Cycler Trajectory

Author: CislunarSpace

Website: https://cislunarspace.cn

Definition

A cycler trajectory is a natural periodic orbit that connects two celestial bodies, considered a special type of resonance orbit. Cycler trajectories enable continuous round-trip travel between the two bodies but cannot maintain orbit around either one. The concept was first proposed by Aldrin in 1985 for Earth-Moon cycler architectures.

The cycler architecture includes two key components: a transfer vehicle that uses the cycler orbit for round trips between the two bodies, and a transport vehicle that shuttles crew and cargo between the cycler and each body. Since the transfer vehicle does not need to be captured into orbit at either destination and can be reused indefinitely, significant propellant savings result compared to conventional direct transfer approaches.

Key Properties

  • Periodicity: The orbit repeats indefinitely, passing by both celestial bodies at regular intervals
  • No capture required: The transfer vehicle never enters orbit around either body, eliminating costly orbital insertion burns
  • Reusable infrastructure: The large habitat and propulsion modules remain on the cycler permanently
  • Resonance condition: The orbital period maintains a rational ratio with the synodic period of the two bodies

References

  • Aldrin, B. (1985). "Cyclic Trajectory Concepts." SAIC Presentation, for the Lunar Science Institute.