Earth’s most distant spacecraft, Voyager 1, has started communicating properly again with Nasa after engineers worked for months to remotely fix the 46-year-old probe.
Nasa’s Jet Propulsion Laboratory (JPL), which makes and operates the agency’s robotic spacecraft, said in December that the probe – more than 24 billion km away – was sending gibberish code back to Earth.
In an update released on Monday, JPL announced the mission team had managed “after some inventive sleuthing” to receive usable data about the health and status of Voyager 1’s engineering systems. “The next step is to enable the spacecraft to begin returning science data again,” JPL said. Despite the fault, Voyager 1 had operated normally throughout, it added.
Launched in 1977, Voyager 1 was designed with the primary goal of conducting close-up studies of Jupiter and Saturn in a five-year mission. However, its journey continued and the spacecraft is now approaching a half-century in operation.
Voyager 1 crossed into interstellar space in August 2012, making it the first human-made object to venture out of the solar system. It is currently travelling at 60,821km/h.
The recent problem was related to one of the spacecraft’s three on-board computers, which are responsible for packaging the science and engineering data before it is sent to Earth. Unable to repair a broken chip, the JPL team decided to move the corrupted code elsewhere, a tricky job considering the old technology.
The computers on Voyager 1 and its sister probe, Voyager 2, have less than 70 kilobytes of memory in total – the equivalent of a low-resolution computer image. They use old-fashioned digital tape to record data.
The fix was transmitted from Earth on April 18th but it took two days to assess if it had been successful as a radio signal takes about 22½ hours to reach Voyager 1 and another 22½ for a response to come back to Earth.
“When the mission flight team heard back from the spacecraft on 20 April, they saw that the modification worked,” JPL said.
Alongside its announcement, JPL posted a photo of members of the Voyager flight team cheering and clapping in a conference room after receiving usable data again, with laptops, notebooks and doughnuts on the table in front of them.
The Retired Canadian astronaut Chris Hadfield, who flew two space shuttle missions and acted as commander of the International Space Station, compared the JPL mission to long-distance maintenance on a vintage car.
“Imagine a computer chip fails in your 1977 vehicle. Now imagine it’s in interstellar space, 15bn miles away,” Mr Hadfield wrote on X. “Nasa’s Voyager probe just got fixed by this team of brilliant software mechanics.
Voyager 1 and 2 have made numerous scientific discoveries, including taking detailed recordings of Saturn and revealing that Jupiter also has rings, as well as active volcanism on one of its moons, Io. The probes later discovered 23 new moons around the outer planets.
As their trajectory takes them so far from the sun, the Voyager probes are unable to use solar panels, instead converting the heat produced from the natural radioactive decay of plutonium into electricity to power the spacecraft’s systems.
Nasa hopes to continue to collect data from the two Voyager spacecraft for several more years but engineers expect the probes will be too far out of range to communicate in about a decade, depending on how much power they can generate. Voyager 2 is slightly behind its twin and is moving slightly slower.
In roughly 40,000 years, the probes will pass relatively close, in astronomical terms, to two stars. Voyager 1 will come within 1.7 light years of a star in the constellation Ursa Minor, while Voyager 2 will come within a similar distance of a star called Ross 248 in the constellation of Andromeda. – Guardian