by When the loneliest spaceship in the universe has a glitch, it’s not just about turning it off and turning it on again.
Voyager 1 – which in 2012 was the first human object to leave the Solar System – went silent in November, meaning no scientific or engineering data was being sent back to Earth.
The probe was sending vital data about the ‘stuff between the stars’ and the sudden loss of contact left NASA stumped.
The spacecraft is 15 billion miles away at a speed of under 32,000 mph, which means it takes 22.5 hours for any commands sent from mission controllers to reach the small probe, and when they arrive, the engineering team must wait again for an answer.
To make matters worse, Voyager 1 was built in the 1960s and 1970s, which meant that experts had to search the archives for decades for paper documents written by engineers who never anticipated the problems, or even had knowing that the explorer would travel this far.
But this week NASA’s Jet Propulsion Laboratory (JPL) announced that Voyager was operational again after receiving the most significant and longest-running software patch in history.
Back in business
Bill Kurth, Research Scientist at the University of Iowa, who has been a member of Voyager’s science team since 1974, told the Telegraph: “We were all excited to re-establish two-way communication with Voyager 1.
“The Voyager team at JPL has performed a miracle in recovering this amazing probe, which could lead to continued scientific discoveries.
“Now, we look forward to seeing the flow of scientific data from Voyager 1 in the coming weeks.”
NASA took more than five months to solve the problem. The initial idea in March was to give the spacecraft a ‘digital pocket’. Like a dentist blowing puffs of air on teeth to find cavities, the NASA team sent up an order asking the spacecraft to send a complete memory readout back to Earth, so that any contamination would stand out.
The revealed flaw was found in a chip in one of three computers on board Voyager, known as the flight data subsystem (FDS), which is responsible for packaging the science and engineering data before it is sent back to Earth.
Instead of returning science, temperature and engineering data, the glitch meant the computer was repetitively churning out binary ones and zeros as if it were “stuck.”
Ingenious gambling
As it was impossible to replace the faulty chip, NASA came up with an ingenious solution which involved inserting the affected code elsewhere in the FDS memory.
To complicate matters, however, no single location was large enough to hold the entire code section.
So, they came up with a plan to split the affected code into sections and store those sections in new locations in the computer system’s memory while making sure they could still talk to each other and work together.
After the software patch was launched, several dozen scientists and engineers gathered in a conference room at JPL in Pasadena, California to wait for the new signal. About 45 hours after fixing the fix, the team received confirmation that they were successful.
Linda Spilker, project scientist for NASA’s twin Voyager spacecraft told the Ars Technica website that ‘you could hear a pin drop’ in the room while waiting for the signal. When he finally arrived there were ‘tears of relief, high-fives and smiles.’
The team is not sure what caused the defective chip, but they think it could have been hit by an energetic particle from space or it could have been worn out after 46 years.
Humanity’s longest object
Voyager 1 and its sister spacecraft Voyager 2 were launched in 1977 to study Jupiter and Saturn.
The mission has since been expanded to explore the outermost limits of the Sun’s influence and beyond. Voyager 2, which also flew by Uranus and Neptune, is on its way to interstellar space.
Voyager 1 is mankind’s most distant object and if it is intercepted by any intelligent alien civilization, it will receive a gold-plated disc containing a series of multicultural greetings, songs and photos in 55 languages.
Among them is a message in Welsh and six languages which are now extinct.
The audio recordings include the sounds of footsteps across polished floors, a person’s heartbeat and someone laughing. There is the sound of a couple kissing and a mother with her child.
The disc even has the brain waves of Ann Druyan, creative director of the Voyager Interstellar Message Project, at the moment she decided to marry her husband. She described it as the thoughts of someone falling in love.
Powered by a nuclear battery, or Radioisotope Thermoelectric Generator (RTG), the spacecraft are the two longest-running spacecraft in history.
Voyager 1 is mostly studying cosmic rays, but the team is also excited about a strange anomaly in the data they’ve dubbed ‘primary thrust 2’ – a jump in plasma density and the magnetic field around the spacecraft.
NASA does not know if it is coming from the Sun or a phenomenon in interstellar space.
Dr. Kurth: “I certainly had no idea that these two spacecraft would continue to operate for over 46 years and continue to send vital scientific information back from beyond the Sun’s extended atmosphere or heliosphere.
“The Voyagers are making the only in situ observations of the ‘stuff between the stars’ ever, and these will probably not be made again for another 3 decades or more.
“We are learning about cosmic rays, thought to be from supernova explosions, the magnetic field around the heliosphere, the density of plasma, and the fact that the Sun can influence the interstellar medium for thousands of astronomical units even beyond the ellipsis.
“Each of these measurements raises new questions about the Sun’s galactic environment.”
