Here is my 100% Guide for Deliver Us The Moon!
This is obtained in chapter 2 (Pearson Spacestation)
You will gain entry into a control room (After finding the code in Rolfs room in the sleeping quarters)
on the console directly infront of you to unlock a door.
From here, if you look up, you can see a computer chair floating on the ceiling.
What we have to do is basically push this chair straight through the new unlocked door, in here, unlock the airvent by using the laser on the monitor.
Once that is done, push the Blue button to unlock the door again, and from here, just push the chair out again and achievement will unlock.
The only tricky part is because your in gravitational floaty mode, it can be annoying sometimes to simply push it out.
Go to 36:00 in my video to see where and how this unlocks.
Hope This Helps!