I agree with the comments about having to smuggle mines to unlock an engineer, that one could easily cost an inexperienced smuggler and even get him killed.
The painite one is a bit off too as there are only two ways to get it, either take up mining or make friends with a miner or 2. It is easy enough to make friends in the game and find a miner that is willing to help you out.
The 25 unknown fragments is also uncool for several reasons.
Any of the minerals that are never offered as mission rewards are a bit off as there are then again only 2 ways to get them, either take up asteroid mining or surface mining...
The mining aspect is not for every one, for me it was ok at first, but to be honest it really makes me want to go to bed and sleep, instead of falling asleep in front of the computer, so I do get that its not for everyone.
The surface mining I don't really have a huge problem with because I tend to take missions that put me on planets and then while I'm there in the srv I make it worth my while by looking in meteorites and looking for shipwrecks, this usually gives me all the materials and minerals I need as well as all the software I need. I am actually constantly throwing tons of both away because my mini cargo is always full....
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As for the few materials besides painite which I mentioned separately only because I have never yet seen it as a mission reward, these can all be gotten as mission rewards.
Osmium, Samarium, Praseodymium, Platinum are all given as mission rewards.
I have mentioned this in a few other threads on this same topic and I really don't get why it seems to be either ignored or dismissed.
It is actually a very simple method of generating credits to go to a starport that actually sells cobalt, indium, and a few others and take the mining missions for cobalt, buy it from them in their market, turn the cobalt in and get 4 platinum or 4 Osmium,...etc....Seriously, I have not only done upgrades this way but prior to the engineers I have made millions using this method without having to leave the station. It was the very first fast cash method that I learned in the game when I started, the only difference is that the first station I visited was offering big cash for slaves and they actually sold slaves at that station. So I easily became a millionaire my very first week in the game without having to leave the station.
There are several materials that can be traded this way without leaving a station, but this was mostly about items that people think require mining and you don't have to mine for anything except for unlocking 1 engineer and a fast way to do that if you really didn't want to mine in the first place is outfit a ship for mining and simply process everything you come across and keep emptying your cargo till you have met the required quota, takes about 2 hours to do that. Then sell your mining stuff back to a station and off you go...done.
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I like to think that every player is looking at the mission boards no matter what their in-game role is, if not they are missing out on a lot and in many cases are working harder than they need to in order to generate the much needed credits that we all need simply to upgrade anything or even for refueling and re-arming.
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One of the main points of this game is to explore (kinda part of the reason its a very large space game...) and it is a multiplayer game, so make some friends too. Doing both of these things leads to everything else that the game has to offer.
And the worst thing you can do to yourself is to expect or to even try and get everything at once as fast as possible.
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All this and I still get everything I need for mods and zero killing except in my case some of the missions I take are for killing skimmers aka flying robots....and they happen to always be 'Wanted' anyway guarding a crash site so now I get paid for killing them and I get the cargo and any other mat's laying around.