The RebelSat-1 team has completed PDR, showing that correct design options have been selected with all interfaces identified. Completion of PDR entails an established basis for proceeding with the final design. FlatSat is a flat configuration of the satellite used to test and verify our design. FlatSat will allow the RebelSat-1 team to verify our satellite's functionality in a controlled environment, and identify and fix any issues that may come up.