We are sandwiched in the middle of two major space anniversaries. Next year there will doubtless be tons of material commemorating the fiftieth anniversary of…. (I’ll let you fill in the rest.) But last year was also a major anniversary in spaceflight. Do you know what it was of? Forty years ago NASA launched two Voyager probe. Here is a New York Times article on Voyager and its history. They made flybys of Jupiter, Saturn, Uranus, and Neptune. Today the two Voyager probes are 10 and 13 billion miles away. What is perhaps more amazing is that a team of engineers has been working on Voyager for 30+ years. On the one hand, the little attention that we give to Voyager perhaps vindicates the ideas of Kennedy and others versus Jerome Wiesner that people would only be interested in a flight that carried humans. On the other hand, one could easily argue that this is a far greater technical and scientific accomplishment than Apollo, as significant as that was. The French journal Le Monde has a detailed article on Voyager. It’s in French (doh!), but it has some nice graphics that can be understood without knowing French. They try to give a sense of the distance Voyager has traveled (if each 1,000,000 km were represented by a pixel.)