According to NASA, 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 dwarf planet and begin studying its far side.
"We have a healthy spacecraft. We've recorded data of the Pluto system and we're outbound from Pluto," announced mission operations director Alice Bowman. She was drowned out by cheers and applause; Stern ran over to give her a hug.
Confirmation of New Horizon's success came 13 hours after the actual flyby. It takes four and a half hours for signals to travel from New Horizons to Earth. The signal was received, Bowman said in a NASA press conference Tuesday night, at 8:52:37 p.m. ET.
NASA says it will hold a press conference at 3 p.m. ET on Wednesday, July 15, to share data and the newest, highest-resolution photos of Pluto.
President Barack Obama congratulated the New Horizons team on Twitter.
Pluto was discovered in 1930 by Clyde Tombaugh, then 23, who was born in Streator, Illinois. Adler Planetarium astronomer Dr. Lucianne Walkowicz told ABC 7 reporter Frank Mathie that the pictures are, truly, stellar.
"The first thing I see is detail. Prior to this our pictures, even with the Hubble telescope, have been of this sort of greenish, mushy pea. And now we can see craters and dark patches over the surface," Dr. Walkowicz said.
The new, clear images of Pluto have prompted awe, wonder and excitement in people across the country and the world. It has also provoked some keen observations. One Twitter user pointed out the huge plain that some have called heart-shaped bears a striking resemblance to something else that shares its name with our former ninth planet.
"The best thing about the Pluto image from NASA today," he tweeted, "is the silhouette of Pluto the dog right on it."
The best thing about the Pluto image from NASA today is the silhouette of Pluto the dog right on it. pic.twitter.com/hVqD5QTwGz— Scott Johnson (@scottjohnson) July 14, 2015
The Associated Press contributed to this report.