Sitting ducks: Destroy all cargo ships in the base
To obtain this before completing the planet, you need the Visibomb Gun: At the place where there is green acid rising up and down, you can see a gold bolt behind a force field if you look from the highest platform that the acid cannot reach. If you have done this area before, the force field won't be there anymore. However, if you have not, there is a way to destroy the field: from your ship, shoot the Visibomb, and keep the visibomb going straight until you see a big large building with a wide opening in its dome-like top. Go through the opening with the bomb, and then go down, following the curve of the wall. You will crash into a force field generator tower which will deactivate the field blocking the gold bolt. It is now obtainable. Note: If you are already next to force shield, then there is no need to go back to ship. There's a window in the acid room. Shoot a Visibomb rocket to that window and go a little far from the station. In an upper level from the place you just shot, there's a tower. Go around it until you've found the curving entrance. Enter it and destroy the force field generator to open the wage until bolt.