Voyager 1 fired thrusters it has decades to use

NASA engineers successfully fired a set of thrusters that the 47-year-old Voyager 1 spacecraft hasn't used in decades.

The aged but still functional Voyager 1 on their journey into the unknown creates problems unprecedented for NASA engineers. Their main problem is that the spaceship is always in such a position that it can send information to Earth and can also receive commands from it.

Voyager 1 launched into space on September 5, 1977 and is currently about 24 billion miles away. Certainly in 1977 no one expected it to still work today.

Currently the farthest spacecraft from Earth, Voyager 1 operates beyond the heliosphere, the sun's bubble of magnetic fields and particles that extends far beyond Pluto's orbit, where its instruments take samples from interstellar space.

As a result of its extremely long mission, Voyager 1 is experiencing problems as its components age in the frozen space outside our solar system.

When a problem arises, engineers at NASA's Jet Propulsion Laboratory in Pasadena, California, have to get creative while worrying about how the spacecraft will react to any changes.

Engineers have found a problem as the fuel line inside one of Voyager 1's thrusters became clogged. The result was that the thrusters could not generate enough force to keep the spacecraft stable and above all oriented in a way that it could communicate with Earth.

Over the years of use, engineers have discovered that the fuel line inside the thrusters can become clogged with silicon dioxide, a byproduct of the aging of the fuel tank's rubber diaphragm.

To feed the promoters, the liquid hydrazine it turns into a gas and is released in about 40 short puffs a day to keep Voyager 1 properly oriented.

it's not the first time that Voyager 1 needs to switch to another set of thrusters in recent decades. Fortunately, the spacecraft has three sets of thrusters: two sets of thrusters and one set dedicated to orbit correction maneuvers.

The team realized they would have to send commands to the spacecraft to switch to another set of thrusters, but the fix wouldn't be as simple as it sounds.

In 2002, the team had already instructed Voyager 1 to switch to the second set of thrusters when the first set showed signs of clogging. In 2018, the engineers switched back to the thrust-correction set when the second set also appeared to be clogged.

But when the team recently checked the condition of Voyager's orbit-correction thrusters, they were even more clogged than the previous two sets of thrusters.

According to NASA, when the team switched Voyager to its orbit-correction thrusters in 2018, the tube opening was 0,25 millimeters wide. But now, the blockage has reduced it to 0,035 millimeters, half the width of a human hair.

So as Voyager 1 and its twin, Voyager 2, aged, the mission team slowly turned off non-essential systems on both spacecraft to save energy, including heating systems.

As a result, the components on Voyager 1 are colder now, and the team knew they couldn't just send a command to Voyager 1 to switch directly to one of the constant-propulsion thrusters without first doing something to warm them up.

However, Voyager 1 does not have enough power to turn any heating back on without turning off something else, such as its valuable science instruments as there is a fear that if they go out they may not come back on.

After trying various plans of action on paper, the team realized they could shut down one of the spacecraft's main heaters for about an hour, which would allow engineers to turn on the thrusters' heaters and launch it safely.

This plan worked well until August 27, and Voyager 1 again used its original set of thrusters to stay in contact with Earth.

The team has taken steps to use as few thrusters as possible and expects to still use the original set for another two to three years, said Todd Barber, Voyager's propulsion engineer.

Once the starship has exhausted this set of thrusters, the remaining option is the other, already blocked, set of thrusters.