As soon as you fly over them, they die and you won't lose any health. Each one deals 1 damage. The further you fly away from your spaceship, so faster they will disapear. Try to upgrade your speed? Hope this helps! :)
Hmm odd cause I had groups of 3 just instant teleport me back from full 6 health and those are hyst cause asteroids got in the way so I wasn't able to get to them
