Engineers at NASA's Jet Propulsion Laboratory have preserved the power reserves of the record-breaking Voyager 1 and 2 space probes nearly 50 years after their launch to extend their lifespan.
In 1977, NASA began launching probes that used a decaying radioisotope power system that generated electricity from the heat of decaying plutonium.
Each probe loses about 4 watts of power each year, but NASA has extended their missions by turning off some of their instruments to conserve the remaining energy.
“Since their launch, the Voyagers have become the stars of deep space,” said Voyager project manager Suzanne Dodd. “We want to keep that going for as long as possible.”
Dodd said the probes' power supplies are running low and will only last for several months before they are shut down and end their missions unless steps are taken to reduce their power consumption.
Each spacecraft is equipped with identical sets of 10 scientific instruments, some of which are designed to collect data during flybys of planets.
The flyby instruments were turned off after each probe completed its exploration missions to the solar system's gas giants.
Other instruments remained active while studying the solar system's heliosphere, which NASA describes as “a bubble of solar wind and magnetic fields created by the Sun.”
The remaining active instruments will also help the probe explore interstellar space, the region beyond the heliosphere.
The Voyager 1 and Voyager 2 probes reached the edge of the heliosphere and began entering interstellar space in 2012 and 2018, respectively.
These are the only man-made spacecraft that have operated in interstellar space.
In October, NASA engineers turned off an instrument measuring the amount and direction of electron-charged atoms known as plasma on Voyager 2.
The same instrument was turned off on Voyager 1 several years ago due to deteriorating performance.
Last week, mission engineers turned off the cosmic ray subsystem on board Voyager 1, which was used to study cosmic rays, including protons, by measuring their energy and flux.
The cosmic ray subsystem used three telescopes to carry out its mission and determine the moment and location when the probe left the heliosphere.
Mission engineers are also preparing to turn off Voyager 2's low-energy particle instrument, which measures ions, electrons and cosmic rays emanating from the solar system and galaxy.
“The Voyager spacecraft has greatly exceeded its original goals for exploring the outer planets,” said Patrick Cohen, NASA's Voyager program scientist.
“Every bit of additional data we've collected since then is not only a valuable scientific resource for heliophysics, but also a testament to the remarkable engineering that went into building the Voyagers, starting nearly 50 years ago and continuing to this day.”
NASA engineers expect the probes to operate for another year before each one needs to turn off an additional system to save power and extend their missions.
The power conservation plan for the Voyager 1 and 2 probes should allow them to remain active until the 2030s.
Each probe has been exposed to deep space conditions for 47 years, which could shorten their lifespans.
According to NASA, each of the probes is the most distant human-made object ever created: Voyager 1 has flown more than 15 billion miles from Earth, and Voyager 2 has flown more than 13 billion miles.
“Every minute of every day, the Voyagers are exploring where no spacecraft has gone before,” said Linda Spilker, Voyager project scientist.
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