In-Flight Performance of Psyche’s Integrated Solar Power and Electric Propulsion Systems

This paper describes the in-flight performance, testing, and integrated operation of the Psyche spacecraft’s solar power and electric propulsion systems during interplanetary flight. Over the first 18 months of flight, flight data confirm that the power system is operating nominally, delivering a stable, fully regulated high-power bus to drive the electric propulsion system across a broad range of mission conditions. The solar arrays are generating slightly more power than prelaunch predictions, and the combined electric propulsion and power systems have demonstrated the capability to support both cruise and orbital operations at the target asteroid, named “(16) Psyche,” through the full mission duration. Flight data highlight the critical role of solar array temperature predictions in determining array voltage and power output. Higher-than-expected array voltage, coupled with evolving spacecraft loads, has led to transient interactions between the power and propulsion systems—some of which have affected the Magnetometry Investigation. These effects are nondisruptive and do not compromise the mission’s science objectives. Overall, the spacecraft continues to perform well as it heads toward its asteroid rendezvous in 2029.