Using laser altimeter as a backup measuring device during spacecraft rendezvous in lunar orbit

The paper proposes using laser altimeter as a backup measuring device during manual control of spacecraft rendezvous in lunar orbit. It presents engineering specifications of laser and radar devices used for taking measurements during controlled descent onto the planetary surface, and during spacecraft rendezvous. An analysis was conducted of the requirements for laser altimeters as measuring devices in support of spacecraft rendezvous. Energy-based calculations of the measuring range were performed, taking into account the characteristics of the passive spacecraft and laser safety requirements. The paper discusses the methods of protecting the photodetector against saturation with the reflected signal. A relationship was identified between the level of attenuation provided an optical attenuator and the measuring distance, which protects the photodetector in close proximity to a diffusely reflecting passive spacecraft and a retroreflector. The obtained results demonstrate the feasibility of using a laser altimeter for manual control of spacecraft rendezvous in lunar orbit.