Gravity Crash

There are some 55 crewman stranded across various planets. Not every planet has crewmen on it. They will be little green dudes walking around on a level surface, waving at you. To rescue them you need to land nearby and they will enter your ship. To land, slowly lower your ship to the level surface, nose facing up. If you do it right the landing gears on your ship will extend. Be careful not to tilt too much or you will crash and explode.

You can kill the crewmen and miss them completely, but they can be found in Planet Mode as well. Like other collectibles, however, I recommend you do them during your Campaign run.