And they are still making news, as researchers announced last month Voyager 1 had outrun the solar wind, the first man-made object to reach the threshold of interstellar space, The Baltimore Sun reported Monday.
It's a performance that impresses even Stamatios "Tom" Krimigis of the Johns Hopkins University's Applied Physics Lab, one of just two remaining principal investigators of the mission's original 11 still on the job 40 years after NASA approved the Voyager missions.
"Needless to say, none of us expected it was going to be operating for so long," Krimigis, 72, said. "We were all praying to get to Neptune [in 1989]. But after that? Who thought we could be with this 33 years [after launch]?"
Five experiments on each Voyager are still funded and seven of them are still delivering data. Problems do occur, but they can be fixed by radioed instructions -- instructions that take 12 hours to reach the unmanned craft.
"I suspect it's going to outlast me," said Krimigis.
2014: The Year in Music [PHOTOS]