Missions can fail for several reasons... and it's fine.
For example if you have to steal something without being spotted, it's ok that the mission fails when someone scans you or you trigger an alarm.
But missions fail upon death and this is frustrating for the waste of time that it takes to go back in the action, it takes an average of 20 minutes to go back to the gameplay because you respawn in your ship, fly to a starport to get another mission and go back to the target location.
So it's not that the price to pay in the game is too high... it is the price to pay in the real life that is unfair.
This is not even logical for some type of missions, for example in a mission where I have to restore the power, why the mission should fail if I get killed in combat? I should just retry it. It's not that the outpost is automatically doomed.
So this is not a fair penalty because death in the game affects the time in my real life. Instead the penalty is something that should remain in the game only.
FDEV should introduce a mechanics upon death that affect the gameplay only. For example reduce the reward or the reputation with the faction everytime you get killed. So that when I die 3 times the reward goes to 0 cr and then the mission fails.
Then restore all the dead enemies of course (dropped again in a drop ship), you lose all materials collected and all mission progress is reset of course... Things don't need to be over complicated.
Im on the same boat, it's ok that there is some penalty, but should be in-par with the same missions in ship.
When you got a mission of "kill 30 pirates" and you die when having killed 15 you lose the creds for the kills not redeemed, but he mission still continues.
Also there are some missions with some "Bonus reward for avoid being killed", that maybe be good for FPS missions as it could have a base mission payment (maybe kinda low) and a great bonus for doing mission flawless, maybe the concept of "3 tries or failed" could be interesting as well.
Maybe guards not so GTA style that shoot when you don't stop for scanning could be good as well, also 3 warnings until guns come to play, something like "Stop for scan... Hey you seriosly I have to scan you.... FREEZEE NOW... (peim peim)". Think of this also on spaceships, I have been stopped for scan but never been shot so often as on foot, and I could escape them easily if it comes the situation, maybe ship scans should be a bit more dangerous too?
If title of thread can be change I suggest for OP change "remove mission failure upon death" for "REWORK mission failure upon death" or "upon certain circumstances"