The New Horizons mission to Pluto has excited space enthusiasts around the world, promising to shed light on the outer reaches of our solar system. Mike O'Sullivan reports that no one is paying closer attention than members of the Planetary Society, a space advocacy group based in Pasadena, California.
There were two days of delays because of the weather and electrical problems, but Thursday, all system were go at Cape Canaveral, Florida, for the mission to Pluto.
The Planetary Society's executive director Louis Friedman says members of the group are monitoring this mission as concerned parents would. The private organization of space enthusiasts, from scientists to students, is based in California and has members all over the world.
"NASA actually tried to cancel this mission three times, and we went to Congress, and we lobbied for it," he said. "We got our members involved. Members wrote to Congress. We petitioned the administration and Congress three separate times when it was going to be canceled, and we won each time. So in some respects, I regard this as the people's mission."
To draw attention to the mission, the Planetary Society sponsored a debate over whether Pluto is really a planet. Most people consider it the ninth planet of our solar system, but the space scientist says, some people disagree.
"Well, it's a great debate," he said. "I mean, some people would say there are not even nine planets. There are only eight, and these other things that are being discovered are another class of objects."
The other objects are rock and ice bodies in what is called the Kuiper Belt, which extends from Uranus for billions of kilometers to the outer edges of the solar system.
People around the United States weighed in on the debate. One from Washington State asked why Pluto is a planet, but Ceres is not. Ceres is an asteroid 1000 kilometers wide, nearly half the diameter of Pluto, and it circles the sun between the orbits of Mars and Jupiter. One respondent from Texas hopes Pluto is a planet, because too many other things that he learned in school are no longer true.
Louis Friedman says the debate is mostly tongue-in-cheek. Calling Pluto a planet or calling it something else is really just a question of categories. We know of at least one planet-sized object beyond the orbit of Pluto, and he says this mission will shed light on the nature of these objects in the outer solar system.
"Basically, we're putting together a giant jigsaw puzzle," he noted. "And the answer to the jigsaw puzzle, the result of it, is called solar system evolution. What has happened? How did the solar system get formed? How did planets get formed? What makes a terrestrial planet? What's the water inventory in the solar system? "
He says this knowledge will help us understand the growing list of planets that scientists know are orbiting other stars. Friedman says the number is rising, and is now past 100.
The Planetary Society is monitoring this mission for another reason. When the New Horizons spacecraft reaches Pluto in 2015, it will send a signal to earth to open a digital archive showing the changes here on earth in the nine years of the mission. He says people have sent digital files with everything from scientific data to pictures of their grandchildren.
"There will be remarkable technological changes, maybe in genetic engineering, maybe in medicine, maybe in space travel," he explained.
He adds that because of this mission, there should also be changes in our understanding of the solar system.