Event Title

ExoCube and a Gravity Gradient ADCS

Presenter Information

Jeff Weaver, Cal Poly, SLO - PolySat

Session

Pre-Conference: CubeSat Developers' Workshop

SSC13-WK-20.pdf (2134 kB)
Presentation Slides

Abstract

Exocube is a 3U research satellite with a mission to measure various ions and neutrals in the Exosphere. The project is funded by NSF and uses two instruments built by NASA Goddard Space Flight Center. To obtain accurate data, the satellite must maintain very low angular rates and a Nadir pointing less than +/- 10 degrees. Cal Poly designed an attitude determination control system (ADCS) to maintain this pointing requirement throughout the mission. The ADCS is a gravity gradient system with a Kalman Filter, PD controller, and Sinclair momentum wheel. Through simulation, it has been proven that the system will maintain pointing and stability throughout the mission. A camera is integrated on the satellite to provide external verification of the ADCS through derivative imaging of the Earth. Currently, the ADCS is being integrated into hardware for further testing and verification. To further enhance the system, a damper is being designed to be added to the satellite. The goal of this damper is to maintain pointing with the ADCS turned off after stability is reached. This allows all power to be dedicated to the instruments, communications, and the momentum wheel.

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Aug 10th, 10:00 AM

ExoCube and a Gravity Gradient ADCS

Exocube is a 3U research satellite with a mission to measure various ions and neutrals in the Exosphere. The project is funded by NSF and uses two instruments built by NASA Goddard Space Flight Center. To obtain accurate data, the satellite must maintain very low angular rates and a Nadir pointing less than +/- 10 degrees. Cal Poly designed an attitude determination control system (ADCS) to maintain this pointing requirement throughout the mission. The ADCS is a gravity gradient system with a Kalman Filter, PD controller, and Sinclair momentum wheel. Through simulation, it has been proven that the system will maintain pointing and stability throughout the mission. A camera is integrated on the satellite to provide external verification of the ADCS through derivative imaging of the Earth. Currently, the ADCS is being integrated into hardware for further testing and verification. To further enhance the system, a damper is being designed to be added to the satellite. The goal of this damper is to maintain pointing with the ADCS turned off after stability is reached. This allows all power to be dedicated to the instruments, communications, and the momentum wheel.