For this project, an Engineering Model (EM) of the Interstage GSSB was developed. This design replicates all the functions of the Gomspace Interstage GSSB. Since our team only ordered a limited number of Flight Models (FM), an EM was necessary for testing purposes, as additional FM units were too costly. To facilitate rapid development, I designed the EM to be Arduino-compatible and implemented all protocols to match those of the Gomspace FM. Since this panel does not need to operate in space, it is ideal for flight software testing.