NASA engineers have announced plans to disable a pair of science instruments on the iconic Voyager probes, hoping to extend the science missions of the two farthest human-made objects from Earth.
On Wednesday, the American space agency revealed that Voyager 1’s cosmic ray subsystem experiment was shut off on February 25. Voyager 2’s low-energy charged particle instrument will also be deactivated on March 24.
Voyager 1’s cosmic ray subsystem, which is comprised of three telescopes that collect information about cosmic rays and protons the probe encounters, allowed NASA engineers to monitor the probe’s journey on its way out of the solar system’s heliosphere.
Similarly, Voyager 2’s low-energy charged particle instrument, consisting of subsystems monitoring particles and magnetospheric phenomena, was used to measure any ions, electrons, or cosmic rays the probe encountered.
According to Voyager mission engineers at NASA’s Jet Propulsion Laboratory in Southern California, the three remaining science instruments aboard each spacecraft will maintain normal operations.
The decision to shut off the two long-running instruments was made in an effort to extend the lifespan of each spacecraft, as their power systems continue to dwindle after several decades of operation.
A Space Odyssey Decades in the Making
If the Voyager spacecraft can maintain operations until August 2027, they will have been in service to NASA for half a century. That’s a remarkable feat, given that the two space probes were only designed to operate for five years.
Based on current estimates, both Voyager spacecraft could potentially remain within the range of NASA’s Deep Space Network until around 2036, should their power systems succeed at delivering energy to their existing science instruments for that long.
However, power must also be allocated to transmitting signals back to Earth. At a current power loss of about 4 watts yearly, the likelihood that the spacecraft can successfully dispatch data for such an extended period seems improbable.
Both Voyagers use a radioisotope power system that produces electricity from heat generated by decaying plutonium they carry. Even while the prospect of extending their mission for much longer will continue to diminish in the years ahead, these remarkable space probes have already broken records with their duration and the incredible distance they have traveled.
“The Voyagers have been deep space rock stars since launch, and we want to keep it that way as long as possible,” said Suzanne Dodd, Voyager project manager at JPL.
Dodd says that with electrical power running into the red on the Voyager spacecraft, she expects they would each only last for a few more months unless some of their science instrumentation is powered down.
Several other instruments in the original array of 10 each probe was fitted with have been turned off over the years, including those designed solely for collecting data as they passed close to planets, including the gas giants in our solar system.
Beyond their planetary visits, instruments that allowed ongoing study of the solar system’s heliosphere remained operational until their journey brought them beyond its barriers. Voyager 1 made its way to the heliosphere’s edge in 2012, with Voyager 2 following suit six years later.
Late last year, Voyager 2’s plasma science instrument was also disabled, primarily because it had only collected a small amount of data due to the spacecraft’s directional orientation. Voyager 1’s plasma instrument had already been deactivated years earlier after demonstrating poor performance.
Voyager’s Final Frontier
The Voyager team’s engineers have taken great care to avoid turning off the spacecraft’s science instruments until absolutely necessary to ensure power reduction. However, within one year, they expect to need to deactivate additional instruments on board each spacecraft.
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Voyager 1 will likely have its low-energy charged particle instrument shut down sometime early next year, while Voyager 2’s cosmic ray subsystem is scheduled to be deactivated in early 2026.
The Voyager team hopes that such measures will help ensure the probes have enough power to carry them into the 2030s, enabling them to continue dispatching science data for years to come, so long as both spacecraft can communicate via the Deep Space Network.
Patrick Koehn, Voyager program scientist at NASA Headquarters in Washington, said the two iconic NASA spacecraft have already “far surpassed their original mission to study the outer planets,” adding that “Every bit of additional data we have gathered since then is not only valuable bonus science for heliophysics but also a testament to the exemplary engineering that has gone into the Voyagers — starting nearly 50 years ago and continuing to this day.”
Linda Spilker, a Voyager project scientist at the mission’s headquarters at JPL, said that at this point “every day could be our last.”
“But that day could also bring another interstellar revelation,” Spilker adds.
“So, we’re pulling out all the stops, doing what we can to make sure Voyagers 1 and 2 continue their trailblazing for the maximum time possible,” she said.
Micah Hanks is the Editor-in-Chief and Co-Founder of The Debrief. He can be reached by email atmicah@thedebrief.org. Follow his work atmicahhanks.comand on X:@MicahHanks.