Communication system and operation for lunar probes under lunar surface

In the Japanese LUNAR-A mission, penetrators will be deployed to the Moon for global seismic measurement. The unique communication system between the subsurface probes under the lunar surface and the lunar orbiter is described. Radiowave propagation through a crater which is formed at the penetration is investigated by means of scaled measurements in a simulating environment. Acquisition and tracking sequence is optimized within limited power capacity of the probe to maximize contact time between the probe and the spacecraft.