COMMUNICATIONS

[Music] [Music] Uh flight cap. Go ahead. Completed the post check down to whatever the CMP has to get out of a couch. Standing by for your go no go. Roger. The windows appear to be almost crystal clear which is good news for all of us. Roger. Okay. Stand by. We may want to get you a nav load right now for the go. No go. Standby. GNC. Everything okay? Go flight. Looks good. Flight. Tell me about the cabin. Cabin's 56. Looks good. Just coming on down in the regulator band, right? That's a firm flight. Okay. Uh Capcom flight. We're giving a go. Guidance wants to give an update. Okay. When three astronauts begin their journey to the moon, nearly 240,000 miles away. Their only link with the Earth to ensure their mission's success and safe return is the communication system. from thousands of pieces of information on spacecraft performance, on flight path, and on astronaut heartbeat. From a steady stream of coded signals flowing into the giant computer complex, successive teams of flight controllers, systems experts, and medical specialists make decisions around the clock. and relay them to the astronauts right now. Looks like we're getting it. And their only link is the communication system. 3 2 1 zero [Music] cut off. Man, that's a ride and a half down there, guys. Roger. Copy that. In an Apollo mission, nearly continuous radar tracking, command signals, telemetry reception, and voice contact are provided by a worldwide network of tracking stations. They are electronically linked through a communication center at Gddard Space Flight Center in Maryland with the command and control point for all phases of Apollo flights, the mission control center in Houston. Burning out the residuals. Roger. Copy that. Standing by. Roger. through Hawaii. Hawaii did anything else. The tracking network consists of ground stations, ships, and aircraft with special instruments on board. New in Apollo missions, these aircraft provide additional links between the spacecraft and the mission control center. Otherwise, more fixed ground stations and ships would be needed. 8 7 6 5 4 3 2 1. Once the spacecraft is 12,000 mi from the Earth or about 120th of the way to the moon, communication is augmented further by three deep space stations. Goldstone in California, Madrid in Spain, and Cannber in Australia. Affirmative. Flight pattern. Looks like a perfect 10.3. Equipped with huge 85 ft dual antennas. These stations are located 120° apart longitudinally. As the Earth rotates, one of them will always be in line of sight communication with the spacecraft. Line of sight communications are provided in many ways. When radio signals from the spacecraft are received and evaluated by ground stations, the spacecraft's position and its rate of travel can be determined. Let me know what your track says. Other telemetry signals provide complete information on how well the spacecraft is operating and if mission events are occurring as planned. Capcom, go ahead. Houston Capcom voice check. How are you reading? Good morning, Jack. Two-way voice communication is available nearly 100% of the mission, even during astronauts extra vehicular activities and provides the crew with added capability to compare and evaluate data with computations from the ground. The ground stations also receive radio telemetry to continually monitor the crew's physical condition, whether they are inside the spacecraft or outside walking on the lunar surface. Telemetry data on each astronaut's heartbeat, blood pressure, and body temperature are transmitted to the Earth from the space suit communication package through the spacecraft. TV turned on. Stand. We're ready. Roger. We're ready for TV now. Turn it on. An onboard television camera provides additional means of crew observations and the public information in real time. During descent to the lunar surface, the crew in the lunar module communicates by two-way voice and by telemetry transmission with the orbiting command module and tracking stations on Earth. Once down on the surface, the link is expanded. It covers the astronauts outside the lunar module and through an erectable antenna, live telecasting can be made directly from the surface of the moon. Here, flexibility is the key. Astronauts on the moon, lone pilot in the orbiting command module, flight controllers on Earth, anyone, anywhere may talk with anyone else. Even if voice transmission is lost between the lunar module and earth stations, two contingency systems, emergency voice and emergency handed Morse code are available during liftoff from the moon. Rendevu and docking with the command module and the command module's return trip to Earth. There is direct lineofight voice contact with Earth tracking stations. As the command module plunges into the Earth's atmosphere, aerodynamic heating ionizes air particles around the spacecraft and this causes a brief blackout period when no communication is possible. This is Houston. That's negative. Still no contact. They're attempting to contact through a rise 7. Hello, Airbor. Hello, Airbor. Communications are resumed soon after for recovery with voice or beacon for direction finding and this may be with a ground station recovery aircraft or ship. Okay, it's been real fine. Just a final update on the weather and the recovery area. 2000 broken winds 270 at 20 wave height is 3 ft. Roger. Finally, when the spacecraft is down safely in the water, the shortest communication link of all is established between the astronauts in the command module and the frogmen outside. Accurate [Applause] and precise communication will always be a prime factor in the success of any space mission. It is true in an Apollo flight. In spite of all technological breakthroughs, it is still men who must make decisions. And their success in a lunar mission depends on how well these decisions are communicated and executed. [Music] [Applause]