What is "presat"

The PharmaSat Risk Evaluation (PRESat) CubeSat nanosatellite was about the size of a loaf of bread, weighed about 10 pounds and was constructed in just six months. PRESat contained a micro-laboratory with a controlled environment packed with sensors and optical systems that could have detected the growth, density and health of yeast cells in orbit.

The satellite was lost in the failure of the third Falcon 1 launch.