"The batteries were dying and I knew that if we had to rotate one more time, that would be it," says Southworth. "At that point I was a bit pessimistic."

Eventually, despite intermittent communications caused by the spinning, the team managed to adjust the speed of the other reaction wheels.

"That was the moment when I thought, this has to work or we're done for," says Southworth.

"After hours and hours, and a lot of people involved in the fight," says De Marco, "we managed to get the satellite back under control.

Since then, Integral has been operating well. But what if something goes wrong when your elderly spacecraft is around a distant world 150 million km (93 million miles) away?

Launched in 2003, Esa's Mars Express was designed to orbit Mars for two years. After nearly 20, the mission has investigated the atmosphere and delivered stunning imagery of the Martian surface, as well as acting as a relay for a series of Nasa rovers.

Like their colleagues, controllers have also had to cope with elderly computer systems. Following a glitch with its onboard computer, for instance, engineers worked out a new way of loading commands into the spacecraft's 2MB RAM memory (just by way of comparison, an iPhone 14 starts at 128GB – which is 64,000 times more memory).

They also discovered that the original software for part of the onboard navigation system was running on a Windows 98 PC that no-one could find the password to and ended up using bolt cutters to extract the hard drives. But the biggest challenge came five years ago and, once again, it was a mechanical failure that threatened to bring the mission to an untimely end.

Mars Express is fitted with six gyroscopes to measure rotation. Together with two cameras – known as star trackers – these enable the spacecraft to determine its orientation in space. But by 2017 it was clear the gyros were failing.

"We had this big meeting to discuss the state of the spacecraft and it was concluded that it had two years left to live," says spacecraft operations engineer Simon Wood. "It was a pretty depressing meeting to come out of."

Fortunately, the spacecraft was built to a standard design which was also used for other missions including the cometary explorer, Rosetta. Although Mars Express was never designed to operate without its gyros, Rosetta's software allowed its gyros to be turned off. So, could they hack code designed more than 20 years ago for Rosetta and make it work for Mars Express?

"Most of our colleagues thought we were mad because the very idea that you would go elbow deep into on-board software source code was almost unheard of," says Wood. "But we stuck at it."

In 2018, they prepared to upload the software and reboot the spacecraft. "The spacecraft hadn't been restarted from cold for 12 years, so it wasn't without its risks," Wood says. "It works better than we ever dared hope and we now have a mission extension until 2028."

But another mission in orbit at Mars has lasted even longer. With 95,000 orbits on the clock, Nasa's Odyssey is the oldest operating spacecraft in orbit around another planet.

"I feel very fortunate to have such a robust robot at Mars," says mission project scientist Jeffrey Plaut, who calls the current phase a "golden age" of Mars exploration. "The mission was only expected to last a handful of years and it's gratifying because it allows us to do science we never expected to do, in particular long-term monitoring of the weather and climate at Mars… it's really quite remarkable."

Plaut has been working on Odyssey since it arrived to Mars' orbit in 2001, but the current operations team, based at JPL in Pasadena, has only been on the mission for 18 months after the previous incumbents retired and passed on the baton, alongside decades of wisdom.