Small satellites and payloads in the (1-2 kg) class called Cubesats and (20-30 kg) called Nanosats have been under development at the University of Illinois since fall, 2001. The ION1 Cubesat was a 10×10×21.5 cm 3 satellite with the experiment consisting of photometric remote sensing of mesospheric structures (near 94 km) in the O 2 (0,0) band airglow at 762 nm. ION1 development began in 2001 and was lost on the failed launch attempt, July 26, 2006. ION2 development began in Fall 2005, and has a remote sensing experiment to measure Ha (656.3 nm) originating in the Earth's geocorona from which column H densities can be deduced. Taylor University has led the development of a Nanosat called TEST, which was designed to study ionospheric structures. Illinois provided remote sensing payloads including a CCD camera and dual photometers. The development activity is largely implemented by a College of Engineering Interdisciplinary Design class (ENG 491), where students typically participate in the systems engineering experience for two semesters. The students (15-20 average enrollment) are responsible for the design, fabrication, and testing of the systems. This paper describes the development of these Cubesat and Nanosat systems.