NOW, VOYAGER

NASA launched Voyager 1 on September 5, 1977, about two weeks after its sibling craft, Voyager 2. More than 46 years later, Voyager 1 is more than 15.1 billion miles from Earth and travels farther away at 38,027 miles per hour, more than 3,000 miles per hour faster than Voyager 2, located 12.67 billion miles from Earth.

Today, communication with the probe is failing, as the Flight Data System, which controls onboard systems, has stopped sending data back to Earth. With a communication delay of almost 23 hours, one way, it may prove impossible to rectify the issue. The technical issue is compounded by the age of the technology - most of the team who originally worked on the project are now dead and the manuals and data for the project only exist in hardcopy files. Voyagers nuclear batteries will shortly fail too, as solar energy is so weak, the probe needed to rely on onboard power.

Voyager 1 and 2 are the most remote man-made craft ever and are now around 22 billion miles away in deep space, at the point of heliopause, where the suns influence is no longer perceptible.

The twin probes are responsible for some of the most amazing images of the outer planets and until other craft visit the outer solar system, the only clear images we have of the ice giants, Neptune and Uranus. Voyager discovered the ring system and several new moons on the outer planets and showed the Jovian and Saturnian satellites with unprecedented clarity.

Even if communication ultimately fails to be restored with the probe and its fellow traveller, it will have made a massive contribution to our understanding of space.

From the late seventies onward, all books featured a section on the Voyager missions, with early volumes showing projected mission outlines and later publications showing some of the astonishingly clear images from the craft.

One of the probes photographs shows Earth taken Feb. 14, 1990, by NASA's Voyager 1 at a distance of 3.7 billion miles (6 billion kilometers) from the Sun. Literally a 'Pale Blue Dot'.

Both probes carry a 'gold disk' featuring symbolic representations of data and a recording of 'Sounds of Earth', curated by Dr Carl Sagan, along with 115 different images, such as 'People Eating' to represent human society.

Some of the planetary imagery has yet to be surpassed in quality, even by the current space based telescopes, such as James Webb and Hubble.

Both probes are currently in interstellar space and leaving the solar system at almost 40,000 mph.