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How Pluto's most spectacular image was made—and nearly lost

By the end of the day on 14 July, the stunning picture of Pluto above would become iconic—the most “liked” image ever on NASA’s Instagram account. Even U.S. President Barack Obama would tweet it out.

But the night before, at 11:07 p.m. EDT, the image was scattered across 675 kilobits recently collected from the edge of the solar system. NASA's New Horizons spacecraft had finished a 44-minute transmission to a 70-meter radio dish outside of Madrid and those data coursed through fiber optic lines, across the Atlantic Ocean, to a server at Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Maryland. There, a special team was waiting to create the final image, a process that would be imbued with unexpected drama—including a brief panic that the image had been lost.

Hal Weaver, the project scientist for New Horizons, watched the data packets accumulate one by one on the server, and waited for an automated process to collate them into a FITS file—a rudimentary image. It would be a raw, lossy, black and white image of Pluto, the first to fill the frame of the spacecraft’s camera. And it would be the last image sent to Earth before the probe spent 22 hours straight observing the dwarf planet during its closest approach. But Weaver didn’t want to look at it. He wanted to savor the moment with virgin eyes, along with the rest of the science team, at a 6 a.m. meeting the next morning. So he grabbed a FITS file with LORRI in the name—the New Horizons camera taking the image—and without sneaking a peek, stuck it on a thumb drive. At 11:15 p.m., he walked it over to the “fishbowl,” an airy room in building 200 at APL.

Assembled there were the five scientists appointed earlier in the day to toil through the night sprucing up the image. They called themselves the Union of Amalgamated Pluto Colourists, a half-joking name for a collective with American, British, and Canadian roots. Two of them, Simon Porter and Tod Lauer, would polish the raw black and white images. Another two, Carly Howett and Alex Parker, would overlay color information. John Spencer, a senior scientist on the mission, was to oversee the effort. All were excited, running on little sleep, and fully aware of the image’s viral potential. They had been instructed not to email the image around—thus the thumb drives—or to even talk about it. The usual data pipeline—a set of servers at Southwest Research Institute in Boulder, Colorado—had been shut down to limit access to the files. “There was a lot of sensitivity about this image,” Howett says. “We understood as a team why that was.”

Parker took the thumb drive from Weaver, who then left the room. The Union gathered around Parker’s laptop for the big reveal. There in the middle of the screen was a big gray orb—but one way too gray to be Pluto. That’s because it wasn’t. It was Charon, Pluto’s largest moon. “The first reaction is: there’s something seriously wrong,” Parker says. “Did the spacecraft point at the wrong thing? Oh God, is this a crisis? And then it’s like, no, this is the Charon image we saw earlier today. It’s just the old file.” Weaver had copied and pasted the wrong file. They rushed to Weaver’s office to let him know.

But Weaver couldn’t find the right file. The packets were there, but no FITS file for Pluto. By 11:30 p.m., he began to freak out. He called and woke up one technician at home. He tried to raise another technician at a hotel to no avail. In the end, he found a file, identical to the one he wanted, in a directory labeled PRELIM. Only later would he realize his mistake: The file he wanted was there all along, but in a directory called HICAD, not in the PLUTO directory where he was searching. “I said, ‘Oh my God, I can’t believe it, I was querying the wrong directory,’” he says. “I had been up a lot.”

At 12:40 a.m., Weaver called the Union into his office, where he brought the image up on his Apple Thunderbolt display. This time, there would be no punctilious averting of eyes. The team looked over his shoulder at the most detailed view of Pluto ever seen. Some 4.7 billion kilometers away, a spacecraft had converted the light reflecting off of a mottled, never-before-visited surface into a stream of numbers. These numbers had now been converted back into dots on a screen that had a peculiar telekinetic effect on the jaws of those present. “It got a bit surfer-y: ‘Whoa,’” Howett says.

NASA’s New Horizons team reacts to the first full-frame images of Pluto shown at a 6 a.m. science team meeting on Tuesday, 14 July.

Howett’s eyes were first drawn to the icy “heart” in the middle of the image. Parker remembers seeing the dark regions just next door, as well as craters, ridges, and shadows that suggested significant topography. Lauer, an extragalactic astronomer, took in the global view: Pluto, the fuzzy astronomical object, had been transformed into a crisp geological world. He pointed to various features on the screen with a Dumbledore wand he had picked up at a Harry Potter store in London. (“If I’m going to be doing tricks with image processing, I might as well have a wand,” he wisecracked later.) Weaver, normally mild, was a bit amped up in the moment. “This is fucking unbelievable,” he announced to the others.

But the researchers could not dally long, even though Spencer had a hard time dragging himself away from Weaver’s office.  At 12:55 a.m., Weaver emailed the Union the raw file they would end up working with, and went home for some sleep. It took just 10 minutes for Lauer and Porter to apply their algorithms and polish the black and white image; then went to their hotels soon thereafter. Parker and Howett’s jobs took longer. They had to overlay lower resolution color information, acquired the previous day when Pluto was in a different global position. It required a lot of tweaks. By 3 a.m., they were nearly there. Howett knew she was done when Spencer, a taciturn perfectionist, said, “Yep, that’s good.”

Parker brought up a blank email to Weaver. He attached the polished black and white image, and then the colorized one, a relatively small 558 kilobit .png file. Atop the email he wrote, “WARNING: Awesome images below”—just in case Weaver wanted to keep the color image secret until the 6 a.m. meeting. At 3:13 a.m., Parker hit send. The three remaining members of the Union of Amalgamated Pluto Colourists went back to their hotel for an hour or so of fitful sleep. No way were they going to miss the reactions of their compatriots back at APL. “It’s a once in a lifetime opportunity and you can sleep when you’re dead,” Howett says.

The 6 a.m. science meeting, team members only, came wedged in time with another big mission moment: Less than 2 hours later, New Horizons would make its closest pass past Pluto. The team would count down that moment and celebrate it, even though it had a hint of unreality—they wouldn’t find out about the spacecraft’s success until that night. But there was nothing unreal about the images on display at the 6 a.m. meeting: Here was a world conjured into detailed, living color. Weaver and mission principal investigator Alan Stern revealed the three images in succession: raw, polished black and white, then color. “This is history being made,” Weaver said. Jaws dropped all over again. Parker and Howett, sitting next to each other, exchanged knowing glances, and sent deferential nods across the room to Lauer and Porter. By 7 a.m., the image was out on Instagram, and it began its inexorable spread across the globe.

Parker feels pride, but knows that the image was a collective effort that began many years before the spacecraft’s 2006 launch, and one that will stretch beyond the solar system. “If you’re going to credit who made this image, you have to credit a thousand people,” Parker says. “I can’t say that it’s my image. None of us can. No one person can. We put the bow on it.” 

*See Science’full coverage of Pluto, including regular updates on the New Horizons flyby.

(Video credit: NASA)