After lying dormant for more than three decades, the backup thrusters on the Voyager 1 spacecraft were fired up again on Tuesday (November 28) as part of a test to verify if they are still operational. Not only did they perform admirably, NASA informs, but they will also be assigned a new important job that will extend the spacecraft’s life by up to three years.
The Voyager 1 spacecraft operates on two different kinds of thrusters: “attitude control thrusters” and “trajectory correction maneuver,” or TCM. The first type of thrusters is currently used to help orient the spacecraft in the optimal position so that its antenna can communicate with Earth. The latter, a set of four backup thrusters located at the back of the spacecraft, helped maneuver Voyager 1 during its last planetary flyby 37 years ago.
Considering the TCM thrusters hadn’t been used in such a long time, the exceptional outcome of last week’s test is truly a cause for celebration. The last time Voyager 1 needed to rely on its TCM thrusters was on November 8, 1980, when the spacecraft reached Saturn and began its mission to conduct close-up studies of the planet and its rings.
Now, almost four decades later, Voyager’s TCM thrusters are still in great shape and ready to get back to work, the test revealed. Originally designed to burn continuously for relatively long stretches of time, the backup thrusters were now assessed for attitude control, and passed the test with flying colors.
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This is the first time the TCM thrusters are used as attitude control thrusters, NASA explains in a news release. During the test, the team fired the four backup thrusters at 10-millisecond pulses — quite a change from the TCM’s standard task.
Nevertheless, the backup thrusters were able to rotate Voyager 1 even when fired in short bursts, and successfully oriented the spacecraft to help it communicate with our planet.
To ensure Voyager’s TCM thrusters could be fired up safely after their 37-year-long slumber, the spacecraft’s flight team had to comb through decades-old data and analyze software “coded in an outdated assembler language,” NASA shows.
After firing up the TCM thrusters on Tuesday, the team had to wait 19 hours and 35 minutes for the results to travel through space, and finally received confirmation on Wednesday that everything was in top shape.
“The Voyager team got more excited each time with each milestone in the thruster test,” said Todd Barber, propulsion engineer at NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, California.
“The mood was one of relief, joy and incredulity after witnessing these well-rested thrusters pick up the baton as if no time had passed at all,” he added.
Since the TCM thrusters performed so well in attitude control, NASA plans to instate them in the new job come January. The decision came as an ingenious solution to the problem Voyager 1 is currently facing with its long-used attitude control thrusters, which have started to degrade since 2014.
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Thus, the Voyager backup thrusters will take on the role of attitude control starting next year, thereby prolonging the time Voyager 1 will be spending in space.
According to Suzanne Dodd, project manager for Voyager at JPL, the TCM thrusters will “extend the life of the Voyager 1 spacecraft by two to three years.”
In order to make the switch, the spacecraft needs to turn on a heater for each of the four TCM thrusters, which will require the use of extra power. This means the backup thrusters will only be able to function as attitude control thrusters until the power supply gets too low.
Built to last five years, Voyager 1 was launched on September 5, 1977, and is still functioning 40 years later as “NASA’s farthest and fastest spacecraft.” In August 2012, Voyager 1 became the first human-made object ever to enter interstellar space, Space.com notes. Its twin sister, Voyager 2, is expected to join it there within the next few years.
Although the attitude control thrusters on Voyager 2 are in better shape, the mission team plans to conduct a similar test on the spacecraft’s TCM thrusters as well.