by Bill Nye
Along with the constraints of having to keep the area suitable for business, maintain or improve livability, and make use of existing highways and streets, the architects also had a lot of information to guide them. The data on damage caused by Superstorm Sandy are detailed and stark. These engineers have a pretty good idea of what can go wrong. The rebuilt waterfront neighborhoods have been designed to function normally almost all the time, but when a big storm arrives, the revised shoreline must absorb the floods. The next giant storm should leave the area largely intact and completely livable. There will still be plenty to clean up—when an urban flood subsides, it leaves behind a lot of trash and other unpleasantness—but city planners believe the neighborhoods and subway trains will be in much better shape than they were after Sandy.
Money is another constraint, of course. The cost of the Manhattan waterfront-rebuilding project is estimated at $335 million, according to Bjarke Ingels. That may seem like a lot of coin, but it’s about 1⁄200th of what Sandy cost the city in lost business and damaged infrastructure. The Big U will be well worth it, if it works as planned.
Most of the time we have no difficulty identifying the problem we want to solve. The hard part is figuring out why the problem is a problem at all. Defining that cause then clarifies the constraint and makes the whole thing easier to solve. In the case of my ellipse, the cause was that I didn’t understand rotated coordinate systems. If you look and see that your basement is flooded, for instance, there are many different possible underlying causes. Is it that the drainage is inadequate and you need to install a pump? Is it that the previous owners failed to seal the walls on the east side of your house? Or is it that climate change is bringing on too much rain every year, and this is no longer a sustainable place to live?
This is where outside expertise—the nerd collective—becomes indispensable. In my math class, I didn’t have to look far; Mr. Lang played the role of the informed outsider. In the case of my hypothetical basement flood, I would assess the cause as well as I could, but then I’d probably call on people with complementary knowledge. I might even need to go through a sequence of expertise, from plumber to building engineer to environmental scientist, before I had adequately defined the cause and isolated my helpful constraint. Calling on the experts does not reduce your control of the situation; it increases it. I feel like a lot of people misunderstand this point when they complain about the “experts” telling them what to do. Experts help you constrain the problem and move forward. Without them, you can still do something—but there’s a very good chance it will not be the right thing.
When I’m not in New York, I’m generally in Los Angeles working at my job as the CEO of The Planetary Society. The expertise around me there—just wow. My colleagues had to convince me I could do the job, and sometimes I still can’t believe I’m the guy in charge (see Chapter 21 for more on that). The Planetary Society is the largest public organization supporting and advocating for space exploration. As the head guy, I do my best to guide space policies all over Earth toward the goal of finding evidence of life on another world. I feel strongly that such a discovery would be among the most profound events in human history. But to most legislators, regardless of nation, sending robots to drill for microbes on Mars sounds like a distinct luxury—and a costly one at that. Reconciling these two perspectives is a case study in another type of constraint.
Sometimes the biggest constraint we face is how to get attention for the problems that we want to solve, especially when our solutions require time, money, effort, and/or attention. There was a time when geopolitics alone was enough to drive such exploration. The Apollo voyages to the Moon were made for the sake of winning the Cold War; they never would have happened without the US and the USSR competing for superiority. Those of us who believe deeply in the value of space exploration have to sell it in new ways to overcome the modern political constraints. We have to think rigorously about what’s important in space and about the benefits here on Earth.
A big part of succeeding as a nerd is figuring out how to tell a story about a problem in a way that gets others excited about being part of the solution. For instance, I strongly believe that space exploration brings out the best in humankind: We achieve mighty things when we venture above the atmosphere and send our best instruments, designed by our best scientists and engineers, to make discoveries around and upon other worlds. We are at our greatest when we push against the greatest constraints.
There’s education, for one thing. Space exploration is a potent motivator that helps draw kids into science and technology. The US Department of Education spends nearly $80 billion every year. For comparison, NASA’s planetary science budget is about $1.5 billion—about 1⁄50th as much. Ask yourself: Which one excites more young students and inspires them to tackle the hard work of calculus and Advanced Placement physics and chemistry?
There’s also technology. Here I’m talking not just about the spinoff inventions from NASA and NASA-related programs, although they are numerous, from fuel cells to digital cameras. Consider the much broader value of the World Wide Web, weather forecasting, and the global positioning system. But far, far more significant for me is that space exploration is how we learn more about ourselves and our place in space. By exploring worlds beyond our own, we solve problems that have never been solved before. And when we get used to solving problems that have never been solved before, the world becomes a better place. Space exploration has created a culture of innovation that affects everyone on Earth every day.
You might notice that there’s a feedback loop of constraints at work here. Dealing with the technological constraints of launching space probes to other planets forces engineers to be extremely creative; that creativity, in turn, helps address the political constraints that often prevent such missions from getting funded in the first place. All along the way, enlisting nerds to work on problems of space exploration yields all kinds of secondary benefits to society. It strengthens the entire chain of expertise. Very crafty. Very everything-all-at-once.
The battle against constraints can seem exciting and inspirational when we’re talking about high-minded space exploration, but it’s a different story when the conversation turns to practical concerns. Even a focused project like New York’s Big U took a great deal of unglamorous negotiating and cajoling. When it comes to bigger challenges, constraints tend to lead people to despair, pessimism, and inaction. It’s all too easy to fixate on the paths that are cut off from us and think that there is no way forward at all. From there, it’s a short journey to denial, or to a nostalgic yearning for an earlier time when our problems seemed less difficult.
If you know me at all—and by this point in the book, I’d bet you do—you can probably guess that when I think about progress in one area, I’m thinking about how it applies in other areas and disciplines, as well. And I’m always thinking here about our rapidly warming world and our rapidly changing climate. A large number of people today believe, or say they believe, that climate change is not really happening. There are politicians and business leaders who claim we’d be better off if we tracked backward toward the age of coal and oil. They find the constraints of our energy future too scary to contemplate. But I am confident that this crisis of confidence will pass. We have overcome many similar crises in the past.
Space exploration forces scientists and engineers to expand their thinking because of the extreme nature of those constraints. For protecting Manhattan’s waterfront from future storms, the constraints were set by practical considerations such as cargo transport and pedestrian access. For the kinds of missions championed and funded by The Planetary Society, the constraints are utterly impractical, sometimes comically so. A project might begin with a brainstorming session along these lines: “Okay, everyone, you have to land a car on Mars. Let’s go!” This is no made-up example. It’s the very problem that NASA had to deal with in creating the Curiosity rover that is currently rolling across Mars, and will deal with again at the end o
f the decade when the agency sends an even more advanced rover, currently called Mars 2020. Both rovers are about the size and mass of a Chevrolet Spark automobile. So how are they going to do it?
If you have the naïve confidence of a budding engineer, you might think, “It can’t be all that hard. We just have to slow down enough to roll or skid to a stop. We land airplanes all over the place every day. We landed all sorts of things on the Moon. Surely we’ve got the basics of that figured out by now.” In other words, you’d start with the problem you know, just like I started out trying to solve the ellipse using the math I’d already learned. But it turns out that this business of setting down intact on the surface of Mars is some kinda crazy complicated. On Earth you have a lot of air to work with, and even the fastest fighter jets are dealing with much, much lower speeds. When the probe carrying the Curiosity rover approached Mars, it was moving at more than six times as fast as an F-35, with the throttle to the firewall—going all-out. That’s a lot of energy to dissipate.
Over the years, the creative engineers at NASA designed a few lovely retrorocket systems. Just as in an old Flash Gordon serial, the 1970s Viking landers lowered themselves tail-first onto the surface of Mars, retrorockets flaming beneath them (I mean, dude, those rockets were, like totally retro—uh, sorry . . .). As cool as they are, retrorockets are not an affordable option for gently landing a rover, however. Rockets kick up a lot of dust, which could damage sensitive instruments and moving parts. They also blow out a small crater where the blast hits the ground; getting out of that crater could present problems for the rover just as it’s getting started. And all that fuel and the gizmos to steer the exhaust are heavy. So much for familiar solution #1.
On to #2, using the atmosphere to slow you down. The two Viking landers had heat shields that dragged through the atmosphere, scrubbing off some of their deep-space velocity so the retrorockets didn’t have to work as hard. If a heat shield can slow things down a little, then a parachute should slow things down a lot, right? Ah, but this is where the in-betweenness of Mars messes with you again. It turns out that the Martian atmosphere is much too thin for regular Earth-style wings and parachutes. The atmospheric pressure on Mars is 0.7 percent of the pressure here. There just aren’t that many air molecules for a parachute to catch hold of. Furthermore, an incoming spacecraft and its parachute will be going faster than the speed of sound in the upper Martian atmosphere. Entering at supersonic speeds sets up pressure changes and shock waves that can make a parachute rip itself apart. It would be a sonic boom of death.
So there was no existing piece of technology that would accomplish the job at hand. The engineers at NASA’s Jet Propulsion Lab in Pasadena had to tilt their heads and look at the problem in a different way. The constraints of the unprecedented conditions and existing technology forced them to create something that had never been created before, mixing the old with something completely new. They identified the problem, zeroed in on the causes of the problem, blended expertise, and achieved beautiful progress. They drew on ideas not just from earlier space missions but also from military jet research and from automobile safety testing. You can see why the constraints of space travel are so constructive.
A breakthrough came when the engineers realized that they didn’t have to get the spacecraft to a complete standstill; all they had to do was make sure the landing was gentle enough to survive. They started with a “cap and ring slot” supersonic parachute to slow things down a bit, followed by a retrorocket phase to slow things some more, and finally a landing phase aided by . . . four big balloons (talk about old technology). No kidding. Right before hitting the ground, the capsules holding the Mars rovers puffed up with four super-tough airbags. They freely fell the last several meters and bounced more than a dozen times along the equivalent of a few football fields over the red dusty surface before deflating and opening up so that the rover tucked inside could drive away. NASA put three rovers, Sojourner, Spirit, and Opportunity, on Mars that way, with spectacular success.
The fourth rover, Curiosity, was considerably bigger and more capable than the ones sent before. With more weight came a new set of constraints. Airbags would not be enough. Now the engineers had to tilt their heads again, and they emerged from their brainstorming session with an even kookier solution. Their insight this time was that retrorockets are okay as long as they don’t get close enough to the ground to kick up big clouds of Mars dust. Their solution: Start out by slowing way down using a specially vented supersonic parachute. Then, fire retrorockets, but don’t let the exhaust nozzles get too close to the surface. Next, lower Curiosity from the underside of an eight-rocket jetpack, which the engineers call the “Sky Crane.” Have the Sky Crane fire its retrorockets, bringing the whole package to a near-standstill, suspended about 20 meters (60 feet) above the Martian surface for a few seconds. Then the one-ton rover could rapidly rappel down three nylon ropes, like an Army Ranger descending from a battlefield helicopter. Once the rover is safely on the ground, the ropes would detach, and the Sky Crane would blast off again, flying away to a safe distance before crash landing. Hard to believe, but this system worked beautifully, too.
While we’re on Mars—no, wait, we’re still on Earth. I mean while we’re on the subject of being on Mars, we must contemplate what we would need to do to put humans there. For a crewed mission, landing a one-ton payload will not be nearly enough. We’ll be trying to deliver dozens of tons, maybe 30 or 40 tons, at a time. We will need to send enough equipment to build a full life-support system and backup systems, complete with protection from radiation and from the harsh Mars environment. We will need to send food and medical supplies. All this on top of the scientific equipment needed to study the planet and to search for Mars microbes (Marsrobes?), whether living or fossil. We’d have to look at those constraints and conclude that sending astronauts makes sense even after we take them all into consideration.
That’s a whole new set of constraints to overcome, by far the most difficult ones yet. It’s like the earlier question about landing a car on Mars but a whole lot more so. Right now, there is no conclusive answer. Engineers at NASA and at SpaceX, the company run by Elon Musk of Tesla fame, are still tilting their heads at the problem, but they have a promising concept. Since parachutes and retrorockets both have limitations, they thought, how about a system that combines the best aspects of both? The system they have in mind would shoot retrorockets at just the right angle and at just the right velocity to act like a gigantic virtual parachute in the thin Martian air. Testing this concept will be hugely challenging. High-altitude rocket experiments on Earth are the best nearby approximation we’ve got. Ultimately, it will take a real landing on Mars to prove it would work. If they succeed, it will be the result of the same lessons I absorbed back in high school. Knowing which approaches can’t work makes it easier to find the ones that can. If they fail, that will feed new constraints into the next effort.
I bring this all up to make a point about the process of creating progress. Each of the designs I’ve discussed here—airbags, the Sky Crane, the retrorocket parachute—adds to the tool kit for space exploration. Each constraint inspires a new solution to draw on for the future. I am confident that someday we will land probes on other intriguing worlds, including Jupiter’s ocean moon Europa and Saturn’s moon Titan, which is dotted with lakes of liquid methane and ethane. When that happens, engineers will make use of that tool kit. If none of the existing solutions are quite right, they’ll just tilt their heads again. And every bit of the increasing collective expertise will help in overcoming constraints on Earth, as well.
Less than a century ago, people worried that smallpox was unbeatable and would eventually kill every human on Earth. In the 1790s, and again in my lifetime in the 1960s, many people thought that population growth would overwhelm our ability to produce enough food, leading to widespread starvation. Strange as it might seem now, many people thought that the year 2000 computer-clock problem (Y2K) would bring our society to a
standstill—and maybe it would have if engineers had not hustled and addressed the problem in every computing machine they could find. It was not a magic spell that kept Y2K from being big trouble; it was diligence and attention to detail on a big scale.
Climate change is a bigger challenge than any single problem we’ve faced before. I hope it inspires more creativity and more dedication than ever before, becoming part of the nature of progress. As our ambitions become greater, so do the constraints we must deal with. Then those constraints drive us to tilt our heads and find new, bigger, more creative solutions. That’s true for each of us as individuals, and that’s true for society as a whole. But we cannot afford to stop, or even to slow down. We need to meet our constraints as they confront us.
As soon as the going gets tough, I am confident that tough people will get going. Soon, other coastal cities will have to start rebuilding their waterfronts just as New York City is doing. That work is starting to happen as a reaction to devastating natural disasters that are landing all over the world. As soon as the first floors in Norfolk, Pensacola, Galveston, and Miami are ankle-deep with a few centimeters of water day and night, people will take all this seriously. They will be able to draw on engineering work pioneered in New York and other early-reacting cities. But just think about what kind of damage and tragedy we could prevent if we started solving the problems before they happen. From a scientific and engineering point of view, we can see them coming clearly, and we have more than enough information and evidence to anticipate the constraints that will need to be addressed.
Instead of running in circles, waving our arms—or, worse, going about our business in willful ignorance—we could get to work now. We could erect wind turbines off the east coast of the United States, Canada, and Mexico. We could install photovoltaic panels practically everywhere the Sun shines. We could heat and cool a lot of our dwellings, offices, and factories using geothermal sources. We’d create jobs, boost the economy, clean the air, and address climate change. If you really want to make America great (and the rest of the world, too), these are the main things you, I mean we, need to do. It sounds like an enormous undertaking, and it is, but as we’ve seen again and again, the enormous ones begin with small perceptual shifts.
