SA boffin unearths a gem in the space junk

Hundreds of instructions were transmitted into space in an instant from a little-known radio transmitter just outside Pretoria.

"Download files now; it i s safe to descend," the computer in the command module of the unmanned Apollo test mission, riding atop a Saturn AS202 rocket, was told as it orbited 1620km above the Earth.

The computer was among the most powerful then in existence and one of the first to incorporate microchip technology - but that was 50 years ago.

The signals were being transmitted from Nasa's Deep Space Station 51, now the South African National Research Foundation's Hartebeeshoek Radio Astronomy Observatory.

Responses to mission control's orders were mediated by the spacecraft's computerised guidance system, the world's first.

This system, operated on August 25 1966 for an hour and a half, was the forerunner of systems that would later get humans safely to the moon and back.

A key component of the system, its permanent memory, is now in the hands of Pretoria technology archaeologist and computer programmer Francois Rautenbach.

It was rescued by a US citizen who bought it, with 3t of other space junk, from a scrapyard dealer in Houston, Texas.

The scrapyard owner was planning to melt the junk to recover the valuable metals it contained.

The computer memory was in the form of rope memory modules, which exploit a long-obsolete technology.

For technology archaeologists such as Rautenbach, the data they contain is invaluable in that it gives a glimpse into the past and the thinking of the inventors of half a century ago.

"This was the world' s first computerised guidance system," said Rautenbach.

"It was used in submarines to give them precise locations and directions, in exactly the same way [it was] used on the Apollo test flight."

For the past 18 months Rautenbach, who obtained the rope memory modules after meeting their owner on eBay, has been analysing the data they store.

Afraid that if he tried to open up the devices he would damage them and lose the data, he X-rayed them using a hospital machine. His next step was to build himself a rope memory module reader.

With no documentation to explain the data structures, it took Rautenbach 18 months of trial and error, using different wiring connections and electrical pulses, to figure out the exact meaning of the data, which were represented in binary code - sequences of 1s and 0s.

"What we have inside these devices is what ultimately led to the development of today's computers and cellphones," said Rautenbach.

He said that for decades Nasa thought it had lost the memory modules devices.

From the data in the modules, and documents he obtained over the internet, Rautenbach learned that, at its highest point during its flight, the spacecraft was travelling over South Africa.

"At this point the computer was told that everything was OK and that the descent could begin."

Rautenbach plans t o make the data available on the internet once he is finished analysing them.

"The data canno t be used to do anything now but they give an insight into how things worked back then, of how we arrived where we are today and of where we are going in terms of technology."