As described in the previous section, Communication Schema, our signal has been designed to go through several stages of modulation, coding, chipping, mixed and diplexed, and amplified with several stages of power amplifiers. A block diagram showing the Moon to Moon Satellite modulation and RF chain can be found below. Note the high required LO to modulate this signal up to its place in the spectrum. The reasoning behind this is that we must transmit around 60 GHz of bandwidth but cannot begin transmitting until after 15.4 GHz according to spectrul regulations [6].
Link Budget Analysis from Moon to Moon Satellite
In order to create a repeater on the Moon Satellite, it is necessary to have a decent signal to noise ratio, neglecting all processing gain because the repeater does no processing [7]. It blindly repeats. If the noise-like signal is not above the noise floor, it will not be repeated and thus lost. The distance from the moon to the satellite is the radius of geosynchronous lunar orbit, or 88,450 km. We also assume the worst case propagation loss in using the wavelength for the highest frequency in our band. Because the Moon Satellite is in geosynchronous orbit about the moon, we use highly directional antennas with a 3dB beamwidth of 1 degree for the transmitter and 0.5 degree for the receiver, which can do tracking if necessary. By transmitting 1000 W, which is certainly not difficult for a terrestrial station exposed to as much sunlight as the Earth, a raw SNR of about 13 dB is achieved at the repeater. This seems sufficient. The calculations follow.
