NASA held the Pluto flyby event at the headquarters for New Horizons — the Johns Hopkins Applied Physics Laboratory.

Scale models of New Horizons could be found around every corner of the campus.

Alan Stern, the principal investigator for New Horizons, speaks to the crowd at Johns Hopkins moments before New Horizons performed its flyby. It would take more than 12 hours before the world knew whether the spacecraft was still alive.

That didn't stop the crowd from celebrating. New Horizons team members, NASA staff, and guests filled multiple rooms to watch the countdown.

The crowd cheers as the countdown reached zero. A remix of Europe's "The Final Countdown" was playing in the speakers.

Guests and members of the media watch Bill Nye's reaction to the now-famous image of Pluto, which NASA released just before the flyby occurred.

Journalists pore over Pluto's details while they waited for the post-flyby briefing to begin.

Various New Horizons team members met with the media all week to offer insight and discuss the latest mission developments.

It will take 16 months to completely download the data from the spacecraft. “We are facing the Christmas that keeps on giving," said Kimberly Ennico Smith, a New Horizons deputy project scientist.

Chris Hersman, lead engineer of New Horizons, explains the spacecraft's trajectory with a mockup made from an iPhone 4, a pen, and a sliced up Dunkin Donuts cup.

Pluto's "heart" is not healthy, according to team scientist Bonnie Buratti. The bright region has been eroding for years to the extent that it was even visible before New Horizons showed it in detail.

Sylvia Kuiper (left), daughter of Gerard Kuiper (for whom the Kuiper belt is named), holds up an image of Pluto alongside Alden and Annette Tombaugh, whose father discovered Pluto.

John Grunsfeld, NASA's associate administrator for science, holds up the now-famous image of Pluto.

Grunsfeld and Stern watch a New Horizons media briefing.

Members of the media listen to Ellen Stofan, NASA's chief scientist, speak about New Horizons and the agency's future plans. A geologist by trade, she said she was fascinated by the increasing detail of the images, and that it was tough to resist drawing early conclusions about the makeup of Pluto and Charon. "I was looking on Twitter, so it's really hard to look at a Twitter photograph and start doing geology on it — but of course I was doing it anyway," she said.

Team scientist Bill McKinnon explains some of Pluto's features to the media.

McKinnon wore socks on flyby day that showed the phases of our Moon.

New Horizons has enough fuel to last until the 2030s but would require a major mission extension to still be doing science that far from now. Team scientist Fran Bagenal was asked if the spacecraft will ever get to study the boundaries of our Solar System. "We'll measure as long as we can," she replied, "and as long as we have money."

Tom Krimigis takes questions from the audience during a briefing. He has been a part of major space missions to each of the nine major planetary bodies in the Solar System.

Ann Druyan, one of the co-writers of COSMOS and Carl Sagan's widow, spoke at a panel on the day before the flyby. "I just briefly wanted to celebrate the fact that this continuity of minds that is science, that stretches back to antiquity, is the most precious thing we have. And if it is good enough to get us to the Kuiper belt in perfect synchronized, melodic grace — to do this so brilliantly — then it's good enough for us to really depend on it for the saving of our lives. We should be listening to the scientists and what they're telling us about the fate of this world."

Alan Stern (right) holds up an issue of The Planetary Report from 1990 that contains a plan to explore Pluto. Stern wrote the paper, and Robert Farquhar (left) was the study manager.

The spacecraft in Stern's plan looks similar to New Horizons.

Magician and entertainer David Blaine performs a trick with an audience member.

The audience member was instructed to pick one puzzle piece from a bin. The piece wound up being the only one missing from a separate, nearly complete puzzle of our solar system.

The auditorium at the Johns Hopkins Kossiakoff Center was where most of the main media briefings and NASA TV broadcasts were held. This was what the room looked right minutes before the doors were opened before the "phone home" event.

Volunteers sort the programs, stickers, and other promotional materials available for guests of the event.

The New Horizons team members who spoke on stage used these commemorative mugs.

Mission operations manager Alice Bowman (right) receives word that New Horizons has phoned home and that all systems are healthy.

Annette Tombaugh, daughter of the man who discovered Pluto, reacts to the news that New Horizons is alive.

The New Horizons team enter the auditorium at the Kossiakoff Center to a standing ovation.

Alice Bowman greets her team on stage.

A New Horizons team member celebrates with the other Pluto.

NASA's administrator Charles Bolden has an emotional moment on the stage shortly before speaking about the successful Pluto flyby.

"Today’s mission was just one more step on the journey of getting humans to Mars, because it gives us one more piece in the puzzle of our Solar System," Bolden said.

A New Horizons team member is interviewed moments after the news of the successful flyby.

The team assembled on stage during Charles Bolden's speech.

Alan Stern calls out the rest of the New Horizons team and asks them to stand up to receive recognition. Stern spent much of the week deflecting praise to his team, while his team did a fair share of praising his work. "You know, we’ve got Alan as the PI on this thing, and thank god for that because if it hand’t been for Alan Stern this mission would not exist," said Ralph McNutt, a New Horizons co-investigator. "It's a big family thing, we've been working together for a long time," Stern said.

Deputy project scientist Leslie Young celebrates the successful flyby.

New Horizons project scientist Hal Weaver (right) and his wife speak to the family of Clyde Tombaugh, the man who discovered Pluto.

New Horizons team members pose with wearable versions of the spacecraft, made by Johns Hopkins students.

Alice Bowman receives a standing ovation from the audience.

Hal Weaver celebrates the news that New Horizons is alive.

John Grunsfeld, Alan Stern, and Alice Bowman hold up nine fingers each, known to the New Horizons team as the "Pluto salute" — a nod to their belief that Pluto should be recognized as the ninth planet in our Solar System.

Alice Bowman receives a hug from NASA administrator Charles Bolden.