenses: With nuclear missles being thrown around this will be problematic. Of course you could send some nuclear missles of your own ahead of your ship (ie toward the enemy) a safe distance which could be set off to defeat enemy missles in the no man's land between opposing ships. Kinetic weapons would be effective, but their range would have to be pretty short. They wouldn't lose much energy at long range, but they would be easy to dodge without maneuvering thrusters of their own. These could be destroyed before they got too close by nuclear missles, assuming that your ship was maneuverable enough to dodge the debris heading its way.

[DRoseDARs]

Originally posted by Colon


Yes but can you also turn around like that? Those sails seems very sluggish to me.

Neither does it seem very practical for small fighters and the like.

Is there any way to harness photons by other means than sails? (even if it's purely theorethical)

Perhaps I should try a different way of explaining. Here's a way you could simulate the sail principle I'm talking about:

Get a shallow container, like a retangular cookie pan, and fill it with water. Place a float (maybe a soda cap with a piece of paper as a sail) at one end of the pan. Lightly blow the float towards the opposite end of the pan. As it approaches, go to the other side of the pan and again blow air at it, this time in an attempt to slow and stop its approach.

The analogy is that you play the role of both the originating star system and the target star system. The air you blow is the force of photons and of course the float is the solarsail. So yes, you could journey in this fashion, similar to sailing the ocean blue.

And you're right, solarsails would make awful combat ships. Not to mention battles would be veeerrry slllooow as the ships try to move around...

Could photons be used in means other than propulsion? I'm not an expert by any means, but I believe lasers are simply photons that have been excited into certain energy states by specific catalysts (<- things that cause other things to happen ). Lasers are photons travelling in highly-focused streams, with every particle moving exactly in the same direction.

Lasers have been tested for weapons applications and have succeeded...to an extent. The US has been trying to develope a Anti-Ballistic Missile defence system, partly involving lasers. They are trained on a target, like an inbound ICBM, and cook it until its fuel heats enough to go boom, long before the missile reaches its target.

[DRoseDARs]

A couple of people have mentioned use of nuclear weapons in space. My feeling is this would be a bad idea for close-quaters combat. Longer range combat might be ok, but you'd have to detect the enemy and calculate his position at the projected intercept point before launching. The further away you are, the harder it is to do this 'cause the distance gives your target time to detect the attack a perhaps move out of range or deploy counter measures. Closer range combat would increase your own risk as you'd be nearer the explosion, which would radiate out in all directions regardless of who fired the missile. You'd be at risk of both the EM pulse and the radiation.

[Colonâ„¢]

Originally posted by DRoseDARs


One correction before I answer: Not PROtons, but PHOtons. Important difference: protons are one of three particles that make up atomic elements, while photons are free particles in their own right.



Perhaps I should try a different way of explaining. Here's a way you could simulate the sail principle I'm talking about:

Get a shallow container, like a retangular cookie pan, and fill it with water. Place a float (maybe a soda cap with a piece of paper as a sail) at one end of the pan. Lightly blow the float towards the opposite end of the pan. As it approaches, go to the other side of the pan and again blow air at it, this time in an attempt to slow and stop its approach.

The analogy is that you play the role of both the originating star system and the target star system. The air you blow is the force of photons and of course the float is the solarsail. So yes, you could journey in this fashion, similar to sailing the ocean blue.

And you're right, solarsails would make awful combat ships. Not to mention battles would be veeerrry slllooow as the ships try to move around...

Could photons be used in means other than propulsion? I'm not an expert by any means, but I believe lasers are simply photons that have been excited into certain energy states by specific catalysts (<- things that cause other things to happen ). Lasers are photons travelling in highly-focused streams, with every particle moving exactly in the same direction.

Lasers have been tested for weapons applications and have succeeded...to an extent. The US has been trying to develope a Anti-Ballistic Missile defence system, partly involving lasers. They are trained on a target, like an inbound ICBM, and cook it until its fuel heats enough to go boom, long before the missile reaches its target.

Yes, I know we're talking about photons. That was a typo I had already corrected before you replied.

And I actually meant to ask whether there's any other way to use photons as a propulsion, other than sails.
Do those highly focused lasers you mentioned have a lot of potential for a more agile means of propulsion?

[DRoseDARs]

Originally posted by Colon


Yes, I know we're talking about photons. That was a typo I had already corrected before you replied.

I'll fix mine to reflect that in a moment.

And I actually meant to ask whether there's any other way to use photons as a propulsion, other than sails.
Do those highly focused lasers you mentioned have a lot of potential for a more agile means of propulsion?

Well, with the lasers the main idea I've heard is to use huge satelites to collect sunlight and focus it into a much tighter beam (microwaves I believe). This beam would then be directed at the business end of a modified solarsail. Think of it as going from a passive sail to a mud-bogger(?) (one of those boats with the big fan on the back). Would wouldn't rely on the gentle nudge of the sun to speed up to your target, instead you'd get a stronger shove from a concetrated beam. I forget what you'd do once you got to your target...

[Colonâ„¢]

Originally posted by DRoseDARs
re: Propulsion
Well, we've already designed, built, tested, and used Ion drives. They require far less fuel than traditional chemical rockets. Combined with modest nuclear fission, or preferably fusion, powerplants they should be reasonably effective at moving ships through space. Using magnetically charged conduits, drive plasma might even be used for attitude adjustments, further lessening reliance on chemical reactants. Before you say that Ion drives that have been used are very slow, bear in mind that these probes are little larger than breadboxes (<-cliche for those that missed it). Their powerplants have to power the engines AND instruments AND communications. A larger vessel might have room enough for multiple powerplants dedicated to different subsystems.

Sorry, I totally missed this post. These can also be used for thrust in space, right?

[Colonâ„¢]

Besides, anyone considered the danger of a "stray bullet" in space? On earth, when you're at a large distance from a battlefield, you're usually safe from stray bullets. (although missiles have increased the danger) But in space a stray bullet could hit a target lightyears away. I wouldn't want to know what happens if you start firing nukes in space.
And what when you use missiles that accelerate? If such a missile goes astray it could end up hitting something (eg a planet) at enormous speed.

[DRoseDARs]

EDIT: I was too slow in posting this. This post reponds to the one before the one above.

Yeah, the first such probe was launched a few months back...maybe even back in 2001, I can't remeber specifics anymore. I think its primary mission was an asteroid/comet that passed near Earth. The Ion drive was just added to see if it would work. I believe it did quite well.