Published in The Patriot Ledger July 25, 2015
I called it “poor little Pluto” in an earlier column, but Pluto was very big in the news last week when NASA’s New Horizons spacecraft flew by it after traveling more than 9 years and more than 3 billion miles through space. It was a tremendous success for the New Horizons team led by Principal Investigator Alan Stern and Mission Operations Manager Alice Bowman, known to the team as MOM.
Other NASA spacecraft flew by our nearest-neighbor planets Mars and Venus in the 1960s, by Mercury, Jupiter, and Saturn in the 1970s, and by Uranus and Neptune in the 1980s. When Voyager 2 flew by Neptune in 1989, young graduate student Alan Stern was taking a course on planetary exploration at Cal Tech, and became obsessed with getting a mission together for Pluto, then recognized as the ninth planet.
For over a decade, Stern and others promoted a variety of plans for a mission to Pluto, but NASA’s budgetary limitations continually frustrated the efforts. NASA finally gave in and approved the New Horizons proposal in 2001. Led by Alan Stern and their MOM, the team designed and built a very sophisticated thousand-pound spacecraft, about the size of a piano. It was launched from Cape Canaveral in January 2006, and finally flew by Pluto last Tuesday, getting much more detailed pictures of Pluto’s surface than had been available before. Data were also gathered on the chemical composition of Pluto and its atmosphere, data that will take scientists years to analyze. A remarkable achievement, finally achieved 26 years after Alan Stern first set his heart and mind on a mission to Pluto.
Stern has been involved with numerous other NASA space missions, but a mission to Pluto remained his abiding interest. Imagine his feelings when, seven months after the launch of New Horizons, the International Astronomical Union voted for a new definition of the word “planet,” one that removed Pluto from the list of planets in the solar system. His mission was no longer going to the ninth planet. It was going to what was now known as a dwarf planet. Quite a comedown.
Pluto is indeed smaller than the eight planets formally recognized by the International Astronomical Union, and is even smaller than the Earth’s moon. But Stern continues to refer to Pluto as the ninth planet, and considers last week’s flyby to be the completion of the initial exploration of the solar system. After its discovery in 1930, it was considered to be the outer edge of the solar system. However, later many other objects were found orbiting the sun in Pluto’s neighborhood and well beyond, a region now called the Kuiper Belt.
Neil deGrasse Tyson, director of New York’s Hayden Planetarium and inheritor of Carl Sagan’s television series Cosmos, continues to support Pluto’s demotion from full planetary status. In a recent tweet showing New Horizon’s beautiful picture of Pluto, he wrote, “Dear Pluto, Lookin’ good. But you’re still a Dwarf Planet – get over it. Love, Neil deGrasse Tyson.” But Tyson doesn’t demean the accomplishment of the New Horizons team, describing it as an important first close look at a Kuiper-Belt object.
Back in 1991, the US Postal Service issued a set of postage stamps celebrating NASA’s achievements in planetary exploration, with one stamp for each of then-recognized nine planets. Pictures of eight of the planets were accompanied by pictures of NASA spacecraft that had visited them. The Pluto stamp instead simply said, NOT YET EXPLORED. One of these stamps was carried to Pluto aboard New Horizons, and at a celebration of the flyby, Alan Stern proudly held up a large version of the stamp with NOT and YET crossed out.
Planet or dwarf planet, Pluto has now been explored. Early discoveries include mountains of ice on Pluto as tall as the Rockies and a chasm on Pluto’s moon Charon longer and deeper than the Grand Canyon. And there’s much, much more to come.