User:Ejmusso25/Earth–Moon–Earth communication

Recent advances in digital signal processing have allowed EME contacts, admittedly with low data rate, to take place with powers in the order of 100 Watts and a single Yagi–Uda antenna. But in the article "Constructing Earth-Moon Data Relay System: Trajectory Design of Ballistic Lunar Transfer for Nano Spacecraft" it states, “However, communication with the Earth is difficult in the lunar south pole region, thus data relay by spacecraft is indispensable.”

Amateur frequency bands from 50 MHz to 47 GHz have been used successfully, but most EME communications are on the 2 meter, 70-centimeter, or 23-centimeter bands. Common modulation modes are continuous wave with Morse code, digital (JT65) and when the link budgets allow, voice. Another way that communications have improved is explained: “Free-space optical (FSO) communications offer a compact, light, and low-power alternative with higher data throughput and fewer limitations.” This was explained in the article, "SelenIRIS: a Moon-Earth Optical Communication Terminal for CubeSats,"