Chasing New Horizons: Inside the Epic First Mission to Pluto
© 2019 Alan Stearns & David Grinspoon
For most of my life, and I’ll warrant for most of yours, Pluto was the Great Unknown in the solar system. Take any volume on astronomy from the 1990s or early 2000s, and you would find no shortage of pictures or data on everything from Mercury to Neptune, including many moons. Pluto, though, was an enigma; the best one might find was a photo of a hazy orb, and similarly nebulous guesses at its surface and atmosphere. Unlike the gas giants who were visited by the Voyager Program in the 1970s Pluto was never visited by probes from Earth – until 2015, when a mission launched in 2006 and planned for decades resulted in the first flyby of the coldest of planets. Chasing New Horizons is a history of that project, which had to surmount both technical and political challenges, which incorporates the complete history of Pluto from its discovery in the 1930s onward. It’s a stirring story of hope, creative thinking, and sheer cussed determination that have resulted in a boon of wonder and information.
Pluto was the last planet of the traditional nine to be discovered, and it was done so by a young student named Clyde Tombaugh, at the Lowell Observatory in Flagstaff Arizona. Lowell himself had predicted the existence of an object in that area, but it was Tombaugh’s incredible patience and careful deliberation that exposed that tiny white spot so far away from us and everything else. It remained a complete unknown even into the late seventies, when its moon Charon was spotted and the Voyager program began its sweep of the great giants. Although many young astronomers began thinking about Pluto as the next obvious place to study, finding the resources to make that happen was a challenge. Chasing New Horizons documents multiple missions and approaches in the late eighties and nineties that were in various stages of planning and development when the prospective funding for them disappeared; the most disappointing of these would have been a mid-1990s collaboration with Russia, in which an American satellite would be launched from a Russian rocket, sharing credit and greatly reducing the costs of a Pluto flyby from the American end. Russia wanted some marginal financial compensation for the use of the rocket, but US laws at the time made that impossible. In the early 2000s, though, continued planning passes at a Pluto project resulted in a mission that would both excite the scientists and pass muster with NASA’s accountants, and New Horizons lifted off just in time to be informed that it would be visiting not the smallest planet, but the biggest of the Kuiper-Belt Objects. Uh, thanks? (The authors very much disapproved of the IAU’s decision and called it names.) The mission of New Horizons’ human team wasn’t over then, though: for the next decade they had to carefully monitor the probe on its way, responding to technical hiccoughs by improvising on the fly and finding ways to shepherd resources carefully until the probe could arrive and begin taking its surveys. Then, of course, it stopped responding to NASA….but for that story you’ll want to read Chasing for yourself!
How I Killed Pluto and Why It Had it Coming, Mike Brown.
The Pluto Files: The Rise and Fall of America’s Favorite Planet, Neil deGrasse Tyson
“Atop Mars Hill”, a visit to the Percival Lowell observatory