Who is the greatest explorer in human history? Christopher Columbus, Ferdinand Magellan, Captain James Cook?
You might be surprised to learn that the world’s greatest explorer is a machine built by NASA.
Make that two machines.
Mind you, not just any machines. A pair of machines that defied prediction, expectation and what was thought to be their own limitations.
Machines that can almost think for themselves, work tirelessly without sleep or rest. Going bravely where no one has ever gone. Time and space machines in the truest sense.
The Universe is a pretty big place. But two space probes, each of them the size of a Volkswagen Beetle, made it just that little bit smaller and all of us, small as well.
Voyager 1 and 2, launched in August of 1977, were tasked with taking colour photographs and measurements of Jupiter and Saturn. But these two spacecraft were never destined to be ordinary, whatever they might have achieved. Fifteen hundred engineers worked for five years to build them at a cost of $200 million. Of course if they managed to run rings around Saturn and Jupiter, pardon the pun, they would be pressed onward into uncharted territory. Very uncharted territory.
In the beginning, after launch, both Voyagers performed flawlessly. But the budget for their mission was always tight. The Voyagers needed 200 engineers working full time to shepherd both craft to their destination. Instead, what they got was a kind of dumping ground for new University graduates who suddenly had the responsibility of controlling some of the most sophisticated state of the art electronics at that time.
According to Murphy’s law, anything that can go wrong, will. In April 1978, Voyager 1, not even half way to Jupiter, experienced a major meltdown. Its scan platform, for mounting all of its cameras and instruments, became jammed. While engineers tried to figure out what they could do to fix it, from more than 100 million miles away, someone forgot to send a weekly command to reset a timer on Voyager 2.
When they built the two Voyagers, engineers gave them attitude and some personality. When Voyager 2 didn’t hear from any human, it did what it was programmed to do. The spacecraft triggered its protection software, 600 lines of coded information that respond to malfunctions automatically.
In this instance, Voyager 2 assumed that its radio receiver was broken and switched to the backup. Meanwhile, back on earth, the engineers realised they made an error and tried to stop the fault protection routine. But the newly awakened backup receiver would not register their command. Their only hope was that the spacecraft would eventually reason its way back out of its predicament. To their astonishment, the main receiver did precisely that, only to suffer an electrical short out.
But like all well made pieces of ancient artificial intelligence, Voyager 2 refused to die. The engineers figured out that Voyager 2’s malfunctioning backup receiver ( the one that worked) still had an electrical pulse. But its problem was the tyranny of distance from earth. Voyager 2 struggled to recognise commands. So the engineers re-calibrated their signal, manually subtracting the Doppler effect on the passage of radio waves and tried sending it to Voyager 2 who ( I like to think of the Voyagers as people) completely understood and began functioning normally again. But to this day, that same complicated calculation must precede every command sent to Voyager 2.
At the present time, the two Voyagers, after conquering Saturn and Jupiter and sending back never seen before images from both planets. are 10 billion and 13 billion miles respectively from earth. The farthest that any man made object has travelled. This month is the 40th anniversary of the Voyagers launch. And still they fly on. To get a full appreciation of what that means, you need a brief lesson in astro physics. Space might appear to be vacant, but in fact it’s matter created by the explosion of ancient stars.
Within the neighbourhood of planet Earth, our bit of space has different particles from elsewhere because of the supersonic winds that blow from the surface of the Sun. The winds generate a bubble around our solar system, called a heliosphere. Five years ago, Voyager 1 reached the boundary of where the heliosphere gives way to interstellar space. It is a region as new to us as the Pacific was to the Europeans five hundred years ago.
And while they are poised on the very doorstep of a new frontier, the Voyagers gather data that continues to challenge fundamental physics and may provide clues to a couple of very big and important questions: Is the Sun only linked to the birth of life in our solar system? Where else are we most likely to find evidence that we are not alone?
The two Voyagers are true stellar explorers, who earned the title of making mankind’s greatest journey. Most of their flight crew, remained on the program almost from the beginning. Why would you leave? They’ve shared in the glory of being the world’s greatest living explorers. They are almost certainly the only people in the world who can still operate the Voyagers archaic onboard computers. To give some idea of what they are dealing with, these computers have 235 thousand times less memory and 175 thousand times less speed than a 16 gigabyte smartphone. And while the nine member flight crew, strictly speaking, haven’t gone anywhere themselves, their work is no less arduous than any 15th century European explorer. Magellan never had to steer his ship from the confines of a rented office nor did he stay at the helm long enough to qualify for a senior discount at the McDonald’s burger joint next door.
The flight crew’s fluency in grossly out of date computer language. becomes more and more crucial with the passage of time. As the Voyagers continue to keep on keeping on and harvest data, they are finally running out of fuel. Decaying plutonium is their power supply. By 2030 they will not have enough power to run a single experiment. We can only hope their flight crew, who are fast approaching retirement age, if they aren’t there already, live long enough to squeeze out every last available watt. We wouldn’t want to miss out on anything that might be discovered, and neither would they.