Stationkeeping strategies for close formation flight on distant retrograde orbits

Distant Retrograde Orbit（DRO）is a family of large-scale，lunar-retrograde periodic orbits in the cislunar space. Due to its advantages of long-term stability and low-energy transfer，DRO has become a potential orbit for many cislunar space missions. Investigating close formation techniques on DRO is of great significance for cislunar on-orbit servicing. Considering navigation and execution errors，it is essential to study the uncertainty propagation of close relative motion on DRO and design stationkeeping strategies. The fundamental solution set of linearized relative motion on DRO obtained through the Floquet theory is introduced. Based on periodic solutions，analyses of sensitivity and safety uncertainty propagation of DRO formation flight are conducted using the Cauchy-Green tensor and unscented transformation，respectively. Based on these analyses and considering engineering constraints，it is found that keeping the maneuver frequency of 2 times per cycle and the maneuver locations at two perilunes is the near-optimal stationkeeping scheme. Following this，two stationkeeping algorithms are proposed based on the concepts of relative trajectory following and absolute phase bias. The simulation results show that both stationkeeping algorithms can ensure long-term safety and reasonable configuration of DRO close formation flight. © 2024 Chinese Society of Astronautics. All rights reserved.