I'm sure I've made this suggestion before, but cannot find evidence of it:
Please change the "Refuel at Refuelling Hub" and "Refuel from Colony or Hub" conditional orders to function for Refuelling Systems (i.e., traditional tankers). This would make managing survey fleets significantly easier as the option to station a tanker is easier and more robust than the requirement to mount a 10,000 RP + 100,000-ton component or establish a refueling station on a planet. Frankly, since the purpose of the Refuelling Hub is to refuel many ships at once, and the most common use of the refueling conditional orders is for single survey ships, I see no reason why a Hub should be required for access to a conditional order anyways.