The four Cluster satellites were launched in 2000 and were orbiting Earth in a tight formation until last March when the Cluster’s number 3 satellite, Samba, failed to switch on, causing controllers to lose contact with the satellite. Each of the satellites carries an identical payload to monitor Earth’s space environment and its interaction with solar wind.

   “With no status data and no response from the instrument, we suspected either that the device’s five power switches were locked closed or a failure caused by an electrical short circuit, one of the most dangerous faults on any satellite,” ESA Cluster Operations Manager Jürgen Volpp said in a statement.

   Volpp said the solution to the problem was based on a dirty hack (meaning any non-standard procedure) via a series of commands that helped flipped the power switches on and bring the satellite back to life. “Cluster has since returned to normal operation and measures are being taken to prevent this failure from happening again,” he said.