Launched in 1977, Voyager 1 is now losing contact but will sail on

The computers on the Voyager 1 spacecraft, considered state-of-the-art back in 1977 — the year Elvis left the building for the last time — have 240,000 times less memory than an iPhone

After nearly 50 years, Voyager is still communicating with ground control on Earth 

The radio antenna, protruding from the central circular dish like the antenna on a robotic insect, is equally archaic, emitting as many watts as a refrigerator lightbulb

Ponder that for a moment when you cannot get a signal on your mobile or the Wi-Fi disconnects.

In one respect, though, Voyager 1 (well, in reality, the craft's Nasa handlers) has embraced the digital age, utilising X (formally Twitter) to tell its story. 

'There's just something about the vastness of space that really makes you contemplate your place in the universe,' NASAVoyager posted, philosophically, in a recent tweet.

Voyager, however, is starting to show signs of old age and, for now, has stopped transmitting effectively. 

The usable data it sends back in binary code has carried no meaning since last year. Nasa engineers are optimistic they can fix this problem, though, which emanates from a single computer chip.

But even when Voyager's nuclear batteries (using electricity generated from heat produced by the decay of the lump of plutonium powering Voyager) die in the next few years, and the umbilical cord with Earth is cut for good, the spacecraft will continue to float through the universe in perpetuity, whatever fate befalls mankind.

Long after the pyramids have crumbled into the desert, the oceans have boiled over, if indeed they do, and the last breath of humanity has been extinguished, Voyager, not withstanding an unforeseen disaster, will still be moving ever onward on its grand tour to infinity and beyond, a silent ambassador of our existence in the Milky Way.

Onboard is a record of what life was like on Earth: a gold-plated copper disc resembling a vinyl LP, complete with a stylus, intended for any alien civilisations Voyager might encounter during this odyssey into the future.

The 'compilation album', put together by legendary astronomer and planetary scientist Carl Sagan, features everything from Azerbaijani bagpipes to the sound of humpback whales. Music includes Beethoven, Mozart, Bach, gospel blues singer Blind Willie Johnson and Chuck Berry.

The choice of Beethoven's Cavatina has particular synergy. While the project was being researched, the composer's diaries were chanced upon in the archives of the New York Times, in which he had written: 'Will they like my music on Venus? What will they think of it on Uranus?'

But there is no Elvis Presley, who died in 1977, or The Beatles.

Sagan and his team wanted to follow the example of Voyager's predecessors, Pioneer 10 and 11, which famously had a naked man and woman emblazoned on plaques attached to their sides, but politicians found them too smutty so only a silhouette of a man and woman were put on the 'golden disc' to depict an 'essential part of the nature of humanity'. How attitudes have changed.

Two Voyager spacecraft were launched in 1977 to explore the planets in the outer solar system

As part of Nasa's mission in the summer of 1977, two spacecraft, Voyager 1 and Voyager 2 — identical in every detail — were launched within 15 days of each other.

Voyager 2 launched first on August 20, on a slower and longer trajectory than its sister probe. It is now more than 12 billion miles from Earth. Voyager 1 was launched on September 5.

It now takes more than 22 hours for a message to reach Voyager 1 and 22 hours for a response to make it back (at least, that's what happened before it was beset by recent technical problems).

The lift-off dates were chosen to take advantage of a rare alignment of Jupiter, Saturn, Uranus and Neptune — something that happens only once every 175 years — allowing the probes to visit all four planets.

One of the many extraordinary facts about the project is that both Voyager 1 and Voyager 2 were primarily constructed for a four-year mission.

'Nasa didn't want anybody spending time or money on anything that went beyond the baseline mission,' said engineer Chris Jones, who began working on the craft four years before their launch. 'That's all we were allowed to charge for.'

Yet, 46 years on, the mission is still in its infancy. The next closest star after the Sun is more than 40,000 years away, which puts that statement into perspective.

Of all the images sent back to us down the years, perhaps the most iconic — and humbling — is the one taken on Valentine's Day 1990 when Voyager 1, then 3.7 billion miles from the Sun, turned the cameras around and took a photo of Earth distilled into a single pixel which became known as the 'pale blue dot' and the farthest picture ever taken of home.

A 3D illustration of a Voyager 1 spacecraft in deep space field

A photo taken by a Voyager 1 spacecraft - as part of Nasa's mission in the summer of 1977, two spacecraft, Voyager 1 and Voyager 2 — identical in every detail — were launched within 15 days of each other

You cannot gaze at the pale blue dot, initially mistaken for a speck of dust, without being struck by how fragile and small our place is in the cosmos.

Moreover, to quote lead project scientist Ed Stone, 'few expeditions in the history of mankind have notched up so many scientific achievements as the twin Voyager probes.'

The spacecraft might be frozen in the technology of the 1970s, but, as he pointed out, Voyager 1 'was the first computer-controlled spacecraft ever launched and it still flies itself, it runs itself, it checks itself and it can switch to back-up systems by itself'.

During the 1980s, it provided new insights into the red spot on Jupiter as well as the celebrated rings around Saturn and the fact that these planets, unlike Earth, have many moons.

Where exactly are the Voyagers now? They passed through the 'heliosphere' a few years ago, considered by some to be the edge of the solar system, the cosmic equivalent of the doldrums where the high-speed solar winds are becalmed and where nothing terrestrial has gone before.

'The objective is to keep them flying as long as possible,' said one programme manager.

'You can imagine them being twins... one has lost hearing, the other doesn't see so well, so we will have to be very careful.'

Among the messages on the 'golden disc' is one from the late Jimmy Carter, who was U.S. president at the time.

'This is a present from a small, distant world,' he wrote, 'a token of our sounds, our science, our images, our music, our thoughts and our feelings. We are attempting to survive our time so we may live in yours.'

These words seem especially relevant in our age of nuclear brinkmanship — but will there be anyone out there to read them?