nice idea, very good!

too bad it seems like a good fit for entrenchment.

Makes me think back to the Ground Batteries, Missile Base, Fighter Garrisons (Stelar Converter! gehehe ) and other such structures you could build on a planet's surface in Master of Orion II that worked alongside the Starbase you built in orbit to defend a planet (planet shield generators were built on the surface as well.) It makes sense to have developed additional ground based planetary defences, I agree, after having been at war so long.

Ron hit the nail on the head.

You're really far /far/ better off just putting defenses in orbit.

Those missiles are the size of skyscrapers in order to put small space craft into orbit, can be seen from space when they go off, and take a hell of a long time to get up there.  The fuel requirement to move something from the surface to orbit is massive, it's not a good weapon system.

what about ion cannons or the hypervelocity gun  like in star wars

Just a thought, but is it possible to use abilities?  Like the missile battery ability and place it in the planet ability slot, and have it auto activate and use it?   I have tried "some" abilities in the planet ability slots, but without success, but certainly it may have been i was not using an ability that was compatible.

Just an idea as it might make a least a "cosmetic" appearance of the planet defending itself with planetary defenses.

-Teal

p.s.  I will give this a try and let you know, unless someone has already done this and knows for sure it will or wont work.

Well.

In the tech setting that sins it is, beams are the only viable option for ground based defenses. Even today you can shoot Lasers into space.

However to put enough energy into that beam to

A.)  Compensate for the losses along the way due to the atmosphere

B.) Still have enough power in it to actualy do anything wortwhile

the planeta would have to have a massive power generation - in the ludicous scale of things.

In terms of gameplay, i do not think planetary defenses will "look good" .

Tiny planet shooting comparably large ships... nah.... would look awkward.

Why do people think planetary weapon systems are unrealistic? First the traveling system is unrealistic phase space traveling has no justification scientifically and nothing currently understood could explain it. So you are using double standards when claiming unrealism.

The next problem is the fact that the setting is thousands of years in the future so it would be silly to assume the weapons would use exactly the same mathods we use now.

The justification is quite easily made because unlike other aspects of sins it is realistic. For one missiles would be great planetary weapon system for defense.  To get the missiles in orbit you could utilize more efficient and high powered thrust systems. You could use a mass driver (think railgun but different) to launch missiles high up and the missiles activate after the kinetic energy slows from gravity. A laser with enough power could go through the atmosphere. With advanced power sources and better laser technology their is nothing unrealistic about it.

An alternative pure defense system would be anti missile/anti-projectile systems like a laser to destroy kinetic rods (Advent) or anti missile missiles (TEC).

If you want unrealistic aspects i find it funny nobody mentioned the innacurate weapon systems and ranges or strike craft. The TEC weapons would be horribly useless in reality. Guns and railguns would be only useful against incoming missiles or meteroids for protection. IN likely space combat the ranges you would fight in would be so huge that they would basically be entirelly worthless for offensive purposes. Advent lasers and plasma weapons would have much much longer ranges then they do in the game. The advent would essentially kill the others before they even got within a fraction of the distance needed to close with their ships. Strike craft essentially wouldnt exist except maybe in the Advent form as remotely controlled drones that stay close to a ship and protect it.

I guess I failed to make my point properly: assuming you have the technology to build 'planet based' weapons... they'd be a heck of a lot more effective in space!  For any given technology, it's going to be more effective to use it from space than from ground, simply because it avoids the atmosphere / gravity restrictions that way, and can be more effectively defended by making it mobile.  (Anything on a planet is going to be a sitting duck when a ship sends an asteroid or a missile flying it's way).  While it would allow you to make use of the planetary power grid -- potentially speaking, that's going to be a lot of power compared to your fleet's power supplies -- you're still looking at a much more vulnerable weapon, located in a place you're trying to protect, not focus enemy fire on.

Depending on the nature of the 'projectile' (i. e. is it being launched at relativistic, or near relativistic speeds), railguns / coilguns could potentially be very useful space weapons -- on the same order as energy weapons.  However, the ability to generate a miss (evade a shot) would make them primarily a short-ranged weapons system (relatilivly speaking!) -- any ship with any sense is going to be jinking around as best it can, and at a range of light minutes it should be possible to do so.  Missiles, with their ability to adjust course, avoid diffusion (they don't have to be perfectly calibrated to avoid range based difraction from imperfect focus

Look, it is completely irrelevant what "tech" setting the game is in - there are very few reasons for putting any sort of defense on the ground if it could be put in space instead.

The foremost reason for doing it would be to repel a ground invasion: Active planet based defenses makes excellent sense when the assumption is that any enemy wants to take the planet mostly intact with an invasion force. It should be abundantly clear in Sins that this is not the case: eradicating the population is not a choice of last resort, it is the choice of first resort - you don't send in an invasion force in Sins, you destroy the population centers and keep up blasting the planet until every last vestige of organize civilian opposition has been destroyed, and you do this from as distant a point in space as you can get away with.

A second reason could be if a ground based installation would be considerably more powerful than a space based one despite having further to travel and the athmosphere to pass through before getting to its target. It is a heck of a lot of work for any science fiction writer to come up with a good enough excuse for this one, but it can be done. The typical approach is "a lot of missiles on the planet and really bad point defense on the part of the invader and the invader, for one reason or another, not vaporizing the launching spots immediately when noticed - probably because you caught him in really low orbit directly over the launchers". Sure, it could work, but it doesn't sound like a plan to count on saving you from any enemy who prefers to hit the planet from extreme range. Flight time is a bitch.

The only thing that makes general sense regardless of science fiction setting is to place defenses in space - shorter range to their targets (unless you have your defenses hugging the planet), less problems for line of sight weaponry (assuming that any of your weapons are line of sight for purposes of guidance), less issues with collateral damage when the attacker starts wiping them out and to have shelters/city forcefields/whatever on the planet - things that actually help your people to survive..... and Sins already has all that, because that's really all that makes sense when the goal of any attacker is to wipe out the organised population, not to conquer it.

Interestingly enough, it is entirely possible that the planets, asteroids &etc in Sins already have significant ground based defenses to ward off invasion (in the minds of the designers of the Sins universe), but none of us would know since we are only extended the option to nuke 'em till they glow, then polish the world to perfection with our main batteries.

Do you have justification for why they would be inefficient? Your reasonings do not equate and scientifically and logically dont make sense. The problems you give are irrelevant compared to the advantage.

What reasons make it better in space rather then in space and on the ground? Missile systems would have minimal difficulty and laser or particle beam batteries would not have much problems either. If your using realism then you are using double standards so you will have to get rid of many other things also to be consistent.

Realistically their is no reason not to have planetary defense systems. Missiles and laser batteries would do great against planetary bombardment craft. Missiles with enough thrust could reach their targets in minutes faster then they could maneuver out of the way. And if they did evade they would have to stop firing on the planet and flee. A laser or particle beam powerful enough would simply cut through the atmosphere definitely far enough to do damage. With enough reinforcment they could effectively keep up a continuous bombardment form the planet. Far in excess of the reserves form ships.

The next point echoes what was said above and thats planetary bombardment is not useful on a wide scale. Troop invasions are far better with supporting air and space supremecy. Capturing cities and infrastructure intact outweighs the possible losses. If this wasnt true why have all wars fought the forces tried to capture all cities and resources intact if at all possible. Total bombardment was a last resort desperate measure never the first option.

Traditional brute force beam weapons yes, all energy weapons no.  Most plasma weapons in fiction require a containment field for the plasma, so the atmosphere would only interact with the containment field.  Range would be reduced as the containment field would break down quicker, but the damage done by the plasma would stay around the same.  A stationary planetary plasma weapon would be able to have a stronger method of containment as there is plenty of room and power for it.

That depends on what type of war is going on.  In a war of extermination(like SINS is currently) then the civilians are going to die anyway if the planet is taken.  If surrender is permited then you are correct.

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Anything which has to climb it's way up out of the atmosphere is going to be at a disadvantage compared to the same system launched from space, and that's ignoring the fact that something that has to deal with atmosphere is probably going to be designed different (read less effectively) than something that only deals with space.

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The advantage the planet has is that is has more of the item in question and will probably be able to manufacture more if it runs out.  Considering a planetary defense installation will be heavily fortified physically and, if they have shield technology, mount a much heavier one than what a space based attacker could mount.  This gives the planet a chance to win by outlasting attackers, or to last long enough for reinforcements.

The main limitation on planetary defense systems is technology, with relatively low levels then all the problems pointed out are true.  At technology gets much more advanced, then problems begin to go away.