Engineers at NASA say they have successfully revived thrusters aboard Voyager 1, the farthest spacecraft from our planet, in the nick of time before a planned communications blackout.
A side effect of upgrades to an Earth-based antenna that sends commands to Voyager 1 and its twin, Voyager 2, the communications pause could have occurred when the probe faced a critical issue — thruster failure — leaving the space agency without a way to save the historic mission. The new fix to the vehicle’s original roll thrusters, out of action since 2004, could help keep the veteran spacecraft operating until it’s able to contact home again next year.
Voyager 1, launched in September 1977, uses more than one set of thrusters to function properly. Primary thrusters carefully orient the spacecraft so it can keep its antenna pointed at Earth. This ensures that the probe can send back data it collects from its unique perspective 15.5 billion miles (25 billion kilometers) away in interstellar space, as well as receive commands sent by the Voyager team.
For anybody else curious;
Voyager 1 uses hydrazine (N₂H₄) as fuel for its small attitude control thrusters. Hydrazine is a hypergolic monopropellant, meaning it doesn’t require an external oxidizer—it decomposes exothermically upon contact with a catalyst, producing gas to generate thrust.
The thrusters are not used for propulsion, but rather to rotate and stabilize the spacecraft so that its antenna remains pointed toward Earth and its instruments can be properly oriented. Fuel consumption is extremely low—only a few grams per year—and Voyager 1 still has some hydrazine left, although it’s running low. Once the hydrazine is depleted, the spacecraft will no longer be able to control its orientation, which means communication with Earth will cease.
The Voyager spacecraft have no engines for linear acceleration; instead, they follow the trajectory and speed gained from gravity assists during planetary flybys in the solar system.