The Interstellar Age (5 page)

One day late in the fall semester of 1985, Ed came to check in on me before leaving for the day and he casually mentioned that he was getting excited about
Voyager
’s upcoming flyby of the planet Uranus in January. He told me that, using their detailed calculations, the JPL professional celestial navigators on the team were hatching a plan that would enable a very precise flyby of the planet and its moons. Everyone felt good about being able to use the Uranian gravity to slingshot
Voyager
on to Neptune. My limb-fitting work was only a tiny piece of the planning puzzle, but still it felt good to know that I was making some contribution, however small. Then he asked—and I’ll never forget this as long as I live—if I would like him to put my name on a list to get me a special badge that would allow me to witness the encounter from JPL, from
inside the Science Operations Room.
Um, yeah. That would be great, Ed. Thanks! I did cartwheels all the way back to my dorm at sunrise the next morning.

Ed got me that badge. I still have it.

IN THE ROOM

Ed’s magic badge got me into the famous Building 264 at JPL, where the
Voyager
scientists would get their first look at these long-awaited images as they streamed in from NASA’s giant Deep Space Network radio telescopes around the world. All throughout January we could tell that
Voyager
was getting close to its target. We were all mesmerized as Uranus went from a fuzzy dot to a recognizably round and beautifully blue-green Ping-Pong ball as we approached. Now, Ed had given me the badge, but he hadn’t given me any sort of job to do. He wasn’t even around in the main science team work areas; instead, he was busy working out various last-minute issues with the camera pointing or exposure times for the flyby sequences, sequestered somewhere with a small band of critical mission planners who needed quiet spaces and uninterrupted time to do their calculations. So I was kind of an interloper, a fly on the wall, with no real reason to be there.

I tried to make myself useful in some way. Images were streaming down day and night from the spacecraft as it got closer to Uranus, and over the days leading up to
Voyager
’s closest approach the room started to fill up with planetary geologists, atmospheric scientists, space physicists, and their students and staff. I glimpsed Carl Sagan a few times but never got a chance to formally meet him, because he was usually surrounded by a gaggle of others. I met some of the grad students who were working with the images for their thesis projects, and they were like kids in a candy store. I met some other planetary scientists on the
Voyager
imaging team, such as Carolyn Porco (studying rings), Larry Soderblom (studying icy satellites),
and the late Gene Shoemaker (one of the fathers of modern planetary geology, studying everything and everyone), although no doubt they don’t remember meeting me. A few other lucky undergrads (such as Heidi Hammel) and I would hang out in the back of the science rooms and look for people who might need a coffee, or a photocopy made, or someone to run out and grab some sandwiches or meet the pizza delivery guy by the main gate. In fact, my primary contribution to the
Voyager
flyby of Uranus may have been to help keep some of the key team members from dying of starvation. I didn’t care—I was
in the room
.

There’s an interesting sociology and psychology to be witnessed when groups of people are placed together in stressful situations. Some of the people in that room had been working on this project for more than a decade, preparing intently for each of the precious few moments when the
Voyagers
would fly by their targets. The pressure would build as each person pondered the inescapable fact that there would be only one shot, one chance to get it right. Some people handle stress gracefully, while others don’t, and I saw or heard about plenty of examples of both within the inner sanctum of the
Voyager
science and operations areas as the encounter got closer.

The PI of the imaging team, a planetary astronomer from the University of Arizona named Brad Smith, was a force to be reckoned with: sometimes jovial, other times stern, and clearly—like everyone else in the room—worried about it all going well. He kicked us interlopers out several times, for special “team members only” meetings or just because he thought there were too many people in the way. Sometimes he was nice about it; sometimes he wasn’t. My former Cornell University colleague and research mentor Joe Veverka, a member of Brad Smith’s
Voyager
imaging team, tells a
story about how, at an early team meeting, Brad had everyone shake hands and apologize to one another in advance for the nasty things they were probably going to say and do in the heat of the upcoming stressful flybys. Joe would later give the same advice to the imaging team that he led on NASA’s Near Earth Asteroid Rendezvous mission, and as a member of that team I can vouch for Joe’s (and Brad’s) sage advice.

I would see Project Scientist Ed Stone, who seemed to me, from the back of the room, to have that gracious and kingly sort of personality, make little speeches now and then to encourage the team, or intervene and occasionally break up some of the somewhat-too-heated debates that would pop up among the tired and overworked instrument teams. I asked Ed how he kept his cool during those stressful, exciting days.

“I don’t know!” he said. “It was just such a great thing. There was so much hard work; there were discoveries every day. It was just incredible. And wonderful.”

I had to conclude that Ed must have just had the right genetic disposition to lead a group of talented and highly motivated people through such stressful experiences
.
My friend and colleague Ann Harch, who was a
Voyager
sequencer and the science operations coordinator during the Uranus and Neptune flybys, says that she and others viewed Ed Stone as an incredibly fair and approachable leader. “He did an amazing job of making sure that
all
of the science investigations got their important science into the plan,” she recalls.

The Uranus flyby itself, on January 24, 1986, went stunningly well (much better than the Super Bowl a few days later, in which, sadly, my Patriots got crushed by the Bears 46–10). Uranus itself was fairly bland, showing no evidence of the stunning clouds and
storms like Jupiter and Saturn. It was the Uranian moons that stole the show—tiny, icy worlds with staggeringly high cliffs and cracks and super-dark plains interspersed with bright (icy?) cratered debris. Uranus is tilted on its side (rolling around the solar system instead of spinning), and so its dark rings and five large moons make for a sort of bull’s-eye dartboard pattern that
Voyager
was aiming for. The spacecraft passed through the bull’s-eye close to the tiny, jumbled-up moon Miranda just before making its closest approach to Uranus. Images streamed in nonstop. A few of them would later make their way into newspapers or onto the network news, but those of us there at JPL were the fortunate ones who got to experience, live, our first encounter with these exotic worlds.

And then, just like that, Uranus was in the rearview mirror. We watched the blue-green world that we’d been seeing head-on for weeks wane into a thin, ghostly crescent as we passed behind it. The planet’s rings were revealed in all their glory by looking back at them, into the sun, making their tiny particles light up for the cameras like a wet or frosty windshield lights up when you’re driving into the sunlight. Many team members started to pack up to head back to their homes, with data tapes and stacks of photos in hand and dreams of discoveries to make and scientific papers to write.

Ed Stone and other
Voyager
team leaders began to prepare for a NASA press conference in which they would share the “greatest hits” from the Uranus flyby—stunning images and other measurements of the planet, moons, and rings, as well as initial results about the planet’s magnetic field and its interactions with the solar wind. Ed Stone thought it would be a wonderful celebration of one of the greatest achievements to date of the space age—the first encounter with a new world.

But the celebratory mood and all that press-conference planning stopped suddenly on the morning of January 28, when the Space Shuttle
Challenger
exploded just seventy-three seconds after launch, killing all seven crew members. I remember it vividly, watching on TV from my college dorm room. I never missed a shuttle launch on TV, and I was even lucky enough once to hop in a car with a bunch of college friends at the last minute and catch a shuttle landing at Edwards Air Force Base in the Southern California desert. Seeing
Challenger
explode live on TV was jarring, not just for me but for my
Voyager
colleagues, everyone else involved in the space program, and the nation as a whole. Management and design flaws in the shuttle system were uncovered, and it forced major debate and soul-searching about the importance of human space exploration for America’s future. The media became instantly consumed by the
Challenger
disaster, fleeing Pasadena in droves and leaving the rest of the
Voyager
Uranus story untold. Ed Stone and the rest of the project leaders knew they had to postpone their press conference. The “greatest hits” made it out there, eventually, but they were released without as much fanfare. The remaining somber team members slowly drifted off and headed back home.

A few weeks later, back on campus, I finally had a chance to see Ed Danielson again for more than a fleeting hello. He had been working hard as an imaging team liaison to the JPL navigation team to figure out how much
Voyager
’s trajectory had been bent (ever so slightly, but measurably) by the gravity of Uranus and its moons. This would enable the navigation team to estimate the mass of the moons, which, when combined with estimates of the moons’ volume from the images themselves, would let the team estimate their densities. The moons turned out to have very low densities, close to that of water ice.
Perhaps not surprising, given their location in the cold outer reaches of the solar system, but still, Ed wanted to get the numbers right. I tried to express the depth of my gratitude for getting me that badge.

“It was nothing,” he said.

After graduation, Ed and I stayed in contact, catching up at various conferences or during my occasional trips back to Caltech. He took a leading role in the development of the first high-resolution planetary camera, the Mars Orbiter Camera (MOC) on the
Mars Observer
mission. Unfortunately, that spacecraft, and Ed’s darling camera, blew up just three days before getting to Mars. Undaunted (“It was nothing”), Ed and his MOC teammates from Malin Space Science Systems in San Diego built another one a few years later for the
Mars Global Surveyor
mission, and
that
MOC got to Mars safely and went on to discover gullies and deltas and massive sedimentary layers—photos of which would forever change our perception of
that
world as well.

Ed retired in 2004 and, after battling
complications of a stroke, passed away in late 2005. I still feel his influence on me every day. Using the skills Ed taught me as we pored over those early
Voyager
Saturn images in his workroom, I was later able to work on a project of my own, mapping the geology of Miranda and the other moons of Uranus. I also developed a sense of the important role that hardworking scientists like Ed Danielson and Ed Stone can play behind the scenes in the enterprise of space exploration. The grunt work of science—planning the observations, calibrating the images, processing the data, making the mosaics, training the newbies, balancing the budgets, and so on—is critical for the team to
get it right.
Missions like
Voyager
succeed because of people like them. This world needs its tinkerers as much as it needs its
theoreticians.

2

Gravity Assist

A
S A KID
launching model rockets in my backyard, spending hours carefully gluing parts together, applying stickers, painting the fuselage, packing the parachute, and installing the engine, I would wonder,
Did I balance it right so it will launch and fly straight?
Most times it did, but sometimes it never got off the pad or launched sideways, causing me and my sisters to run for safety.
How far will it fly?
Sometimes completely out of sight, never to be found, maybe swallowed up by the trees . . .
Can I figure out how to mount a small film camera to the nose cone?
I never did, too heavy . . . Repairs or rebuilds had to be done, then another long lead-up to the launch, and then another suspenseful countdown as family and friends stood by—often watching from indoors to stay safe.

It turns out that many of the problems that need to be solved to
launch model rockets are the same kinds of problems that engineers and scientists involved in NASA space missions have been working to figure out since the 1960s. How do you design the craft to withstand the stresses of launch and the harsh cold vacuum of deep space? How do you figure out how to communicate with it and control it once it’s out there? How do you get pictures and other measurements sent back from it? How do you design its mission? Early on, there was another question that arose once we started thinking about space travel: can we use a planet’s gravity to speed up and turn a corner? That could enable our rockets, our spacecraft, to go even farther. . . .

Even though it’s a cliché, lots of times a space mission really
does
start with scribbles on the back of a cocktail napkin. Or with conversations among colleagues over beers after a day at a professional conference. Or sometimes the idea comes in a dream, or in a flash of realization akin to making a discovery. Indeed, the
Voyager
mission appears to have begun in such a flash of inspiration.

In the mid-1960s, Gary Flandro was a graduate student in aeronautics at Caltech studying instabilities in rocket combustion and working part-time at JPL helping to study the aerodynamics and trajectories of missiles. His supervisor was one of the key members of the JPL Mission Analysis Group that was working to devise the upcoming
Mariner 10
Venus–Mercury gravity-assist flyby mission, and he suggested to Gary that he help explore the possibility of similar gravity-assist trajectories being used for outer solar system missions. It was an area that almost no one else was looking into yet at JPL, as the lab was focused almost exclusively at the time on lunar, Mars, and Venus mission work.