NASA’s Voyager 2 just became the second human-made object to boldly go beyond the heliosphere and into interstellar space, which blew everyone’s mind a little, but what will this intrepid probe be up to next?
Voyager 1 might have beat it by five years — but its twin has something on board that it doesn’t. While both Voyagers were equipped with an onboard Plasma Science Experiment (PLS), Voyager 1’s stopped working in 1980. Voyager 2 still has an active PLS that was able to pick up the plasma escaping from the sun while it was still floating around in the heliosphere, that bubble around the planets in our solar system created by solar wind.
The PLS measures aspects of the solar wind using the electrical current of that plasma. When it was no longer transmitting any more solar wind data, scientists were positive it had gone into the great beyond.
Voyager 2 also has a trio of other instruments that have been active since 1977 even though the probe’s life expectancy was only five years. Its cosmic ray subsystem, low energy charged particle system and magnetometer have beamed back additional evidence that it has ventured past the heliopause, and will continue to give those of us back on Earth an idea of what space is like outside the bubble.
“Voyager has a very special place for us in our heliophysics fleet,” said director of NASA’s Heliophysics Division Nicola Fox. “Our studies start at the Sun and extend out to everything the solar wind touches. To have the Voyagers sending back information about the edge of the Sun’s influence gives us an unprecedented glimpse of truly uncharted territory.”
They may also be discovering things for another several years. As radioactive material contained in a radioisotope thermal generator (RTG), it releases heat that powers the Voyager probes. This isn’t a sustainable source of fuel. Because the RTG power output loses 4 watts each year, scientists on the Voyager team have had to make some difficult decisions regarding which parts of the probes to shut off to maximize power and potential science return.
Voyager 2 took off 41 years ago. NASA hopes those 41 years will stretch to at least 50.
Both Voyagers will still be seeking the edge of the solar system long after their instruments have gone dark. Try 300 years to reach the inner edge of the mysterious Oort Cloud and 30,000 to finally leave it (and the solar system) behind.