New Horizons phoned home.

NASA received official confirmation on Tuesday night that its spacecraft had successfully completed its flyby of Pluto.

The vessel sent word of its achievement 4.8 billion kilometres to mission control back on Earth.

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

The confirmation of a successful mission came 13 hours after New Horizons passed within 12,400 km of the dwarf planet at 49,900 kph.

Pictures from its closest approach should be available Wednesday.

Earlier on Tuesday, the spacecraft sent back the most detailed image of the dwarf planet yet.

Before the flyby, NASA posted the new image of Pluto to as a "sneak peek." The same image was posted to Twitter moments after the approach.

"Hello #Pluto! We're at closest approach. Congrats to all!" the .

The approach was made after the spacecraft travelled roughly 7.5 billion kilometres in a journey that began nine-and-a-half years ago.

NASA Administrator Charles Bolden said the flyby is a historic first for mankind, as it is the first time a space mission has explored a world so far away.

"The exploration of Pluto and its moons by New Horizons represents the capstone event to 50 years of planetary exploration by NASA and the United States," he said in a statement earlier Tuesday.

"Once again we achieved a historic first. The United States is the first nation to reach Pluto, and with this mission has completed the initial survey of our solar system, a remarkable accomplishment that no other nation can match."

As the spacecraft passed the mark at 7:49 a.m. ET Tuesday morning, crowds of scientists cheered at NASA's flight operations centre in Maryland and waved American flags.

Pluto

It will take a total of 16 months for the spacecraft to send back to Earth all of the data it collects.

 

Already, pictures of Pluto have been able to provide unknown detail about the dwarf planet.

The photos will provide information about the solar system's Kuiper Belt – a region filled with icy objects, including Pluto itself.

Alan Stern, the New Horizons principal investigator at the Southwest Research Institute, said the mission is now writing a textbook about Pluto.

"The New Horizons team is proud to have accomplished the first exploration of the Pluto system," he said in the statement. "This mission has inspired people across the world with the excitement of exploration and what humankind can achieve."

The U.S. is now the only nation in the world to have visited every single planet in the solar system.

When the spacecraft left on its mission to fly by and photograph Pluto in 2006, the icy planet was billed as a full-fledged planet. Since then, it's been demoted to dwarf status.

Pluto was first discovered in 1930 by Clyde Tombaugh. New Horizons now carries his ashes as a token of his discovery.

Congratulations pour in

Throughout the day, congratulations poured in for the space agency and the team behind the mission.

Famed British physicist and cosmologist, Stephen Hawking, posted a short video to YouTube, sending his congratulations to the team.

"The revelations of New Horizons may help us to understand better how our solar system was formed. We explore because we are human and we want to know," Hawking said.

"I hope that Pluto will help us on that journey. I will be watching closely, and I hope you will too."

Astrophysicist Neil deGrasse Tyson tweeted his thoughts on the historic mission, writing: "Were it not for NASA & kindred programs of discovery, I wonder what hope would remain for our species to rise above itself.

With files from The Associated Press