John Salmon mentions the Voyager spacecraft, which were launched 40 years ago in August and September. These, along with Pioneer 10 and 11, launched five and four years earlier, are four of the five spacecraft leaving the Solar System, and are the most distant man-made objects at this time. NASA is planning a quiet little celebration Tuesday.
For the future of the Pioneer and Voyager probes, see the fifth and sixth episodes of Jinrui wa Suitai Shimashita, which reveal the true reason for the Pioneer anomaly.
Thanks for the mention. But not the article about the Pioneer anomaly (!). Another article bookmarked for future reading. I’ve got about fifty of them!