CubeSat telescopes exist as functional space payloads, and the literature confirms they require compact optical designs along with precise attitude determination and control systems.
The claim states that CubeSat telescopes exist and require compact optics and precise attitude control systems. Papers [2], [5], [6], and [9] directly support aspects of this claim by describing CubeSat-scale optical telescopes, compact instrument accommodations, and attitude sensors or mechanical stability analyses suited for nanosatellites. There are no papers contradicting the claim.