47 years and eight months after its launch, Voyager 1 continues to push the limits of what seemed possible. Currently 24.88 billion kilometers from Earth – 166 times the distance between Earth and the Sun – Voyager 1 is the farthest human-made object from our planet. The legendary NASA probe, launched in 1977 alongside its twin, Voyager 2, is set to have its mission extended a little longer since engineers at the Jet Propulsion Laboratory (JPL) announced on May 14 that they had successfully revived, remotely, a thruster critical to the spacecraft's survival.

Voyager 1 navigates using the positions of stars, which it can read by controlling its roll – that is, its rotation relative to the axis of its antenna – using two thrusters (a main and a backup).

Over time, leftover propellant residue deposited after each firing gradually clogged the narrow inlet pipes of the main thruster. This forced engineers to switch both Voyager 1 and 2 to their backup roll thrusters to keep them pointed at their guide stars. But the backup thruster itself gradually became "clogged," leaving the ground team with few options, especially since the main system failed in 2004. At the time, engineers concluded that the failure was "probably irreversible."

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