Celebrating New Horizons' astonishing photos of Pluto

LAUREL, Md. — If everything went according to plan, NASA’s New Horizons probe zoomed past Pluto on Tuesday, marking the climax of a first-of-its-kind mission that was launched nine and a half years ago. But we’ll have to wait until more than 13 hours after the encounter to hear for sure that it did the deed.

The piano-sized spacecraft is so busy taking pictures and making observations that it can’t turn its antenna around immediately to flash a message to Earth. And even when it does, it’ll take four and a half hours for the signal saying “I’m OK” to make the 3 billion-mile trip from beyond Pluto to Earth.

The flyby took place at 7:49 a.m. ET Tuesday, with New Horizons coming within about 7,750 miles (12,500 kilometers) of the dwarf planet's mottled surface. To mark that event, science team members and VIPs gathered here at Johns Hopkins University Applied Physics Laboratory, where the mission has its operation center.

When the appointed time came, well-wishers applauded, waved American flags and chanted "USA! USA!" To mark the milestone, NASA released a colorized view of the dwarf planet that was sent back to Earth before New Horizons went out of contact on Monday night.

Article by NBC News' Alan Boyle. Read more at NBCNews.com.

Pluto nearly fills the frame in this image from the Long Range Reconnaissance Imager (LORRI) aboard NASA's New Horizons spacecraft, taken on Jul. 13, 2015, when the spacecraft was 476,000 miles from the surface. 
Members of the New Horizons science team react to seeing the spacecraft's last and sharpest image of Pluto before closest approach later in the day at the Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Md. on Tuesday, Jul. 14, 2015.  
Guests and New Horizons team members countdown to the spacecraft's closest approach to Pluto at the Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Md. on Tuesday, Jul. 14, 2015. 
Annette Tombaugh-Sitze, daughter of Clyde Tombaugh (the discoverer of Pluto), celebrates with others at a countdown to the New Horizons spacecraft's closest proximity to Pluto at Johns Hopkins University Applied Physics Laboratory in Laurel, Md., on Jul. 14 2015. 
The New Horizons spacecraft lifts off aboard an Atlas V rocket at Cape Canaveral, Fl. on Jan. 19, 2006.