Hmmm, is the "computer's memory" (for data delivery) in any way dependent on the cargo capacity of the ship?
As I can only accept some 25 missions or so (but this way is indeed wonderful imperial rank grinding, thanks!)
No but data storage for missions is the same storage that all the stuff picked up whilst scanning targets is put and is only 500 items, so if you haven't traded it to engineers for upgrades or dumped it you can find yourself with no data storage quite quickly.