By Hammer - 5/18/2025
Imagine trying to fix a car that’s farther away than any place you could ever travel—so far, in fact, that your instructions take almost a full day just to reach it. That’s the challenge engineers at NASA’s Jet Propulsion Laboratory (JPL) in California faced this year as they worked to revive a critical part of the Voyager 1 spacecraft: a set of thrusters that hadn’t worked for over 20 years.
Voyager 1 is a legendary spacecraft launched in 1977, now speeding through interstellar space at 35,000 miles per hour—way beyond the edge of our solar system. Along with its twin, Voyager 2, it has sent back amazing discoveries about our planets, and is now the most distant human-made object in the universe, nearly 15 billion miles from Earth.
Spacecraft like Voyager need to keep their antennas pointed at Earth so we can talk to them and receive their scientific data. To do this, Voyager uses small rocket engines called thrusters. These thrusters make tiny adjustments, or “rolls,” keeping the spacecraft’s antenna aimed precisely.
Voyager 1 actually has two sets of these roll thrusters: a primary set and a backup set. But the primary set stopped working in 2004 because two tiny heaters inside them failed. The team switched to the backup thrusters, which have worked ever since. But after so many years, these backup thrusters are now at risk of clogging up—a problem that could leave the spacecraft unable to point at Earth and communicate at all.
The situation became even more urgent because the only giant radio antenna on Earth powerful enough to send commands to Voyager 1—called Deep Space Station 43 in Australia—was scheduled to go offline for major upgrades from May 2025 until February 2026. If engineers couldn’t fix the primary thrusters before then, they might lose the ability to help Voyager 1 if anything went wrong.
The JPL team decided to take a risk: Could they somehow bring the “dead” primary thrusters back to life? Their detective work suggested that an electrical switch, which controlled the heaters, might have been accidentally set wrong decades ago. If they could send commands to flip that switch back, the heaters (and hopefully the thrusters) might work again.
But there was a catch. If they got it wrong, firing the cold thrusters without the heaters could cause a tiny explosion—enough to damage the spacecraft. So everything had to be timed and targeted perfectly.
On March 20, 2025, the team sent a set of commands—knowing it would take over 23 hours for their signal to reach Voyager 1. Then they waited.
When the data came back, they saw the temperature of the thruster heaters rising. It had worked! For the first time in over 20 years, the primary roll thrusters were alive again.
“It was such a glorious moment. Team morale was very high that day,” said Todd Barber, the mission’s propulsion lead at JPL.
Pushing the Limits: Voyager 1 was only expected to last five years. It’s still exploring 47 years later, thanks to the creativity and determination of its team.
Real-World Problem Solving: The fix combined deep technical know-how with some serious detective work and courage to try something risky.
Legacy and Inspiration: As Voyager 1 and 2 continue to travel through interstellar space, they inspire new generations of scientists and engineers to dream big and solve problems that seem impossible.
Voyager 1 distance from Earth: ~15 billion miles (25 billion kilometers)
Voyager 2 distance from Earth: ~13 billion miles (21 billion kilometers)
Speed: ~35,000 mph (56,000 kph)
Launched: 1977
First to enter interstellar space
Carrying: The famous “Golden Record,” a message for any alien life that might one day find it
Check out NASA’s official Voyager page for updates, mission history, and amazing discoveries.
Fun Fact:
A signal from Voyager 1 takes more than 23 hours to reach Earth—so every time NASA talks to the spacecraft, they’re really talking to the past!