TELLY LROM THE MOON

The video imagery of Neil Armstrong descending Eagle’s ladder and stepping onto the Moon is among the most famous of all news clips. However, commentators from more recent and media-savvy times are often astonished to learn that television, which would be of tremendous public relations importance, was almost pushed aside as a distraction to the exacting job of actually achieving the prime goal of the Apollo programme. Wally Schirra resisted having a TV camera on Apollo 7, but the success of black-and-white television from Apollo 8, which brought pictures of a distant Earth and of the Moon’s dramatically illuminated terminator to the public, sold the idea to NASA. These broadcasts drew massive audiences from around the world and NASA soon realised that TV could play an important role in shaping how history would remember Apollo.

Several months prior to the historic moonwalk by Armstrong and Aldrin, NASA had intended to send them to the surface with only a 16-mm movie camera and a spool of film that was insufficient to record the entire moonwalk. Max Faget, one of the spacecraft designers, described it as “almost unbelievable [that the mission] is to

be recorded in such a stingy manner". The pendulum swung towards acceptance of the technology in the spacecraft and on the lunar surface. The commander of Apollo 10. Tom Stafford, embraced the idea of TV from a spacecraft and helped to push the development of a colour TV camera that allowed him and his crew to make regular transmissions from their orbit around the Moon. This further raised the importance of television in the minds of crews and managers.

Despite this acceptance, the frantic pace of flight development and the difficulty of developing a lightweight colour camera for the harsh conditions on the lunar surface meant that the Apollo 11 lunar module Eagle took only a simple black-and – white TV camera to Tranquillity Base, while the colour unit remained in the comfy warmth of the command module.

In later years. Jack Schmitt was withering in his assessment of NASA’s overall reluctance to adopt TV. "The first Apollo TV camera was just ludicrous. NASA just totally screwed up the specs in buying the thing and there was no excuse for it. Finally, we got a good, high resolution camera for 15, 16, and 17. Actually, Tom Stafford flewr it on 10. But the so-called Apollo Television Camera that flew on Apollo 11 w-as terrible – low resolution, black-and-white. Just not any good at all. It couldn’t take any kind of bright scene at all. On Apollo 8. we had to put every filter in the spacecraft in front of it just to Lake a picture of the Earth.’’

The lesson had been learned, and from Apollo 12 onwards, colour TV cameras were taken to the Moon’s surface. To get TV back to Earth, engineers used a part of the bandwidth in Apollo’s radio system set aside for auxiliary signals, be it scientific data, recorded onboard data or television. Although both the black-and-white and the colour systems used this auxiliary communications channel, the implementation was very different.

Before describing how TV images reached our sets from the Moon, a cjuick lesson in terminology is in order. In the United States, conventional TV images were built up within a frame of 525 lines. A complete frame was sent 30 times per second but the lines within it w’ere not sent sequentially. Instead, all the odd-numbered lines were sent first, followed by all the even-numbered lines which meant that two interlaced scans of the image combined to make a frame. Each of these scans was called a field. To an approximation, the US television system of the late twentieth century had 60 fields per second of 262.5 lines per field, or 30 frames per second of 525 lines per frame although not all of those lines carried imagery.

All video imaging of the time was carried out by tube technology that generated electron beams within vacuum vessels. Ilot wires provided an electron source and coils of wire deflected the beam to scan the image. They were therefore hot, heavy and power-hungry.