Chasing New Horizons

by Alan Stern

  That was all it took. The PI was No Go. The launch was scrubbed. Thousands of visitors and hundreds of launch personnel would once again have to wait, as would the exploration of Pluto. Again, the rocket was drained of its cryogenic propellants, and the launch crowds dispersed to the area beaches, nature reserves, restaurants, beds, and bars.

  Meanwhile, the launch team itself continued working, and looking at weather forecasts for the next few days. Alan asked APL to get a second generator in place, a second source of backup mission control power, so this couldn’t happen again. APL agreed, reporting that it could have it in place by evening.

  All of this launchus interruptus created an interesting dynamic. There was so much to do leading up to the day and the moment of launch, and with every attempt, all of it had to be repeated. Each time the launch team had to fuel, unfuel, refuel, and engage a massive amount of machinery and personnel—across the United States and across the world—to be geared up for the next launch attempt.

  For those not directly involved in the launch—the bystanders, press, and team members there with families to witness their baby leave the planet—there was a Groundhog Day aspect to the repeated launch attempts. The various mission contractors threw hotel parties the night before each launch count, catering the exact same foods and drinks each time. Although the launch and mission teams were hard at work, there was a whole other life of parties going on for all the visitors. That, combined with understandable prelaunch anxiety, and a little sleep deprivation, made the entire repeating pattern seem a bit surreal.

  IT SEEMED LIKE SCIENCE FICTION, BUT IT WASN’T

  After taking a day off for the launch crew to take a break, on Thursday, January 19, it was time to try again. The morning was chilly but sunny, and there was almost no wind, just a scattered deck of low clouds. The feeling of the crowd was guardedly optimistic. Over at the ASOC, the mood was businesslike for the third countdown and launch attempt for New Horizons.

  On this try, the drama became about the clouds and whether they would become broken enough to fly, so once again an important Go/No Go became that of the launch weather officer. Due to the changing positions of the Earth and Jupiter in their orbits, the launch window opened a little bit earlier each day. So on the 19th, the first attempt was set for 1:08 P.M. Eastern Time. The clouds came and went, resulting in a series of short delays as the Atlas team tried to find a time that would allow their rocket to dodge the clouds. Finally, a new “T−0” time was set for 2:00 P.M. The clock ticked down all the way down to T−4 minutes, and the mandatory ten-minute hold kicked in for all of the engineers and launch officers to make their final checks before the sprint to launch.

  A group of old friends from the New Horizons science team had gathered at a viewing site, anxious for their baby to take flight after so many years of hard work proposing and building and planning for its journey to Pluto and the Kuiper Belt. Science team geology and geophysics team lead Jeff Moore was there with his daughter and his mom. Geologist Paul Schenk was with his husband, David; Leslie Young was with her husband, Paul. Bill McKinnon had his kids in tow. Carter Emmart and David Grinspoon, who had both worked closely with the team on public outreach, were also there, sharing in the anxious excitement. Planetary astronomer Henry Throop prowled with his camera, smiling and shooting pictures of everyone and everything, capturing what could, if they launched today, turn out to be a pivotal moment in their lives. They had all been staring at the Atlas, waiting for it to launch, for days now. But it had just been sitting there, steaming off liquid oxygen in the Sun. Even from miles away it looked enormous, like a prominent skyscraper built along the shore. In an odd way, it seemed permanent, and it was hard to imagine that something so dramatic was about to make something so large lift off and fly away.

  A tense hush fell over the viewing site when the clock picked up after the hold at T−4 minutes. It was the first time New Horizons had gotten so close to launching.

  Back in the ASOC, Alan was at his console. Everything was going exceptionally well, save one minor portent. Alan was taking careful notes in his project diary using the same pen that he’d used for all of the previous countdown attempts and all of the launch rehearsals and simulations. Suddenly, just minutes before launch, the pen ran out of ink. “What? Wait. Why now?” he thought. But the moment passed and he shook off the seeming omen.

  Four minutes ticked down to three, then two, then one. In the final prelaunch poll Alan and all of the other launch managers gave their “Go’s.” And then, with his launch responsibilities complete, and just thirty seconds left in the countdown, Alan stood up, took his headset off, and ran as quickly as he could to a secret door he had found earlier, the only unlocked outside door in the ASOC.

  Out at the viewing site the crowd held its collective breath as the countdown ticked away through its final seconds. The launch team’s commentary could be heard over the public address system:

  “Third stage is Go.”

  “Roger.”

  “Minus twenty-five seconds.”

  “Status check.”

  “Go Atlas.”

  “Go Centaur.”

  “Go New Horizons.”

  “T minus eighteen…”

  “… fifteen seconds…”

  “… eleven seconds…”

  At T−10 seconds the crowds began shouting the seconds along with the announcer: “four … three … two … one!…” A billow of smoke and steam shot out from the base of the rocket, and as the count dissolved to zero, a blindingly brilliant spot of light erupted at the base of the Atlas, which started to move. The light widened into an incandescent cone as the rocket accelerated and cleared the tall launch tower in under two seconds. New Horizons was in flight!

  The launch announcer marked the moment, saying, “Liftoff of NASA’s New Horizons spacecraft on a decade-long voyage to visit the planet Pluto and then beyond!”

  The behemoth Atlas was accelerating furiously upward. The flames beneath it lengthened to about twice as long as the rocket was tall, and they were unbelievably bright: even miles away it hurt your eyes to look at it. But you couldn’t look away: it was mesmerizing. A rocket was leaving on the most distant journey of exploration in the history of our species. It seemed like science fiction, but it wasn’t!

  For those there, the first few seconds of the launch had been an all-visual experience, because the sound from the event had yet to reach the crowds from the launch pad miles away. But then the rolling thunder of the Atlas swept across to the viewing sites. If you’ve been up close to the band at a really loud rock concert or under the thunder of a high-performance military air show, then you know something about what this is like, rattling your body with intense, low-frequency, staccato vibrations. Every frequency shook all at once, so that every cell of your body quivered and vibrated as the Atlas, carrying precious New Horizons, rose on a pillar of smoke higher than any mountain on Earth, and then arced, now supersonic, out over the Atlantic.

  Back at the ASOC, outside on a balcony, Alan watched alone as his baby lit up and pierced skyward, straight into the blue. He knew it was against the rules to be outside this close. But after 17 years of work, he was not going to watch this on a monitor. No one else saw the launch from so close. As the sound washed over him, louder and louder, he repeated to himself, again and again, “Go, baby, go—make us proud!” Then, when the Atlas disappeared behind clouds as it was making its gravity turn eastward, Alan sprinted back inside to join the launch team in the control center. He put his headset on, and went back to business.

  The launch team carefully monitored the rocket’s systems and trajectory, measured its performance against plan, quietly ticking off successive milestones as the launch proceeded, step-by-step, spaceward.

  After 105 seconds, the five massive solid rocket boosters of the Atlas first stage were jettisoned, having done their heavy lifting. Through binoculars you could see five little white needles tumbling and falling away as the Atlas continued to climb, its stead
y glow finally disappearing behind some high clouds. New Horizons was now out of sight, forever.

  After three minutes, the rocket was so high that it was above all air resistance, and its nose cone was jettisoned, leaving New Horizons, at the point of Atlas’s gigantic spear, out in the open. New Horizons was in space—the place for which it was built—for the very first time.

  After four and a half minutes, the first stage of the Atlas had used up its fuel and was jettisoned. The Atlas’s Centaur second stage then lit up and fired for almost five more minutes, accelerating itself, the third stage, and New Horizons to reach Earth orbit at eighteen thousand miles per hour—barely eight minutes after it left its launchpad.

  Watching the monitors in the ASOC, as the Atlas was confirmed in orbit, Alan felt a hand pat his back and the friendly voice of NASA launch director Omar Baez, “Dr. Stern, welcome to space.”

  New Horizons raced across the Atlantic, and then across North Africa, more than one hundred miles above our planet. It was spending the first hour of what would now be an eternity in space.

  Half a world away from the launch site, over the Middle East, the Centaur and New Horizons reached the mathematically calculated point at which the engines needed to fire again to boost the spacecraft onto its trajectory toward Jupiter. In the ASOC, telemetry showed the Centaur ignite again, precisely on schedule. Ten minutes later, Centaur completed its job and separated from the third stage, with New Horizons atop it. The spacecraft and its third stage were now moving fast enough to escape Earth’s gravity, yet not yet fast enough to reach Jupiter, and therefore Pluto. But 34 seconds after the Centaur separated, the Boeing third-stage STAR 48 rocket motor erupted on schedule. It only burned for 84 seconds, but it performed perfectly and accelerated New Horizons to 14 G’s and to its designed terminal speed—faster than any spacecraft had ever been launched.

  The Atlas, the Centaur, and the STAR 48 had all done their jobs. New Horizons was now screaming away from Earth, toward Jupiter.

  For Alice Bowman, back at the MOC in Maryland, the moment of truth came just seconds later, when New Horizons turned on its transmitters and APL started receiving telemetry from the spacecraft. Alice recalls, “We cheered at the launch, but not as hard as we cheered when we got that telemetry, because that’s when we knew that the spacecraft had survived launch and was doing fine. We had a mission, and that was when we popped the champagne!”

  Within only a few more minutes, tracking data revealed that the launch was an absolute bull’s-eye; the targeting was even better than prelaunch predictions. New Horizons was not only operating flawlessly, it was also right on its planned course.

  When Alan heard that report over the comm loops, he threw that dry ink pen he’d worried about into a trash can. The ASOC erupted in cheers, hugs, handshakes, and high fives across its many control rooms.

  They had done it! Against all the struggles, doubts, and naysayers of the past 17 years, a spaceship had left Earth that day on its way to explore the Pluto system. With it rode the hopes of its team and a larger scientific community for what discoveries it would make there, a decade hence, in the cold, cold reaches of the outer solar system. Also aboard New Horizons, now silently suspended in weightlessness, were some of Clyde Tombaugh’s ashes, speeding on their way to the planet he’d discovered so long before.

  A BONFIRE ON A BEACH

  That night it felt like the whole Florida Space Coast became one big joyful party for New Horizons. People were honking horns on the streets. Strangers were stopping strangers just to shake their hands. Celebrations erupted everywhere.

  The biggest post-launch party raged at a high-rise hotel on the Atlantic shore south of Cocoa Beach. By the time Alan arrived, delayed by press interviews back at the launch site, the party was already well under way, and the bar had been open for quite a while. The atmosphere was euphoric.

  That revelry went on and on into the night. Eventually, an excited crowd gathered around the smoke and glow of a fire set in a big, barrel-shaped trash can on the beach behind the hotel. The people around it were clutching beers and martinis and mai tais and margaritas, a gaggle of nerds who had something special to celebrate. Alan:

  Someone brought me over to that bonfire and told me what was up. The Atlas team had a tradition of burning all the now-obsolete emergency contingency procedures books after a successful launch. The team gave me the honor of throwing the last of them into the flames, which I did—with gusto! That Atlas team bonfire was the coolest post-launch tradition I’d seen in a long while.

  As the bonfire flames leaped above the beach and into the Florida night, New Horizons sped away from Earth at 36,000 miles per hour, so fast that it made it to the Moon’s distance ten times faster than any Apollo mission had—just nine hours after launch, and at that point, it entered interplanetary space, its new home.

  10

  TO JUPITER AND THE OCEAN OF SPACE BEYOND

  LEARNING TO FLY

  Following the excitement of launch, the crowds quickly dissipated. After a flurry of public exposure, with the launch of New Horizons featured in newspapers and television news reports and splashed across the covers of magazines, the press scattered as well. But the real work of spaceflight was just beginning for the small team of New Horizons engineers, scientists, and flight controllers charged with flying the mission across the solar system to reach Pluto.

  New Horizons, having once been merely an idea, then an underdog proposal, then a canceled mission, and then a four-year mad dash to launch, was now what it was meant to be: a flight project.

  Alice Bowman and her team dove immediately into the complex work of getting the spacecraft fully checked out and operating in space. First, they had to “de-spin” the spacecraft. When it separated from the STAR 48 third stage on January 19, it had been spinning like a dervish. This was by design, for gyroscopic stability during the solid rocket motor firing. Alan stayed in Florida for a day after the launch because he didn’t want to be in the air and out of communication until their baby passed this critical spin-down, which it did. Then he caught a flight up the east coast to APL to spend three weeks with the operations team and “live with” the spacecraft for its early phases of checkout and the first course corrections to fine-tune the trajectory toward Jupiter. In theory, Alan could have headed home at this point and consulted during the daily operations (“ops”) telecons, but he wanted the “high bandwidth” communication of being there at APL in case there were any problems that required complex resolutions.

  During the first weeks of flight, each onboard system—communications, guidance, thermal control, propulsion, and all the others—was tested thoroughly. So were all of the backup systems. This was a painstaking process that involved dozens of test procedures being sent up to the spacecraft by radio. Each test was followed by the transmission (“downlink” in spacecraft-speak) of data from the test, which the APL engineering team pored over for the slightest sign of problems or unexpected behavior.

  During these checkouts, New Horizons was already millions of miles away from Earth. Alice and her operations team were learning to fly New Horizons. Of course, they had practiced before launch, but now they were playing for keeps. So everything they did in those first weeks, every time the spacecraft was asked to do something new—turn on this system, turn on this backup system, maneuver a new way—felt to the team like it was playing with fire.

  Their major concern, of course, was that New Horizons would point away from Earth or otherwise lose its ability to communicate with them, causing them to lose the spacecraft entirely. The history of spaceflight is replete with some tragic examples of this type of accident. NASA’s Viking 1 Lander, the first successful Mars lander, had been lost six years after it touched down on the Martian surface, when a software update, meant to correct a battery-charging error, had accidentally included commands to redirect the communication dish. The errant commands pointed Viking 1’s dish antenna at the ground, where it could no longer communicate with Earth, and jus
t like that—the mission was over. Similarly, Russia’s Mars probe called Phobos 1 was lost in 1986 when a single character was missing from a software upload. This minuscule mistake caused the spacecraft to deactivate its attitude-control thrusters; as a result, its solar panels could no longer track the Sun, and the batteries lost all their power. It was never recovered. And in one of the most painful and embarrassing failures in the history of spaceflight, NASA’s Mars Climate Orbiter came in too low as it approached Mars in 1999, burning up in the atmosphere. The problem was traced to the fact that two groups of engineers had used different sets of units when computing the Mars orbit insertion maneuver: one engineering group had been using imperial units (feet and pounds), while the other group had been using metric (meters and Newtons).

  Imagine proposing and building a spacecraft and flying a mission successfully to another planet, only to die so close to its goal? These are the nightmares that cause spacecraft operators to wake up sweating in the middle of the night and to obsessively check and recheck every aspect of every plan for their birds. It’s sobering to realize, but even with a team of really smart, dedicated people, things sometimes still go fatally wrong. Fortunately for New Horizons, and the future world of 2015 that would fall in love with Pluto when New Horizons revealed it, Alice Bowman’s team operated their spacecraft flawlessly during its checkout.

  At first after launch, time had slowed down as her flight team got used to flying the spacecraft. But as they gained confidence and more and more systems checked out, and New Horizons continued to perform well, time sped back up.

  But not everything went perfectly. Barely weeks from Earth, the spacecraft-guidance-system engineer, Gabe Rogers, noticed that one pair of thrusters was firing many times more frequently than it should. The problem was traced to a design error made years before, on a single spreadsheet, that caused these thrusters to be purchased with the wrong specifications. An engineer had miscalculated the spacecraft’s mass and balance properties in that errant spreadsheet, and, unlike thousands of other calculations, this one somehow escaped all the independent engineering reviews. So now, in flight, the thrusters were having to work overtime to compensate for being underspecced, and the thrusters were firing too often. Their design life was rated for about 500,000 uses before failure, and computer models had predicted they would be used no more than about half that by the time they’d explored Pluto. But now, with this hyperactive firing, these thrusters were predicted to be used over a million times before the Pluto flyby was completed. Uh-oh.