NASA's New Horizons spacecraft has broken the closest-approach mark to Pluto set by NASA's Voyager 1 in January 1986.

On Dec. 2, New Horizons, after 2,143 days of high speed flight of more than a million kilometers per day, broke the 1.58 billion kilometers set by Voyager 1.

"Although we're still a long way - 1.5 billion kilometers from Pluto - we're now in new territory as the closest any spacecraft has ever gotten to Pluto, and getting closer every day by over a million kilometers, says New Horizons principal investigator Alan Stern of the Southwest Research Institute.

As it approaches Pluto, New Horizons will continue to set proximity-to-Pluto records every day until its closest approach of about 7,767 miles (12,500 kilometers) from the planet on July 14, 2015.

At its current distance to Pluto, the planet remains just a faint point of light as seen from New Horizons. However, in mid-2015, the planet and its moons will be so close that the spacecraft's cameras will be able to spot small features of the planet.

"We've come a long way across the solar system," says Glen Fountain, New Horizons project manager at the Johns Hopkins University Applied Physics Laboratory. "When we launched [on Jan. 19, 2006] it seemed like our 10-year journey would take forever, but those years have been passing us quickly. We're almost six years in flight, and it's just about three years until our encounter begins."

Currently, New Horizons is in hibernation with all but its most essential systems turned off and speeding away from the Sun at more than 55,500 kilometers per hour.
According to operators at the Applied Physics Lab, they will "wake" the spacecraft in January for a month of testing and maintenance activities.