Thu, Oct 25, 2012 - Page 9 News List

Voyagers carry on legacy of the human race

Thirty-five years after leaving Earth, Voyagers 1 and 2 have reached the very edge of the solar system. The two antiquated probes are likely to outlive us, and perhaps even the Earth itself; the only record of our existence, circling the galaxy forever

By Dallas Campbell and Christopher Riley  /  The Guardian

Illustration: Mountain People

The year 1977 was an important one for music. Fleetwood Mac’s Rumours and the Sex Pistols’s Never Mind the Bollocks were released. Elvis left the building for the last time, dying at the age of only 42. Amid all this rock’n’roll history, another less celebrated, but far more significant album was quietly being made.

Fashioned from copper rather than vinyl and plated with gold for longevity, The Sounds of Earth was compiled by US astronomer Carl Sagan. It was a broader range of music than most of the other albums released that year, aiming to encapsulate 5,000 years of human culture; from an Australian Aborigine song and an Indian raga to Azerbaijani bagpipes, bamboo flutes, Johann Sebastian Bach, Ludwig van Beethoven and Chuck Berry.

Like any compilation album, each piece was carefully selected and its merit, to make the cut, hotly debated. Yet unlike most other records, only two copies were made. They were placed inside their aluminum album covers, complete with artwork in the form of a “clear,” universally understandable, pictorial depiction of what they were and instructions for how to play them. A stylus was also included, to help any creatures that might chance upon them in the future to hear the music and other recordings. In a scene that would not have been out of place in Ridley Scott’s recent film Prometheus, they were then carefully bolted to the outside of the two Voyager spacecraft by the last human beings ever to touch them.

The records sit on one face of each craft’s 10-sided “chassis,” or bus, above which sits the large, white 3.7m wide communications dish, which dominates the structure. Protruding, insect-like, from the craft are “limbs” and antennae. The radioisotope thermoelectric generators, which power the Voyagers in the darkest reaches of the outer solar system, stretch out to on one side, just below a proboscis-like, 13m long magnetometer boom. Across the other side of the craft, another broad arm juts out. It carries Voyager’s “eyes” — an array of cameras, spectrometers, particle detectors and other equipment.

The challenge for NASA’s Jet Propulsion Lab (JPL), which designed and constructed the Voyagers, was to build a craft that could survive in space for years. In the early 1970s, when the JPL team began the project, they had never built a craft rated for longer than a few months of interplanetary travel. It was a big jump to create something that would reach the outer planets and perhaps even farther.

“At that point in time, that was a mind-blowing thought,” Voyager systems engineer John Casani said.

“How you build a spacecraft that can survive failures and still keep on chugging. We thought we could do it. Nobody else did,” he said.

Half a decade of back-breaking building and testing followed to create a craft which was up to the job. As the build was nearing completion, Casani decided to do something unique to celebrate the sacrifices his 2,000-strong engineering team and their families had made. During an open house party held to mark the end of Voyager’s design phase, he invited everyone to sign their names on large sheets of paper. These were then reduced and reproduced onto six small metal plaques, still large enough to read the individual names. They were then stitched into the thermal blankets inside the main spacecraft, as a memorial to those whose ingenuity, skill and support had made these unique machines possible.

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