Before the Pluto Flyby: What Has New Horizons Seen So Far?

NASA's New Horizons mission is scheduled to make history with the first-ever flyby of Pluto on Tuesday morning at 7:49 a.m. Eastern time. Launched in January 2006, the spacecraft has been on course for nearly nine and a half years to reach its primary target; at the time of the flyby, it will have traveled for 3,462 days.

Along the way, New Horizons has captured images of Jupiter and its closest moon, Io; a faraway snapshot of Neptune; and increasingly detailed images of Pluto and its largest moon, Charon.

The images and data that have returned so far are "already mouthwatering," said Alan Stern, principal investigator for New Horizons, during a Monday morning press conference just one day ahead of the historic event. NASA will release additional images over the next several days of the Pluto system, which Stern called "enchanting in its strangeness [and] its alien beauty."

The resolution of images New Horizons can capture will continue to improve dramatically during the countdown to the closest approach, when the spacecraft will be 7,750 miles from Pluto's surface. Within 24 hours, image resolution will go from 15 kilometers per pixel to less than 100 meters per pixel, Stern explained. If you were flying that distance above New York City with New Horizons's imaging capabilities, you would be able to distinguish the individual ponds in Central Park, according to project scientist Hal Weaver.

Pluto is one of the largest objects in the Kuiper Belt, the third zone of the solar system beyond the terrestrial planets and the gas giants, Stern said. Since the belt is composed of some of our solar system's most primitive material, according to Weaver, scientists are hoping the images and other information New Horizons collects will provide them with a deeper understanding of the formation and early days of the solar system.

Jim Green, head of planetary science at NASA, told Newsweek last month that the flyby marks the completion of NASA's "initial reconnaissance of the solar system."