Artist's concept of the New Horizons spacecraft as it approaches Pluto and its largest moon, Charon, in July 2015. NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

In 1929, the Lowel Observatory, located in Flagstaff, Arizona, hired a young man by the name of Clyde Tombaugh to take over the search for a planet beyond Neptune, a search that was started by astronomer, Percival Lowell in 1905. Tombaugh had drawn very meticulous sketches of Mars and Jupiter that he had viewed through a nine-inch telescope that he had made and sent them to the observatory hoping for some advice from the people who worked there. Instead he was offered the position as junior astronomer. Tombaugh's job involved taking photographs of the same section of sky and comparing them. When flipping between the images Tombaugh noticed an object among the hundreds of thousands of points of light, that had been moving from one position to another, located near the area Lowell predicted there to be another planet. February 18, 1930, was the eureka moment, he saw Pluto for the first time.

Clyde died in 1997 in Las Cruces, New Mexico at age 90. He was the only American to ever find a planet in the solar system. In 2006, the International Astronomical Union (IAU), defined exactly what a planet is in our solar system. Pluto was reclassified as a minor or dwarf plantet. Clyde's wife Patsy stated that the IAU's decision to remove Pluto's planetary status would have been accepted by Tombaugh, ¨He would understand they had a real problem when they discovered several of these things flying around."

The New Horizons Spacecraft, the spacecraft on the first mission to Pluto was launched on October 17, 2011. New Horizons is expected to fly past Pluto in July 2015, just under 5 billion miles away from Earth, and continue on its journey to interstellar space after leaving our solar system.

American planetary scientist, Alan Stern, announced on June 14, 2007 that they would be including some of Tombaugh's ashes on the mission to Pluto. A specially designed memorial canister, about two inches wide by half an inch tall, was attached to the upper deck inside the piano-sized spacecraft. Stern also included a memorial that he wrote, "Interned herein are remains of American Clyde W. Tombaugh, discoverer of Pluto and the solar system's "third zone." Adelle and Muron's boy, Patricia's husband, Annette and Alden's father, astronomer, teacher, punster, and friend: Clyde W. Tombaugh (1906-1997)."

Read more:

New Horizons Web Site

Watch the launch of New Horizons