The fantastic Voyager

Voyager One left earth in 1977 on a five-year trip to Jupiter. eleven billion miles later, it is set to become the first man-made object to leave our solar system. Jonathan Brown tells its remarkable story It is a journey that will never end and it began on August 20 1977, at the Kennedy Space Centre in Cape Canaveral, Florida when a Titan-Centaur rocket blasted into a clear blue sky. Back then the excited scientists had what now seem like relatively limited hopes for the payload spiralling above them in a plume of white smoke.

Voyager One, which was launched two weeks after its sister probe Voyager Two, was meant to exploit a rare geometric arrangement of the outer planets occurring just once every 175 years.

This unusual alignment meant that a space ship could "swing by" Jupiter and Saturn with the help of gravity. It would give NASA scientists and those at the Jet Propulsion Laboratory near Los Angeles, or so it was hoped, the first ever close up view of our "neighbourhood" - Saturn's rings and the larger moons of the two planets.

But Voyager's journey did not stop there. It was a time of renewed interest in space travel - certainly in the public's mind - with cinema audiences queuing for a glimpse of the newly released Star Wars.

Yet even the most optimistic of the Nasa engineers who had salvaged the Voyager project out of the budget-cut remnants of the Planetary Grand Tour program of the 1960s, could have envisaged that the science they were conducting might echo the fantasies of George Lucas's cinematic fiction.

Today, after nearly 35 years in perpetual motion, armed with a computer boasting just a fraction of the processing power of the average smart phone, Voyager One is poised to open up a new frontier in man's exploration of space.

The 775kg probe is still sending back data despite the ravages of its fantastic voyage. Now it is on the brink of interstellar space.

Hurtling at more than 10 miles per second it is currently immersed in the foamy walls of the heliosopheric bubble - an area where charged particles blown off the Sun come up against the stellar winds blowing through the remainder of the galaxy.

In other words it has reached the edge of our solar system and is set to penetrate into a new and unvisited area of the cosmos previously only observable through powerful telescopes. Dr Edward Stone of the California Institute of Technology in Pasadena is now in his late 70s but retains a central role in the Voyager project for which he was the original chief scientist. "When the Voyagers launched in 1977, the space age was all of 20 years old," he explained recently.

"Many of us on the team dreamed of reaching interstellar space, but we had no way of knowing how long a journey it would be - or if these two vehicles that we invested so much time and energy in would operate long enough to reach it," he added.

NASA originally created two vehicles believing one was likely to perish. It also estimated they might work for five years. A veteran of 14 NASA missions, Dr Stone's enthusiasm remains undimmed. "The laws of physics say that someday Voyager will become the first human-made object to enter interstellar space, but we still do not know exactly when that will be," he said.

"The latest data indicates we are clearly in a new region where things are changing more quickly. It is very exciting. We are approaching the solar system's frontier."Voyager One completed its key landmarks more than three decades ago.

- The Independent