The Voyager space probes – Voyagers 1 and 2 – that are heading out of our galaxy and off after a 45-year mission to go where no one has gone before.
The identical little spacecraft – each equipped with a gold-plated LP featuring bird song and music to explain to alien life who we are on Earth – remain a marvel, a remnant of the ambitious United States space programme of the 1960s from an era before microprocessors.
“We cast this message into the cosmos,” a message from then US president Jimmy Carter reads on the craft, according to Scientific American.
NASA scientists are progressively turning off various sensors and instruments on the little craft as they speed towards the very edge of our galaxy – the heliosphere, a border that we don’t fully understand between our solar system and the rest of the universe – in an effort to extend their lifespan into the 2030s.
Voyager was conceived in the mid 1960s, in the wake of the Soviet Union launching the first satellite, Sputnik, eight years before. It was intended to take advantage of an unusual alignment of Earth with Jupiter, Saturn, Uranus, and Neptune that would allow a craft to use the gravitational pull of those planets to skip along them. The alignment only occurred every 176 years and its importance was realised by Gary Flandro, then a doctoral student at the California Institute of Technology who worked part time at NASA’s Jet Propulsion Lab in Pasadena.
“Using a favourite precision tool of 20th-century engineers — a pencil — he charted the orbital paths of those giant planets and discovered something intriguing: in the late 1970s and early 1980s, all four would be strung like pearls on a celestial necklace in a long arc with Earth,” writes Scientific American’s Tim Folger.
Identical Voyager 1 and 2 space probes launched within 15 days of each other in 1977. On a mission expected to survive four years, they lasted 10 times that and dramatically expanded our knowledge of the solar system, planetary moons, and now interstellar space They’re now more than 12 billion miles from Earth, still communicating regularly, if weakly, back to us, despite being equipped with only 69 kilobytes of memory, “less than a hundred-thousandth the capacity of a typical smartphone”.
It was Voyager 1 that captured the image of Earth as a tiny pixel of light – 3.8 billion miles behind it – which the astronomer Carl Sagan described as “the pale blue dot”. Now the two Voyagers will give us insight into the boundaries between our galaxy and the next.
Courtesy of The Spinoff
