Session
Technical Session VIII: Frank J. Redd Student Scholarship Competition
Abstract
At altitudes below 500km, satellites experience a significant amount of aerodynamic drag that can be utilized to stabilize satellites to align with the relative wind direction. Designing a spacecraft such that the center of pressure is behind the center of mass provides an aerodynamic restoring torque, that in combination with an oscillation damping system, provides stability and alignment with the spacecraft velocity vector. Passive aerodynamic stability and damping has been demonstrated on orbit by the Soviet Union on Cosmos-149 and Cosmos-320 and by NASA on the PAMS spacecraft which was deployed from STS-77. This paper discusses aerodynamic stability solutions for the CubeSat domain, where CubeSat form factors are significantly smaller and lighter than the previous flight demonstrations and they must fit inside a CubeSat launcher and only deploy aerodynamic elements post orbit-insertion. Completely passive solutions for 3U and 1U CubeSats are described where aerodynamic fins are deployed and magnetic hysteresis material is used for oscillation damping. Greater velocity vector alignment can be achieved using active rate damping, utilizing a magnetometer and magnetic torque coils running the B-dot control law to provide improved oscillation damping. Component selections are offered to create off-the-shelf aerodynamically stable CubeSat platforms. Aerodynamic stability is suitable for the altitude and inclination of upcoming CubeSat flight opportunities on ISS crew resupply missions.
CubeSat Aerodynamic Stability at ISS Altitude and Inclination
At altitudes below 500km, satellites experience a significant amount of aerodynamic drag that can be utilized to stabilize satellites to align with the relative wind direction. Designing a spacecraft such that the center of pressure is behind the center of mass provides an aerodynamic restoring torque, that in combination with an oscillation damping system, provides stability and alignment with the spacecraft velocity vector. Passive aerodynamic stability and damping has been demonstrated on orbit by the Soviet Union on Cosmos-149 and Cosmos-320 and by NASA on the PAMS spacecraft which was deployed from STS-77. This paper discusses aerodynamic stability solutions for the CubeSat domain, where CubeSat form factors are significantly smaller and lighter than the previous flight demonstrations and they must fit inside a CubeSat launcher and only deploy aerodynamic elements post orbit-insertion. Completely passive solutions for 3U and 1U CubeSats are described where aerodynamic fins are deployed and magnetic hysteresis material is used for oscillation damping. Greater velocity vector alignment can be achieved using active rate damping, utilizing a magnetometer and magnetic torque coils running the B-dot control law to provide improved oscillation damping. Component selections are offered to create off-the-shelf aerodynamically stable CubeSat platforms. Aerodynamic stability is suitable for the altitude and inclination of upcoming CubeSat flight opportunities on ISS crew resupply missions.
