by Alan Stern
Now, with just days to go before the flyby, it was time to decide how big a timing update to radio up to New Horizons. The meeting to make this decision was structured so that at the end of all the discussion, after all of the navigation calculations were reviewed and the consequence report results were shown, after everybody on the team had asked all their hard questions and probed at every what-if, Mark Holdridge, who rode herd on this process, would go around the room, asking each technical lead if he or she was go or no go for the timing update. That polling started with the system engineers and went through mission operations, then navigation, then the project scientists, and then to project manager, Glen Fountain. As the PI, and the final arbiter, Alan would be last, making the ultimate decision. Alan:
Mark went around the room, and everybody was giving “Goes.” I was pretty surprised. We were well inside the nine-minute box we had to be in, and while Leslie’s report showed that a timing update could make a few observations work better, none were going to fail. I knew that our team wanted to score as high a grade as it could on every observation, but from my perspective, we were already lined up to get a straight-A report card. Further, the timing knowledge update was untested on the spacecraft. I was surprised that no one was asking, “Was the risk of making things worse if the timing update didn’t work as planned, worth the tiny gains in score it offered?” The poll got all the way up to Glen Fountain, who as project manager was just before me in the pecking order, and he too gave a “Go.” I couldn’t believe it! After all, we had just been through a “near death” experience days before, in which we’d overlooked something subtle and sent the spacecraft into safe mode over the Fourth of July weekend. So, I was a little incredulous that everyone wanted to do this, even Glen, and that no one was thinking that, well, “better” might be the enemy of “good enough.”
In my mind, the situation was analogous to our second launch attempt in Florida back in 2006 when everybody said “Go” and I had to stop it, because I didn’t want to have the control center at APL operating on backup power during launch. I didn’t like doing it, but I derailed that entire launch attempt because I didn’t want to take a risk that everyone else had accepted.
Just like that 2006 launch poll, the timing update poll had been unanimous until it got to me, but I said, “No Go,” and I explained my reasoning. So I asked the team, “Am I missing something? Is there a must-do reason to try out the timing knowledge update when we’re already way inside the timing box?” No one pushed back, even when I asked twice. So I vetoed the timing knowledge update.
After we ended the meeting I went back to my office on the other side of the APL campus and found I’d already received a number of emails and other messages from some who’d been there. Every single one of them expressed relief that I’d resisted group-think, and made that call, avoiding “better” for good enough. I was glad, too. There were still a hundred ways the flyby could fail—we didn’t need this unnecessary one.
A MAELSTROM IN MARYLAND
As the spacecraft barreled onward toward Pluto, press coverage on television, in newspapers, and on the internet was building rapidly. So were the crowds at APL.
The press and public activities there were held in the Kossiakoff Center, a building at the front of the APL campus, with a large auditorium, a complex of offices and meeting rooms for press activities, briefings, and interviews, and an open space for large crowds of visitors. As people arrived, they were given different-colored badges to differentiate among press, visitors, VIPs, and staff. During the week of final approach, hundreds of reporters, correspondents, and documentarians arrived, from media outlets in North and South America, Asia, Europe, Australia, and Africa.
But it wasn’t just press and friends and family coming to APL. In mid-July 2015, the Applied Physics Laboratory in itty-bitty Laurel, Maryland, became the only place to be for hard-core space freaks: there was simply no way to miss being present for the first flyby of a new planet in a generation. The internet made it possible to learn what was going on, to see new images, and enjoy the building Plutomania from almost anywhere on Earth. But there is still something irreplaceable about human beings gathered together for common purpose, to experience something larger than life.
The public relations team at APL had managed large public events before, but it was caught off guard by the massive and ever-growing outpouring of interest in New Horizons. By the morning of July 14, the day when New Horizons reached Pluto, the crowd there was more than two thousand strong, the phones in the press areas were ringing off the hook, and the mission and NASA web servers were churning furiously with hundreds of millions—and eventually billions—of visits from people tuning in from every continent of Earth.
The crowd at APL included a who’s who of planetary exploration and many pivotal figures in the exploration of Pluto. Alan’s old professor Larry Esposito, whose POSSE proposal had narrowly lost out to New Horizons fourteen years earlier, was there. In an alternate reality this could have been his flyby, but there he was, smiling and sharing in the excitement. Original JPL Pluto mission study leads Rob Staehle and Stacy Weinstein were there, too. And so were key people who had played decisive roles in making New Horizons happen, such as Mike Griffin, who had been APL’s space department director during the late-stage construction of New Horizons and then went on to be NASA Administrator during the run-up to launch and the early years of the mission. Members of the current NASA brass were also out in force, such as former space shuttle commander Charles Bolden, who was then serving as NASA’s Administrator. Bolden took special delight in the company of the “Pluto Pals”—an excited gaggle of nine-year-olds who were all born on the day of the New Horizons launch, who had been invited to join in the thrill of the flyby.
Celebrity sightings added something more, something almost surreal to the atmosphere at APL. Among the luminaries who visited were Bill Nye, Senator Barbara Mikulski, Queen guitarist Brian May, illusionist David Blaine, and the rock band Styx.
All the while, of course, the New Horizons team members were working behind the scenes to carry out the flyby. Recognizable in their crisp black team polo shirts with the New Horizons mission patch on the chest and a small American flag on one shoulder, many found themselves mobbed for interviews, autographs, handshakes, and selfies with bystanders each time they emerged from backroom meetings.
PLUTO’S HEART
In the week before the close flyby, years of speculation began to melt away as Pluto revealed more and more of itself, growing larger and clearer in the successive images sent back to Earth. We had long known, since the Hubble images and Marc Buie’s deft construction of a crude surface map created from them many years before New Horizons arrived, that Pluto’s surface was varied, with sharp contrasts between bright and dark areas. But there had always been the possibility that these diverse features were merely “painted on” the surface.
As team scientists began to recognize patterns in the images, they did what humans have always done: they started to give names to things. These first names, of course, were inherently temporary, as Pluto’s true appearance was being clarified with every passing day. And because these names felt disposable, they were often whimsical (like the equatorial “brass knuckles” described earlier). One dark elongated region appeared near the equator, shaped vaguely like a cartoon whale, and that’s what it was called, the “whale.” Then the flyby hemisphere’s brightest and largest spot, which Alan had first called “India,” again rotated into view, appearing much larger than the last time it had been seen, one 6.4-day-long Pluto rotation before. Now it appeared rounded, with a double-lobed northern section, and in the south it tapered toward a sharp point. NASA press liaison Laurie Cantillo saw it and immediately asked, “Does anybody else notice that bright feature has the shape of a heart?” and once she said it, no one could get it out of their minds. It did look just like a heart!
The next day NASA made a press release announcing “Pluto has a heart,” which promptly wen
t viral. There couldn’t have been a more perfect hook for even greater public engagement as the meme of Pluto’s heart soared in social media trends. It became the iconic feature of Pluto, creating an emotional attachment for this small, previously indistinct planet at the edge of our planetary system. Within just days, the “heart” became enshrined on countless internet cartoons, on T-shirts, on dresses, on refrigerator magnets, on pieces of custom jewelry, and on children’s plush toys. As Laurie Cantillo later put it, “In the summer of 2015, the world ‘hearted’ Pluto.”
“I COULDN’T TAKE MY EYES OFF IT”
Near midnight on Monday, July 13, NASA’s Deep Space Network of communications antennas received a precious package from New Horizons: the last and best data that the spacecraft would send down until the day after closest approach. This was the “fail-safe” data set designed to ensure that even if New Horizons was destroyed by some undetected debris, there would be a small but valuable scientific return from the mission.
After that, for more than a day, New Horizons would be far too busy taking data close to Pluto to look away and point its dish antenna to communicate again with Earth. Instead, it would be doing what it was built to do: photographing Pluto’s surface in detail; mapping its surface composition; studying its atmosphere; then turning to image Pluto’s giant moon, Charon, and briefly studying each of Pluto’s four small moons. Some 236 separate scientific observations of each of the six bodies in the Pluto system, using all seven of the New Horizons instruments, were made over the next roughly thirty hours.
All the fail-safe data—including new composition spectra, atmospheric spectra, and this big Pluto image—reached Earth just before midnight on July 13. The crown jewel of the fail-safe data was a single full-frame, black-and-white image of one entire hemisphere of Pluto, taken just before the transmission began. By far, it would not be the most detailed image of Pluto that New Horizons would get, but it was made from a range three times closer than any previous image sent to Earth and was at the time the highest-resolution and most spectacular image of Pluto ever taken.
John Spencer led a handpicked team of just five New Horizons scientists, including Hal Weaver, who would process this image. They stayed up most of the night, getting it ready to release to the world the following morning. If there ever was a group of scientists who did not mind pulling an all-nighter, this group was it. John recalls:
We already felt we were in a very privileged position just to be part of New Horizons at all, but to be the five people who were first seeing this planet that billions of people were waiting to see was amazing. And we couldn’t believe what we were seeing in that image: you immediately could see that some parts of Pluto’s surface were heavily cratered and ancient, and that other areas seemed remarkably crater-free, and therefore much younger. There was a huge range of ages across the surface, something almost unprecedented!
Alan:
I wasn’t able to be part of the overnight image processing team, because I would have to be ready for a twenty-four-hour-plus day of media coverage, press conferences, and mission critical operations the next day. I think my schedule allowed a four-hour window for sleep that night. The next morning, though, when I saw that jaw-dropping, fail-safe image of Pluto, I was simply stunned. This wasn’t another fuzzy image made from too great a distance that only showed vague details—this one was razor sharp, and for the first time revealed Pluto’s amazing geological beauty. With that image, Pluto became a place, just like Mars or Titan or even Earth, and it revealed itself to be a place beyond my wildest imagination. You could see mountain ranges, craters, canyons, giant ice fields, and more! It was amazing: Pluto was gorgeous. We’d hit the jackpot. I couldn’t take my eyes off it.
16
EVEREST
A FINAL COUNTDOWN
The actual moment of closest approach to Pluto was to occur at 7:49:50 A.M. EST on Tuesday morning, July 14. But when this moment came—strangely for such an important event—there was nothing to see, and nothing new to show or to know. As we described before, the spacecraft was busy taking data, rather than communicating with Earth. It was skimming less than eight thousand miles above the surface of Pluto, working feverishly to get the goods it had come for. Back at APL, the New Horizons team marked the moment with a televised public countdown to celebrate the milestone.
The giant auditorium and the cavernous overflow area at APL’s Kossiakoff Center were brimming beyond capacity, with bodies crammed in at the fire marshal’s legal limit. Digital displays showed hours, minutes, and seconds left to reach Pluto, now all down to zeros except for the seconds counter. As those final seconds counted away, Alan led the crowd in a ten … nine … eight countdown rally. Each number was shouted in unison by the mission team and the massive swarm of space fans. At the second before closest flyby, a roar of cheers erupted, turning into a sea of smiles and furiously waving American flags.
At the same moment, at T−0, as New Horizons was passing closest approach to the planet it had traveled so far to explore, the full-frame fail-safe image of Pluto, which had been publicly released on the internet barely an hour earlier, was projected onto the jumbo display where the approach countdown had been, creating a visceral feeling in the room of being there, at Pluto, in the very moment.
Shivers ran up spines. Some people hooted or cheered. Some cried. Alan, with a few of the team members and Clyde Tombaugh’s children held up a poster-size copy of that old 1991 U.S. postage stamp that read PLUTO NOT YET EXPLORED. But on the poster, “NOT YET” had been crossed out so that it now read PLUTO … EXPLORED. Images of that moment also went viral.
Meanwhile, out there on its own, deep in the Pluto system, New Horizons was doing what it had been designed and built to do a dozen years before. As it flashed past Pluto and its five moons that day, it was gathering a library of data so vast that it would take sixteen months to send it all back to Earth. If New Horizons survived, and if the flyby all worked. But had it?
It would be fourteen hours before the phone-home message would be sent and then would reach Earth, 14 hours before the team and the world would know.…
WAITING
While everyone waited for New Horizons to check in with the phone-home message, there was a public to be served. So NASA and the New Horizons project had arranged for a full day of programming around the flyby. John Spencer:
The rest of that day was just a blur of media, mostly. I spent pretty much the whole day at the Kossiakoff Center talking to journalists and TV people, as did pretty much everyone else on the team.
Alan recalls, “The interest was relentless. Everywhere we went that day and the next we were mobbed by long lines of journalists and autograph seekers.”
It was probably just as well to keep the team busy with press during encounter day so as not to spend their time worrying about their spacecraft.
That afternoon, NASA hosted a public panel discussion with science team members describing their first detailed impressions of Pluto and Charon based on the fail-safe images and other data. Jeff Moore discussed the overwhelmingly beautiful, aesthetic appearance of Pluto, pointing out that not even the most imaginative space artists had made a painting as stunning as the real thing.
And it was true. If you compare the actual Pluto we now know to artists’ conceptions made before the flyby, none of the art comes anywhere near the striking splendor of the planet itself. In Jeff’s words, it was another example of “Nature outdoing our imaginations every time.”
Jeff then went on to describe some preliminary geological interpretations and showed a map with some of the new, informal names being tentatively used by the team to refer to features across Pluto’s surface. The Kossiakoff audience applauded vigorously when he mentioned that the “whale” had been given a provisional name certain to please any fan of classic sci-fi: “Cthulhu.”
Mission scientists Will Grundy of Lowell Observatory and Cathy Olkin of SwRI showed new color images. Will focused on the just-made discovery of Charon’s dark
northern polar cap—something completely unexpected, because it is unique in all the solar system. Will ventured a hypothesis that some of the escaping gases from the atmosphere of Pluto might be condensing out onto the cold north pole of Charon and then being chemically processed by solar ultraviolet light, producing organic molecules that mantled the pole of Charon. If this turned out to be correct, it would imply a startling physical bond between Pluto and its giant moon.
Cathy, a versatile researcher who had played many key roles on New Horizons, including as the deputy PI of the color imager inside the Ralph instrument, showed a “stretched” (i.e., digitally exaggerated) color image of Pluto that demonstrated how different places on Pluto exhibited distinctly different colors. That image—which Cathy described as “psychedelic”—was greeted by gasps and a wave of wows from the audience. She then showed that Pluto’s heart also has two very different colors, with the western lobe being whiter than the eastern lobe, which was markedly more blue. Also in that color-stretched view, Cathy noted that Pluto’s north pole could be seen to be more yellow than the rest of the planet.
Randy Gladstone, also from SwRI and the head of the New Horizons atmospheres science theme team, then reported that Pluto’s diameter had been measured to be 1,472 miles (later revised upward to 1,476 miles): larger than almost anyone had predicted. Alan then took pleasure in pointing out that this meant Pluto was, after all, larger than any other of the small planets in the Kuiper Belt, laying to rest the hope by some that dwarf planet Eris was larger than Pluto. As to those hoping Pluto was the second-largest body in the Kuiper Belt, Alan declared to the combined in-person and broadcast audience, “Well, now we can dispose of that.”
Then the program was opened up to questions. Someone asked, “Why, in the largest crater seen on Charon, is the rim bright but the interior so dark?” John Spencer replied that the crater interior is the area that receives the most heat during an impact, and that there could be something about the material Charon is made of that turns dark when it is heated during crater forming impacts. Then he added, wryly, “That’s one theory; but I just thought of it, which probably means it’s wrong.” That got laughs and applause, because it perfectly captured the atmosphere of instant, speculative science that occurs during a spacecraft flyby of a new planet, when the data is coming down faster than anyone’s ability to make careful science of it.