Meteoria: Home of the Turrets

You are going to Meteoria, a small cluster of meteors guarded by automated turrets and sentries. Your mission is to find the control center and disarm the turrets with an access code. To do this, you need to find a portal that will transport you between three meteors. On each of those meteors, there is a white X you must find that gives you clues to the code. Once you have the complete code, you need to get to the heavily guarded, red-beacon meteor that houses the control center.

Find the portal on the first meteor. There is also a white X on the first meteor that has the first clue to the access code.
There are three white X's you need to find in total. They are only on meteors that you can teleport to.
Once you have the complete code, find the control center on the meteor marked with a red beacon and enter the code.