Pluto's 'Honor' as Full-Fledged Planet May Be Restored

NASA's New Horizons spacecraft's fly-by around Pluto is being called true exploration and phenomenal.

Scientists say it may restore Pluto's "honor" as the planet wasn't as small as once thought when it was redesignated as a dwarf planet.

It's all part of a tour of the solar system by NASA that started almost a decade ago.

The arrival of the exploration craft near Pluto makes the United States the only nation to visit every single planet in the solar system.

"This is a tremendous moment in human history," John Grunsfeld, NASA's science mission chief, said at a news conference.

NASA said the spacecraft - the size of a baby grand piano - swept to within 7,700 miles of Pluto at 31,000 mph. It was programmed to then go past the planet and begin studying its far side.

To commemorate the moment of closest approach, scientists released the best picture yet of pluto, taken on the eve of the fly-by.

Principal scientist Alan Stern promised even better images will start "raining" down on Earth beginning Wednesday.