Naoya Ozaki

Flyby navigation and guidance experiment for interplanetary micro-spacecraft PROCYON

This paper presents the planning, flight results and lessons learned of flyby guidance experiments of interplanetary micro-spacecraft PROCYON. PROCYON is the worlds first interplanetary micro-spacecraft and was launched on 3rd December, 2014. Orbital control of interplanetary micro-spacecraft is challenging because of severe restriction and lower reliability on spacecraft system. For guidance strategy of PROCYON, we have introduced an innovative guidance strategy by two-stage stochastic programming for thrust-direction-constrained problem. Although the flight experiment has many difficulties especially on navigation, the flight result shows that we successfully demonstrate that PROCYON has been guided to the target point with objective guidance accuracy, which is within 100[km] on B-plane at 3,000,000[km] distance from the Earth. These results contributes the future flyby navigation and guidance for interplanetary micro-spacecraft, which has severe constraints and lower reliability on spacecraft system.

Stochastic Differential Dynamic Programming with Unscented Transform for Low-Thrust Trajectory Design

Low-thrust propulsion is a key technology for space exploration, and much work in astrodynamics has focused on the mathematical modeling and the optimization of low-thrust trajectories. Typically, ...

Low-Thrust Trajectory Optimization Method Considering Stochastic Operational Anomaly

This study aims to optimize a low-thrust trajectory for spacecraft in the event of stochastic operational anomaly. Most of the recent study have focused on the deterministic trajectory optimization for preliminary mission design. In the low-thrust operation, which conventionally use empirical (nonoptimum) operation strategies, the duty cycle of low-thrust propulsion is imposed throughout the trajectory. This paper presents the optimum value of duty cycle in the each operation cycle using Lagrange multiplier. The result shows that constant duty cycle constraint is optimal solution if surplus coasting period in the unit operation cycle is not used as thrusting period; in other words, the constant duty cycle throughout the thrust arc is not always optimum strategy if surplus coasting period is intensively used at the end of thrusting arc. Numerical example shows that the solution calculated numerically corresponds to the theoretical solution.