Cubesats are basically the size of a milk carton, an inteface standard produced by CalPoly for four standard sizes of satellite, 0.5U, 1U, 2U, and 3U. Each U is a kg and a L. The height and width are always 10cm, each U is 10cm of length. This standard is based on how the deployer pods work (there are more than the well known P-POD in service.) The satellite rides out of the deployer pod on corner rails; it is fired out by a spring pusher, very similar to the way a Nerf (tm) gun works. The 3kg payload of the deployer pod is the basis for Prochron's payload objective.