Voyager 1 still reporting back from interstellar space, 40 years after its launch
Voyager 1, the only spacecraft ever to venture beyond the solar system, will mark its fortieth anniversary next month.
Humanity’s most far-flung ambassador was launched on 5 September 1977 and finally left the solar system five years ago.
Its twin, Voyager 2, which blasted off the Earth on August 20 1977, is expected to enter interstellar space in the next few years.
Both craft have long-lasting nuclear-powered batteries and continue to communicate with the US space agency across billions of miles.
Voyager 1 is now almost 13 billion miles from Earth, travelling northward in relation to its home planet at more than 30,000 mph. The craft has informed its controllers just how harsh the interstellar environment is, with cosmic radiation levels four times higher than they are around the Earth.
In about 40,000 years, the probe is expected to fly past a star 17.6 light years away called AC+79 3888 in the constellation Ophiuchus.
Voyager 2 is almost 11 billion miles from Earth and travelling in the opposite direction, allowing scientists to compare the two regions of space.
Thomas Zurbuchen, associate administrator at Nasa’s Science Mission Directorate, said: “I believe that few missions can ever match the achievements of the Voyager spacecraft during their four decades of exploration.
“They have educated us to the unknown wonders of the universe and truly inspired humanity to continue to explore our solar system and beyond.”
Voyager 2 is the only spacecraft to have flown by all four outer planets, Jupiter, Saturn, Uranus and Neptune. Between them, the spacecraft have made numerous discoveries including the first active extra-terrestrial volcanoes on Jupiter’s moon Io, hints of a subsurface ocean on Jupiter’s moon Europe, an Earth-like atmosphere on Saturn’s moon Titan and icy geysers on Neptune’s moon Triton.
Controllers expect to have turned off the last Voyager science instrument by 2030, but even then the craft will continue silently coasting on an endless odyssey that will see them complete an orbit of the Milky Way galaxy every 225 million years.
Voyager project scientist Ed Stone, based at the California Institute of Technology, said: “None of us knew, when we launched 40 years ago, that anything would still be working and continuing on this pioneering journey.
“The most exciting thing they find in the next five years is likely to be something that we didn’t know was out there to be discovered.”