Nature Communications Article Features LO-94, First Lunar-Orbiting Ham Radio Spacecraft A July 9 Nature Communications article, “Design and flight results of the VHF/UHF communication system of Longjiang lunar microsatellites,” describes the Longjiang-2/Lunar-OSCAR 94 (LO-94) spacecraft, which carried the first amateur radio communication system into lunar orbit.

As a part of China’s Chang’e-4 lunar far side mission, two lunar microsatellites for low-frequency radio astronomy, amateur radio, and education — Longjiang-1 and Longjiang-2, were launched as secondary payloads on May 20, 2018, along with the Queqiao L2 relay satellite. Five days later, Longjiang-2 successfully inserted itself into an elliptical lunar orbit of 357 × 13,704 kilometers (221 × 8,496 miles) to become the smallest spacecraft to enter lunar orbit with its own propulsion system. The satellite carried a VHF/UHF SDR, designed for operation with small ground stations.

The article describes and evaluates the design of the VHF/UHF radio and the modes used. Flight results of the VHF/UHF radio are also presented, including operation of the radio, performance analysis of downlink signals, and the first lunar orbit UHF very-long-baseline interferometry (VLBI) experiment.