Yeah, Carmack has a rocket company: http://www.armadilloaerospace.com/

And it looks like he used some tech from Armadillo in this unit. The software for the gyro sensors come straight out of the Armadillo rocket tech. Awesome. (see the youtube video mentioned in another comment)

Well, the software. IIRC, the Armadillo flight electronics use a Crossbow IMU, (which must be very accurate, endure a whole lot of vibration, and drift very little) which is $100k.

Or the fact that Carmack has driven a lot of innovation in 3d hardware for that matter. (Tim Sweeney likewise.)