After launching into space almost 50 years ago, NASA’s Voyager probes are reaching the end of their lives. The nuclear batteries onboard the two spacecraft are running out of juice, which means NASA is counting down the days until the death of Voyager 1 and Voyager 2 by slowly shutting off systems one by one.
NASA launched Voyager 1 and Voyager 2 back in 1977 and since then the two craft have traveled further into space than anything else man made. Almost 50 years spent traveling the cosmos has taken its toll on the two probes and Wired resorts that NASA is now preparing for the end.
When NASA launched the two craft into space, they were fitted with nuclear batteries that could generate power through decaying Plutonium-238 isotopes. Heat released by the decaying radioactive material is converted into energy to power the onboard systems, but Wired reports that this power is now running low:
But as time passes, the plutonium on board is depleted, and so the [radioisotope thermoelectric generators] produce less and less energy. The Voyagers are therefore slowly dying. Nuclear batteries have a maximum lifespan of 60 years.
In order to conserve the probes’ remaining energy, the mission team is gradually shutting down the various instruments on the probes that are still active. For example, in October, Voyager 2’s plasma science instrument—which measures electrically charged atoms passing the probe—was turned off; the same device on Voyager 1 was turned off in 2007 due to a malfunction. These instruments were used to study charged particles in the sun’s magnetic field, and it is precisely this detector in 2018 that determined that Voyager 2 had exited the heliosphere and become interstellar.
The reduced power onboard means that NASA has had to make some difficult decisions with regards to what sensors and instruments are still running on the two Voyager probes. After covering around 15 billion miles, just four instruments remain active onboard, including a magnetometer and other apparatus that can study the galactic environment.
Thankfully communications between Earth and the two probes are still up and running after NASA regained contact with Voyager 1 last month. Voyager 2 has also faced comms issues of its own that NASA had to work through last year, adds Futurism.
Now, the teams behind the two craft are targeting the 50th anniversary of Voyager 1 and Voyager 2 in 2027. Teams are hopeful that the two probes will last that long, and anything extra is a nice bonus, as Futurism reports:
Nonetheless, the team is still appreciative of a groundbreaking, decades-long mission that’s even managed to escape the heliopause, the outer boundary of the Sun’s heliosphere.
“I think we’re all happy and relieved that the Voyager probes have both operated long enough to make it past this milestone,” said Voyager project manager Suzanne Dodd in a November statement. “This is what we’ve all been waiting for. Now we’re looking forward to what we’ll be able to learn from having both probes outside the heliopause.”
Once power goes out, the two craft will continue on their current trajectory until they hit something, which means there’s just no knowing quite how far the famed gold disc strapped to each probe will make it into the cosmos.