Voyager 1 is one of the most successful space missions of all time. (See the Bad Astronomy blog and NASA for lots more detail.) Launched in 1977, it visited Jupiter and then Saturn, providing better close-ups of the two planets than had ever been seen before. But it sailed on, crossing the orbits of both Uranus and Neptune (its sister, Voyager 2, actually flew by these two planets). Now after 33 years, it is 17 billion kilometres (10.6 billion miles) from the Sun and has reached the point where the solar wind has slowed to a stop. In another 3-4 years it will truly be in interstellar space and entirely beyond the sun’s influence.
Just imagine! Voyager was built and launched before personal computers were everywhere (it was 4 years before IBM PC was announced), before cell phones were a commodity and when the internet was still a research and defence tool! It is based on Z80 (remember the Sinclair ZX80?) and/or 1807 computer chips. It is still phoning home to send back streams of useful data and its battery/power supply is expected to last until 2025 – that’ll be almost 50 years in service! Even more amazing is the thought that Voyager 1 has already been flying for almost a third of the time since the Wright Brothers first heavier than air flight in 1903.
And Voyager 1’s sister Voyager 2 is doing much the same, but flying in a totally different direction. What’s more earlier this year engineers reset the software in Voyager 2 to correct a fault which was corrupting its data transmissions. And that’s with a transmission delay of around 15 hours! – so 15 hours for the signal to reach Voyager and at least another 15 hours before you know if its received and working.
On top of that these two spacecraft are fractionally not where they should be according to our best theories of ballistics. That in itself is proving to be interesting new science as the cosmologists try to understand why this is.
As one a commenter at Bad Astronomy says:
I’m not sure what’s most amazing – that this machine is still working after 30 years in deep space (hell, how many machines do you know that can work non-stop without maintenance for 30 years in a nice warm garage?), the incredible distance that this probe has brought our eyes to by proxy, the fact that it’s literally leaving the breath of the sun behind and venturing into the still coldness of interstellar space, or the fact that we can actually communicate with the probe over such distances.
However you look at it this is some stunning achievement!