The mortars have a limited projectile tracking as if you watch they will curve towards the enemies or it could be the launcher itself but I don't see any movement from it though.
You gain a miniscule amount of XP for each tech killed (not sure how much, maybe 10 XP or so maybe, but its not a lot I know that at least) and decent chunks on the xp bar (300 or so most of the time) if you do missions (defeat ambushers/we've got hostiles/harvest X resource/tech and invader hunting). The mission log will tell you how much per mission completion IF in the unstable version as the mission log (along with the missile range doubling)was updated with the 0.7.1.1 or 0.7.1.2 unstable update. I believe 0.7.2.0 stable (with the mission log update) will be released before they take the rest of the year off (just what I recall hearing during one of the recent streams IIRC and the new end of year contest info @Jamie posted today, the taking off rest of the year that is).
I've found that (at least in the past versions) if I can grab it before it explodes I would unlock it. Alternatively, with the new crafting you can craft any unknown blocks, at your current grade rank that is.
Also I find having a large scrap magnet or two helps with that if you have repair bubbles around the magnets holding area. Doesn't always work however especially when certain techs/corporations like to explode (looking at your Venture), but my success rate has been pretty high, even got all the crashed Hawkeye planes parts (minus the cab) from the first mission (Bird Of Prey), the ones that are supposed to explode when you get near.
It's also cool looking to see techs explode when I'm near and the parts sort of boomer-rang back to my magnets. Or when i'm chasing down the runners and the parts flying to my magnets as I blast their back-sides (or front-sides if they like to watch).