I was thinking of creating a few planets full of storage items(mineral storage tower, artifact warehouse, and research data archive) so in case I couldnt sign on for a while I wouldnt lose out on too much production. The problem is if I were to buy all that gp and someone manages to swipe those planets then I'm out a bunch of real $.

What I propose is this... Like the mission planets (which 99% of the time also require gp) planets with storage items should be made invulnerable. In order to balance this no production structures should function on a planet with a storage items.

Sorry, have to say no.

Either take the risk, and build them on a non-immune planet, then max out defences/cloak, or take a big hit in your production and build them on a mission dyson/exotic/rift.

I recommend putting them on a Very Large Volcanic, so you can max out the passive attack and then use a Thermionic Intensifier, that's probably the best thing to do.

Find a very massive gas planet(69 space) and place 5 of each item on the planet taking up 30 space. That leaves you with 39 space left, using that place 19 defense structures(+750 defense or +1200).

That along with legion bonus will make your planet pretty much untakeable unless a legion happens to have access to plenty of cluster missiles to waste or a load of sabs.

I've got a planet on scan that has done the above and theres no way anyone could take the planet, bar bringing in 24 sabs.

I have done the same kirk, though some bonus would be okay, maybe 200 defense passive per structure?

I like this idea , but not invulnerable It would be to easy to put 1 on every good planet to keep it safe.

How about just the building unstealable, ie when invaided the building "blows up" that makes no incentive to steal them while mainintaining there current in game effect.

no to making them invulnerable otherwise all of my good planets id place one on and make them invlnerable

This is why production structures wouldnt function if there was a storage artifact present. If you put one on all your good planets your production would drop to nothing.

oh i didnt see that part i think though it should have say 300 passive defense attack and cloak

The other problem is this:
Planet is under attack.
You put one of these on it, making it invincible.
You flux the planet.
You then use a build extractor to take it off, restoring the production.
EASY defence for anyone, making CC users planets VERY hard to take, unless the person's offline.