In 2006, Pluto lost a bit of its planetary luster when the International Astronomical Union downgraded it to dwarf status. But the remote and mysterious orb still holds fascination for scientists at NASA and the Johns Hopkins Applied Physics Laboratory, whose New Horizons spacecraft will come within 8,000 miles of its surface on July 14.
Launched nine-and-a-half years ago from Cape Canaveral, New Horizons has traveled over 3 billion miles at 9 miles per second to reach the dwarf planet. In a two-hour flyby, it will take photographs and collect data with the aim of shedding light on the geography, atmosphere and geological history of Pluto. This unprecedented project, which cost $700 million, is the subject of "Mission Pluto," a special hosted by Jason Silva of "Brain Games" that will premiere July 14 on National Geographic Channel.
"Exploration is a deep, driving urge that propels us all. With the New Horizons mission, we open the door to an entirely new region of the solar system," says astronomer Marc Buie of the Southwest Research Institute and New Horizons co-investigator who used data form the Hubble Space Telescope to help plan the mission.
As the special explains, Pluto's elliptical 240-year orbit puts its distance from Earth between 3 and 5 billion miles. Since its discovery by astronomer Clyde Tombaugh in 1930, it was closest to us in 1989 and has gotten further away since, which is why this is the last chance in our lifetime to attempt the flyby.
Given the green light in 2001, New Horizons had to be built and launched in a tight four-year time frame, instead of the usual 10. It had to be light, with a reliable, very low wattage energy source. Instructions sent to it and information received take four and a half hours even at light speed, so Mission Control will literally be in the dark, waiting for the results to beam in. If it fails, they won't know until after the fact.
Buie and his colleagues have to hope they got their calculations right, and that the spacecraft doesn't encounter any hazards in the debris-filled Kuyper Belt that could send it off course. Obviously, there will be no second chances. Is he having sleepless nights? "I've never worried too much about this, since I've been too busy getting the work done," responds Buie, who began his personal "journey of exploration" to Pluto back in 1982.
"The exploration of the Pluto system is a tremendous challenge but one worth tackling," he emphasizes. "A lot of people have put their heart and soul into this mission and that gives us all confidence in its overall success. There is no question that these efforts are worth it. Even the attempt feeds our collective soul, but a success is even better."
An artist's illustration of Pluto. The New Horizons probe will provide more accurate measurements of the dwarf planet which will help scientists better understand Pluto's density and internal structure. (Photo: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute)
Pluto has been estimated at 1,400 miles in diameter, no bigger than Alaska, a figure New Horizons could confirm. "One measurement I'm keenly interested in is the true size of Pluto. Getting this one number will refine our knowledge of the bulk density of Pluto, giving us a better idea of its internal composition and structure," says Buie. "The size of Pluto is also critical to our understanding of the structure its atmosphere and how it affects the surface we see. I'm also very interested to see what types of geologic process act on Pluto and [its moon] Charon and how that relates to the striking patterns of albedo [the measure of light reflected by a surface]." This information will help us learn and understand more about our solar system, he adds.
To Buie, Pluto's reclassification doesn't diminish the importance of the New Horizons mission. "I do not believe Pluto has been demoted in any way. Recent discussions of the meaning of 'planet' or 'dwarf planet' have done little more than confuse people," he says. "I hope this issue will fade away once we see what sort of place Pluto really is. I've long known Pluto will be a fantastic place to study and I'm certain the mission results will confirm this."
If all goes according to plan, Buie will celebrate by "reflecting on what we've learned and taking satisfaction in a job well done by a fantastic team of people." His focus will continue to be on "the unknown. The small bodies in our solar system contain a wealth of information that we're only just beginning to unravel. My own particular interest lies in exploring the outer solar system, but I also have a great interest in learning more about objects that come near or even hit the Earth," he says.
Buie hopes that space exploration will continue to be a priority. "I grew up hearing comments about how we have to eliminate hunger, cure diseases, end war before we should be concerned with space exploration. I think that is a terribly limiting view of our abilities. I believe we have the capacity as a people to a great many things all at the same time," he says. "Space exploration and understanding how we came to be is what I do, and those skills do not come easy. I trust that there are others equally committed to the other large issues of our day."
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