I just read that NASA has retired Ulysses, one of its longest-serving space probes. Ulysses was launched in 1990 to study the polar regions of the Sun, and was also able to make observations of Jupiter and study the tails of comets Hyakutake, McNaught-Hartley, and McNaught. The deactivation of the probe marks the end of the longest-running active NASA mission. Ulysses transmitted data to Earth for seventeen years and seven months, traveling 8.6 billion kilometers in that time.
This is the sort of story I love, and not just because I’m a space nut. It’s a great show of the middle finger to those anti-NASA types who love to piss and moan about how the space program is a waste of their tax dollars. They jump all over failures like the Mars Surveyor mission ten years ago, but conveniently ignore programs like Ulysses, which exceed all expectations. Ulysses was built for a five year mission. Its mission lasted over three times that long. In that time the probe made the first extended study of solar wind, measured cosmic rays entering the solar system from outside the heliosphere, and sampled isotopes of interstellar helium. It has expanded our understanding of our own cosmic neighborhood, and of the universe at-large, provided astronomers and cosmologists with a better understanding of how the cosmos was born, and how it may end. Ulysses was an emphatic success.
And it wasn’t the only one. NASA’s Pioneer 10 and Pioneer 11 probes were the first to study the outer planets and are currently on trajectories that will carry them out of our solar system. They were launched in 1972 and ’73, respectively, and remained in contact with Earth thirty years later — Pioneer 10 last transmitted telemetry in 2002, and its final signal was received in 2003.
The Voyager probes are now the fastest and farthest-away man-made objects ever launched. Voyager 1 is over 9.4 billion miles from the Sun, making it the most distant known object (natural or man-made) in the solar system. They were launched in 1977, designed to study Jupiter and Saturn. Both Voyagers continue to operate and return data to Earth, and have sufficient power to remain active until 2020. Even after their functions cease, the trajectories of Voyager 1 and Voyager 2 will continue to carry them out into interstellar space.
The Pioneers and Voyagers, along with Ulysses and an impressive list of other unmanned space probes, validate every last cent spent to fund NASA in the last half-century. They have served their purposes and then some, returning important scientific information from well past their original expiration dates. And they’ve done more than that. They’ve testified to the potential of the human mind, of our ability as a species to do extraordinary things. Pause a moment and think about this: there are objects built by human hands — functioning machines — that have traveled farther away from us than any planet, asteroid, or comet orbiting the Sun. If that doesn’t tell you something about human potential, if it doesn’t fill you with awe and pride in the good we are capable of doing, then there’s not much else I can tell you.
I happen to believe that the exploration of the universe requires no justification. “Because we can” is reason enough to do it. Knowledge about our Sun, our solar system, the universe is its own reward. I’m happy to absorb the occasional failures like Mars Surveyor in exchange for the amazing and stirring triumphs of the Pioneers, the Voyagers, and Ulysses. Well done.