A possible extension would be to allow simple or complex command queuing.
An example of a simple command queue:
1. Build a ship
2. Relocate the ship
(this could also be achieved by give a "build target" for a colony, all ships built here would immediately go to another colony
This would more easily allow users to consolidate / reinforce their fleets.
Example of complex command queue.
1. Attempt to colonize planet.
2. Build orders upon colonization.
This type of queuing is a little more complex, and may not be desirable.
P.S. Good game, keep up the good work.