On Apollo missions all communication between the spacecraft and earth — the telemetry, tracking, automatic commands and voice circuits — are combined in a single radio carrier wave which involves the use of only one antenna. This is called the 'unified S-Band system' and involves a staff of 4,500 distributed among fifteen tracking stations and numerous switching centres around the globe.
While the spacecraft is in earth parking orbit and just before splashdown, communications are routed through thirty-foot dishes at eleven sites on land and aboard four tracking ships. In addition to these thirty-foot dishes, eight Apollo range instrumentation aircraft (ARIA) operate in the Atlantic, Pacific and Indian Oceans. These are modified Boeing jets which carry seven-foot antennae in their bulbous noses. Once the spacecraft has completed the translunar injection burn and is on its way out to the moon, three more powerful eighty-foot dishes — one at Goldstone in California, one near Madrid, and one at Honeysuckle Creek near Canberra — come into action. These deep-space tracking stations are so placed that, while the earth revolves on its daily axis, one of them can always 'see' the moon. On the Apollo 11 mission two even more enormous 'electronic ears', the 210-foot Mars antenna at Goldstone and the 210-foot dish at Parkes in Australia, were used. The Mars antenna was brought in to assist communications with the lunar module once it had separated from the command module in lunar orbit, while the Parkes dish was used to receive the television transmissions from the surface of the moon.
Apart from handling the voice, telemetry and command circuits between the spacecraft and earth, the dishes are also used to track the craft in space. By measuring the round-trip time of a ranging signal, automatically re-transmitted by the spacecraft and measuring the Doppler shift (the re-transmitted signal's frequency change, like the change in note of the whistle of a passing railway train), it is possible to determine the range of the craft to within a few hundred feet and its range rate or speed to within a few inches per second.
Linking all the tracking dishes of the MSFN is NASA's staggering global communications network (NASCOM). Using a web of about two million miles of cable, microwave, radio and satellites link, it is centred at the Goddard Spaceflight Center (GSFC) in Maryland. Information originating from the Apollo 11 spacecraft ('down-link data') such as the heart and breathing rates of the astronauts, the command module cabin pressure and temperature, etc., was transmitted automatically, second by second ('real-time' telemetry), through the cluster of four small S-Band dishes deployed outside the service module at the rate of 51,200 bits per second. Picked up by a ground station, it was then processed by computer before being passed on to Houston at a modest 2,400 bits per second. These computers at the tracking sites are also used for relaying commands to the spacecraft's systems for passing information ('up-link data') to the spacecraft's own computers at the rate of 1,200 bits per second. Several times a second the computers at Houston 'talk' to the other computers in the network or in the spacecraft. The MCC computers compare everything they receive from other computers with their memories and then indicate problem areas and other relevant data to the flight controllers. Another important function of the Houston computers is time-keeping, and they deal in thousandths of rather than whole numbers of seconds. Between Houston and the centre of the NASCOM web at the Goddard Spaceflight Center there are two 50,000-bit-per-second circuits. The volume of traffic handled at Goddard during an Apollo mission is equivalent to a 500-page novel per second. The computers there would take less than a second to add a column of ten-digit numbers three-quarters of a mile high. To talk to their operators, the computers around the network are capable of slowing down to a more reasonable 100 human language words per minute.
How about when the module landed there seemed to be no dust on the module after it landed. 
I hope I can still be cool though. LOL
