Grenade Launcher, which faction?

Which faction should I raid, to get the grenade launcher?

Phoenix, I think it’s came from main mission, forgot which one.

Raid Research* an Arthron’s body and you’ll get it.

Thanks for the list, but I can`t see out of the list, what is necessary to get the grenade launcher.

Is there a tech tree?

Is an Arthron the only thing necessary?

Arthron autopsy research item is all. Should be available to research after your first encounter with Pandorans.

No problem, please have a look from @Rainer and @Vipre said in the post. It will get you the grenade launcher. Have fun!