It would be great if schools could fly a CubeSat-sized payload for $21,000, or even less, but that isn’t going to happen until launch costs go down. Before someone says, “Elon Musk is going to do that” – no, he isn’t. At least, not in the near term. Nanoracks is already flying on the Dragon capsule and paying SpaceX prices. Further cost reductions are necessary.
The real answer, in the near term, is reusable suborbital spacecraft. The XCOR Lynx, for example, can easily accommodate a dozen CubeSat experiments with a payload operator. Without a payload operator, it could carry 100 or more. Based on XCOR’s initial retail price of $95,000 per flight, this means launch costs of a few hundred to a few thousand dollars per cube. Armadillo Aerospace, Masten Space Systems, and Virgin Galactic will be offering flights at similar price points.