So I finally saw Avatar....

[Khuutra]

Kasz216 said:

Khuutra said:

The ships were manufactured on site except for the big one! And they didn't have facilities to produce the chemicals necessary for making weapons!

And actually, it's pretty clar by the end that mining the unobtainium is no longer cost-effective.

And no, it's not a safe assumptin at all - how much do you think one of those missiles weighs? As a guess.

Wait wait wait...

they named it Unobtanium?  That's just silly... and a giant spoiler for pretty much anybody with any common sense. 

Actually it's a pretty common element in science fiction and thought experiments:

http://en.wikipedia.org/wiki/Unobtainium

They also did bring a standing army and enough guns and explosives to utterly wipe out the body of the Na'vi in the area where they lived. They were prepared to kill them if things went bad! That is what happens. It's what that awesome final 45 minutes of explosions and wild animals was based on.

And making a chemical weapon for an alien biology is probably harder than you would think - like I said, it's only the second trip to Pandora, and they may not be affected by terrestrial viruses at all. And don't they breathe cyanide?