It's one time use I'm afraid, I believe you transfer 1 ton of fuel with each drone. Again, I recommend that you focus on limpets, and not extra fuel.
Also, relocating the video-documentation of EXERCISE Fuel Rat due to youtube being silly. Please stand by.
Awesome video
Important question - does the cargo hatch definitely need to be opened? I have had different answers from people in the Beta and it makes a big difference to if you can be rescued or not. With absolutely no fuel you can't open the hatch...