can you not respawn when you die

Hello, yes.

When you die, you can't respawn and mission is failed. It is recommended to set autosave (3 or 5 minutes at least). :-)

This mechanic is done because of the scripts and progress in the campaign.

that sucks how do i beet the lasers level thin that do so mush damige

Laser level? You mean level 5 when you trying to save the lasers?
You actually can't save them all.

Or if you mean that enemy lasers do much damage to you, just make some better armour (modular with shield) or hide to the vehicle or bombard them from distance by rocket launcher.

Also you can alsways reduce the difficulty or you can watch lets'play videos on YT of each mission.

ok