The first spacecraft mission to the last of the original nine planets in our solar system is schedule for launch on Tuesday, January 17, 2006. New Horizons will begin its journey as the fastest spacecraft ever launched from the Earth. The speed is necessary to reach Pluto and its three known moons in just a little over nine years.
Pluto lies in a region of our solar system known as the Kuiper Belt, a disk-shaped band around the Sun thought to consist of tens of thousands or more small icy bodies. The existence of the Kuiper Belt has been confirmed by the discovery since 1992 of several objects nearly the size of Pluto. Last year, astronomers announced the discovery of a a Kuiper Belt object code named “Xena” that is larger than Pluto. Soon after came announcements about two new moons found orbiting Pluto and a moon found orbiting the tenth planet.
New Horizons will fly by Pluto, its largest moon Charon, and its two smaller moons in July 2015. All instruments on board the spacecraft will have to work quickly to explore the Plutonian system because close approach will last only 24 hours. Once it has passed Pluto, New Horizons will target other Kuiper Belt objects between 2016 and 2020.
Since the discovery of Xena, scientists have been debating just what a planet is, a debate that will have to be resolved before the body can be officially named. If scientists agree that Pluto is just another member of the Kuiper Belt, it may lose its status as a planet and the solar system will officially have eight planets. If instead the diameter of Pluto becomes the new lower limit for defining a planet, then Xena will likely also gain official status as a planet. So far there have been no indications as to when a decision will be reached.
New Horizons will launch from Kennedy Space Center. The window of opportunity for launch begins on Tuesday and lasts through February 14, 2006.