LAUREL, Maryland -- Signals from a spacecraft 3 billion miles away swept over Earth on Tuesday, confirming that NASA's New Horizons probe survived its history-making flyby of Pluto.
"We are in lock with telemetry with the spacecraft," mission operations manager Alice Bowman declared.
The radio signals were received four and a half hours after they were sent out at the speed of light, and a full 13 hours after New Horizons made its close pass. But they electrified hundreds of VIPs, journalists and Pluto fans as if the main event had just happened.
The audience here at Johns Hopkins University Applied Physics Laboratory stood up, clapped their hands and waved American flags as each mission controller reported "nominal" status for the hardware that was their responsibility.
"We have a healthy spacecraft, we've recorded data of the Pluto system, and we're outbound from Pluto," Bowman finally declared just before 9 p.m. ET.
She said the procedure went "just like we planned it, just like we practiced."
The transmission not only assured the team mission controllers that the piano-sized spacecraft was in good health, nine and a half years after its launch, but it also held the promise that images and observations of Pluto and its moons would be streaming in from New Horizons for months to come.
The flyby actually took place at 7:49 a.m. ET Tuesday, with New Horizons coming within 7,750 miles (12,500 kilometers) of the dwarf planet's mottled surface. But the spacecraft was so busy making observations that it couldn't turn its antenna back to send the all-clear signal until hours later.
To mark the morning's occasion, 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. The picture featured the dwarf planet's bright heart-shaped region as well as the head of a dark "whale" feature. It was part of a "fail-safe" series of observations that were made just in case the spacecraft suffered a catastrophic failure during the flyby.
Mission scientists went into high gear, pointing to features in the photo such as a bright bull's-eye crater nicknamed the "whale's blowhole," a point that may be a frost-capped peak, linear streaks that may (or may not) hint at tectonic activity — and mounds of icy material on the surface.
The mission's principal investigator, Alan Stern of the Southwest Research Institute, was asked whether it was now fair to say that it snows on Pluto. "It sure looks that way," he replied. But Stern said he couldn't yet see any evidence of plumes or atmospheric hazes or clouds above the surface.
Stern said it felt good to get through the flyby.
"It's a moment of celebration, because we've just done the 'anchor leg,'" Stern said on NASA TV, using a track-and-field metaphor. "We have completed the initial reconnaissance of the solar system."
No new images were transmitted on Tuesday, just the telemetry reporting the spacecraft's health. The first post-flyby images and data are due to be received on Wednesday, and they'll continue coming down for the next 16 months.
The mission quickly captured the spotlight — in forms ranging from a Google Doodle and a New Yorker cartoon to a Baltimore Sun op-ed column in which White House science adviser John Holdren and NASA Administrator Charles Bolden hail New Horizons as "a new milestone" in exploration and discovery.
John Grunsfeld, NASA's associate administrator for science, said the heart of New Horizons' appeal is its status as the first mission to the last frontier — that is, the icy worlds that lie beyond the orbit of Neptune. "Pluto is kind of a capstone of our solar system exploration, and also opening up this new realm," he said.
New Horizons' findings will be making an impact on planetary science long after Tuesday's flyby, said U.S. Sen. Barbara Mikulski, the Maryland Democrat who championed the $728 million mission when it was threatened with cancellation 15 years ago.
"The fact is that we will be downloading this information for more than a year," she said, "and we will be analyzing it for a generation."