In 1977, NASA launched two spacecraft, Voyager 1 and 2, on a grand tour of the solar system and into the mysteries of interstellar space. Attached to each of these probes is a golden phonograph record containing a message for any extraterrestrial intelligence that might encounter it, perhaps billions of years from now. (I co-produced the first terrestrial vinyl release of the Voyager Golden Record.) These two astonishing spacecraft far exceeded their life expectancy and have continued to transmit valuable scientific data back home. Now though, it's time for NASA to thoughtfully begin powering down each system in a very thoughtful and process order to hopefully eke out a few more years of communication with Earth. If all goes as planned, we'll still hear from them until about 2030. From Scientific American:
"We're at 44 and a half years," says Ralph McNutt, a physicist at the Johns Hopkins University Applied Physics Laboratory (APL), who has devoted much of his career to the Voyagers. "So we've done 10 times the warranty on the darn things."[…]
Voyager 2 now has five remaining functioning instruments, and Voyager 1 has four. All are powered by a device that converts heat from the radioactive decay of plutonium into electricity. But with the power output decreasing by about four watts a year, NASA has been forced into triage mode. Two years ago the mission's engineers turned off the heater for the cosmic-ray detector, which had been crucial in determining the heliopause transit [into interstellar space].
Everyone expected the instrument to die.
"The temperature dropped like 60 or 70 degrees C, well outside any tested operating limits," [JPOL planetary scientist and original Voyage team member Linda] Spilker says, "and the instrument kept working. It was incredible."
The last two Voyager instruments to turn off will probably be a magnetometer and the plasma science instrument. They are contained in the body of the spacecraft, where they are warmed by heat emitted from computers. The other instruments are suspended on a 43-foot-long fiberglass boom. "And so when you turn the heaters off," [Voyager project manage Suzanne] Dodd says, "those instruments get very, very cold."
