Defending Planets

The only real defense for your planets is your own fleet.

Mines can be a useful defense in the early game, and specialist warp-point defenses can help (satelites, bases, ship-capture and ram-ships). But in the end mobility (both strategic and tactical) is key.

All you can do, is keep the other guy honest. Make sure that you have enough mines and weapons platforms (or whatever) so that taking or glassing each planet requires a serious effort. What you'll never want to see is a handful of ships raiding "behind the lines" and blowing up loads of planets before you catch them.

Mark

[Suicide Junkie]

"But in the end mobility (both strategic and tactical) is key."

Where would you draw the line in a QNP game?
You can have an unarmed destroyer with 20 MP, a slow, heavily armed gunboat destroyer, or anything in between.

[PvK]

One good place to draw the line is slightly above your opponent's speed. Being faster than the opponent gives a major advantage - being as fast as possible gives diminishing returns, especially because you cut other abilities to get that mobility. Also, if the line is set quite high, it may be worth cutting to a slower speed to gain ability. In QNP, especially for larger ships which take a lot to move, slow and strong ships are more appealing. For defensive ships too, they can be slower.

In Proportions, it may well be possible to build up a planet that is not worth attacking, in terms of the fleet casualties. One major cause of this is the very high capacities of non-domed colonies.

Even in the unmodded game, though (at least in Gold with drones and platform mounts), it is possible to build very powerful defensive planets that can stop an invasion fleet. But it's only possible to build a few such planets, and it comes at a large price which might be better spent elsewhere. On the other hand, being unpredictable is a major advantage in itself, and players usually don't expect to lose a large fleet to a planet.

PvK

I've never played a QNP (or any other modded game) with other humans, so I don't know about this. But the kind of speed arms race that PvK implies might happen sounds amusing.

He goes to speed 7, I up it to 8, he goes to 9... Where do we stop?

But I suppose that was the original question.