The Diomedes-class Combat Supply Ship is a specialised supply ship intended to accompany battlegroups on missions. The Combat Supply ship carries all the necessary materials to supply a number of ships simultaneously, such as water, hydrogen, reactor fuel, jet fuel, food and munitions. It can carry many thousands of tons of these materials, and millions of gallons of liquid material, in a number of self sealing tanks. The ship carries these in centrally aligned cavernous bays, which are connected to numerous docking bays and launch bays and are connected by an internal conveyor system. The ship is designed in such a way that it can rearm, refuel and re-equip four ships simultaneously, by docking with two and transporting supplies to the others via shuttles, allowing it to resupply them in just an hour. The ship itself is armed with a number of point defence guns, cannons and Archer pods, allowing it to defend itself against some threats, particularly light capital ships and fighter constellations.
The ship has decent armour and shielding, enough to defend itself against most similarly sized and armed ships, but is especially vulnerable when docked to other ships to resupply them. The Selene-class however is fast enough and well armed enough to keep up with battlegroups and defend itself while it preforms it's duties.