Modification of Ground-Use Stepper Motors for Use on the Stratospheric Flight of EUSO_SPB2

Two custom telescopes aboard the Extreme Universe Space Observatory Super Pressure Balloon (EUSO_SPB2) will detect cosmic ray air-showers via Cherenkov and fluorescence light. During the flight, stepper motors will be used to open and close telescope pupil covers and to control the azimuth rotation of the telescopes.

At a planned flight altitude of 33 km, EUSO_SPB2 will not experience the zero vacuum or cryogenic temperatures experienced by deep-space missions. Relative deep-space instruments, there is a significant cost-saving opportunity in identifying stepper motors tailored to the conditions of EUSO_SPB2. My project is to test common ground-use stepper motors under conditions expected during the EUSO-SPB2 flight and engineer modifications to ensure performance.

I will select these motors based on historical low-orbit applications. A cold box that houses a motor testing stand capable of supporting a variety of motors has been constructed. The repetition and repeatability for the following with be acquired through testing: torque vs. speed, step count, holding torque, ambient temperature, and voltage waveforms as a function of load.