Posted by: Footler PJ4 AUG 2010
Do you remember when contacting someone in foreign parts involved booking calls with overseas operators then hoping for the best but fuming as the connection crackled and died?
Did you send telegrams, compressing words and phrases to save a few pence, or write letters on lightweight airmail paper only to wait ages for a reply? And how new was the news when it arrived?
Nowadays we take instant global communication for granted. We can watch faraway wars, natural disasters and sporting events as they happen. We have internet cafés in out-of-the-way places and instant messaging.
A major step in the development of this service happened 50 years ago, on 12 August 1960, when NASA launched Echo 1, its first experimental reflector satellite. Echo 1 was a 30.5m diameter balloon made of Mylar polyester coated with aluminium. It carried a set of 107.9 MHz transmitters powered by nickel-cadmium batteries and solar cells. It acted as a passive reflector to bounce telephone, radio and television signals from one point on Earth to another. This was only 10 years after the first live television pictures had been transmitted across the English Channel.
Echo 1 may have looked like a simple glitter ball but it proved that microwave signals could be transmitted to and from satellites in space. It also demonstrated the ground station and tracking technologies that would be needed to make communication via satellites possible.
Echo 2, a slightly larger Mylar balloon, continued these experiments while helping to develop the techniques needed to manoeuvre spacecraft. Both satellites later re-entered the Earth’s atmosphere but by then attention had moved on to today’s active communication satellites which amplify and retransmit the signals.