Science

Firing Voyager's Thrusters After 37 Years

Firing Voyager's Thrusters After 37 Years

Voyager 1 and Voyager 2 were launched 16 days apart in 1977.

Stone was 36 years old when he first started working at the Jet Propulsion Laboratory, where both Voyagers were built. With this example before them, NASA laid a more ambitious message aboard Voyager 1 and 2, a kind of time capsule, meant to relate a story of our world to aliens.

The spacecraft, which has been flying for 40 years, relies on small thruster devices to move itself so it can communicate with Earth. NASA plans to switch to the backup thrusters in January and when there's no longer enough power for those, switch back to the main ones.

More detail on the TCM thrusters can be found here. Keeping a communication link open to a space probe that's now over 13 billion miles away from Earth isn't easy, and it requires precise adjustments to the spacecraft's orientation. The team was delighted when the results of their test were resoundingly positive. Back then, the TCM thrusters were utilized in a more constant firing mode; they had never been used in the brief explosions necessary to orient the spacecraft. But because Voyager 1's last planetary encounter was Saturn, the Voyager team hadn't needed to use the TCM thrusters since November 8, 1980.

All of Voyager's thrusters were developed by Aerojet Rocketdyne.

Last week, experts learned that the TCM thrusters worked perfectly fine. Voyager 1 is farther from Earth than Voyager 2, due to differences in their missions and trajectories, at an estimated 141 AU from Earth (1 AU is the distance between Earth and the sun).

"The Voyager flight team dug up decades-old data and examined the software that was coded in an outdated assembler language, to make sure we could safely test the thrusters", Chris Jones said.

"The Voyager team got more excited each time with each milestone in the thruster test", said Todd Barber, a propulsion engineer at NASA's Jet Propulsion Laboratory (JPL). One interesting aspect of this was that the team waiting to hear a response on the thrusters had to wait 19 hours and 35 minutes for it to reach a Deep Space Network antenna located in California.

The last time these engines were run in 1980.