Emily Carney is a former nuclear technician for the U.S. Navy and an accomplished space journalist. She is the manager of public engagement and social media for the Space 3.0 Foundation, founder of the popular spaceflight group Space Hipsters, and cohost of the Space and Things podcast. Bruce McCandless III is a novelist, an attorney, and the son of a shuttle astronaut. He is the author of Wonders All Around: The Incredible True Story of Astronaut Bruce McCandless II and the First Untethered Flight in Space. Their new book Star Bound: A Beginner’s Guide to the American Space Program, from Goddard’s Rockets to Goldilocks Planets and Everything in Between (Nebraska, 2025) was published this month.

Star Bound is a book for anyone who wants to learn about the American space program but isn’t sure where to start. First and foremost, it’s a history—short, sweet, and straightforward. From rocketry pioneer Robert Goddard’s primitive flight tests in 1926 through the creation of NASA, from our first steps on the moon to construction of the International Space Station and planning a trip to Mars, readers will meet the people and projects that have put the United States at the forefront of space exploration.

First Principles

How to find space—and why it’s so difficult to get there

Soon four people will feel the earth break beneath them. They’ll sweat tiny diamonds. Their stomachs will churn with exhilaration and dread as the most powerful rocket the American space agency has ever built lifts them from a Florida launchpad to begin the quarter-million-mile trip to the moon. Their journey will jump-start what NASA calls the Artemis program. On the lunar surface, these astronauts will create humanity’s first long-term settlement away from Earth, a tiny first step on what is sure to be an arduous, multi-millennia journey into the cosmos.

So why is it taking so long?

Neil Armstrong set foot on the moon half a century ago. Since then, men and women from numerous nations have spent years of combined time in space labs and shuttles, Russian rockets and Chinese capsules. The International Space Station has been orbiting Earth for over two decades. American probes have visited every planet in our solar system, many of its moons, and several of its asteroids. NASA is planning—and planning—the first human expedition to Mars. Given all these accomplishments, it may seem odd that we’re just now talking about a return to the moon and a first attempt at life on a rock other than our own.

But this is mostly a matter of perspective. Imagine Earth’s entire existence—from the beginning of the solar system to the present—as a typical twenty-four-hour day. The very first single-celled organisms show up at around 4 a.m. Life thereafter evolves in fits and starts (mostly fits) with algae appearing early in the afternoon and sexual reproduction starting up just after 6 p.m., as it still does in parts of Scandinavia. Jellyfish shimmy into view after dinner. Land plants arrive toward the end of prime time, and dinosaurs finally show up around the hour most of us are heading to bed. You get the idea. We’ve been here for a heartbeat. Humankind finally stumbles onto the historical stage a minute before midnight, scratching and squabbling and worrying about its receding hairline, which is just now saying goodbye to its eyebrows. Most of these early hominids are busy digging for grubs. A man’s gotta eat, after all. But one of the bunch can’t help herself. It’s nighttime, remember, and she’s fascinated by the lights she sees overhead, glittering like the play of sunshine on a distant dark sea. She calls her cousins over to share the view. One of them, not the smartest, perhaps, raises a hand, attempting to touch the luminous objects that seem so close . . .

Now we’re going back to the moon. It’s been several decades, true, but in archeological terms, we are still moving at breakneck speed. Which is good, because our exploration of the universe (or “space,” which is another way of saying the same thing) has barely begun. It turns out that space is big—“vastly, hugely, mind-bogglingly big,” in the words of novelist Douglas Adams. “Space is to place,” the French essayist Joseph Joubert famously posited, “as eternity is to time.” Think about that statement for a minute. The universe is so large that not even light, which travels faster than anything we know of, can make it all the way across. This is because space is not only big. It’s getting bigger.

Here’s another analogy. If our spacefaring species were living in the sixteenth century rather than the twenty-first and setting out by sail to explore the world rather than riding rockets into the solar system, we would still be inside the harbor. In fact, we could still jump from the ship and land on the dock. Even this tiny bit of progress has cost us. We have lost lives in our halting attempts to explore the heavens. We will doubtless lose more. But we’re doing it anyway—and none of our past adventures will be as difficult, dangerous, or miraculous as the one to come.

If you’re just now tuning into this effort, you’re in luck. It’s about to get good.

Our Aim

Star Bound is the story of how we got to where we are today, with some guesses as to where we’re going next. It’s an introductory text. It reeks of death and disaster. It’s intended for the general reader, assuming the general reader is a little like us: curious but not mechanically minded, intrigued by the saga of our first forays into space without knowing the mind-grinding physics behind it all. Our narrative comes complete with bias, inappropriate emphasis, and all the other shortcomings of authorial discretion. You, the reader, could find all of the information contained in this book in other sources—in some cases, many other sources.

But information without organization can be frustrating rather than illuminating. You might also find it tedious to read hyper-detailed data presented by authors who are technically literate and frighteningly intelligent. Rest assured that you will encounter no such indignities in these pages. What we’ve tried to do in Star Bound is present a coherent, if simplified, story. We hope you’ll learn a hundred things. We hope you’ll pester friends and relatives with a golden nugget you first beheld in these pages. And we hope our tale is readable in the space of around three hours—the duration of a flight from, say, Austin, Texas, to Washington DC.

If you’d like to check our sources, we can keep you busy all the way to Newark.

Defining Space

Star Bound is not an engineering text.

And that’s okay. One of the biggest hurdles to engagement with the American space program is other space enthusiasts, who can be territorial and high-handed, like self-anointed priests of a technological cult. Fact is, there’s no entrance exam for enjoying the Apollo saga or for following NASA’s plans to visit Mars. The story of space exploration is weirder and more compelling than you’ve been led to believe—a map of missed opportunities, phony promises, heart-stopping accidents, and astonishing achievements. It’s a human story, and because this is so, it’s fascinating beyond reason and beautiful beyond analysis. Don’t let the gatekeepers distract you.

Nevertheless, it’s important to understand some of the challenges involved in sending a person into space. Here, perhaps, is the first: What is “space”? There are many ways to answer this question. But for practical rather than philosophical purposes, there are two definitions, both of which involve altitude—that is, one’s distance above our planet. According to the U.S. Air Force, “space” begins at fifty miles above sea level on Earth. Another definition states that space starts at one hundred kilometers (approximately sixty-two miles) above the planet. This hundred-kilometer point is called the Kármán line, in honor of engineer and physicist Theodore von Kármán, the man who proposed it. Kármán’s is the more widely accepted delineation of where space begins, so we’ll use it in Star Bound. It’s important to have such a definition because the skies up to the boundaries of “space” can be claimed, and policed, by the countries beneath them. But above this point, space is open to travel by all. You can thank the old Soviet Union for that, as we shall see.

Not everyone agrees that either the air force measure or the Kármán line is the right boundary. Atmospheric conditions rarely arrive neatly packaged, in the way that a hundred-kilometer mark, or “line,” might suggest. The matter of where space begins is less a number than a condition. It’s the altitude at which Earth’s atmosphere has dissipated to close to nothing. Because there is so little atmosphere, there is little atmospheric “drag,” or friction, on an object traveling at this altitude. This means that such an object can no longer take advantage of the differences in air pressure between the underside of its wings and the upper side, as an airplane does, to fly. Above the Kármán line, which is the delineation we’ll use, objects travel in a way determined by orbital dynamics, the interplay of velocity, distance, and gravitational pull—specifically, in most of what we will be studying, the gravitational pull of Earth.

Sixty-two miles is not that far. If your car could travel straight upward, you could drive to space in an hour—or roughly seventeen Taylor Swift songs. But even here, not so high above the planet, the typical aspects of space are present. The gentle curve of Earth’s horizon is clearly evident. There’s not enough oxygen at this altitude to sustain human life. (This actually becomes true at a measly five miles above sea level, as anyone who has climbed Mt. Everest can attest.) It’s cold up here, but atmospheric pressure is nil, which means that your blood would literally boil in your veins if you left your spaceship without a pressure suit. The sky at this altitude is black, not blue, because there’s not enough atmosphere to diffuse the sun’s rays in such a way that we see more blue than, say, red, a phenomenon that occurs as a result of something called Rayleigh scattering. Also, people float. You may say that this is because there is no gravity to keep a person in place, but this is not true. At sixty-two miles up, Earth’s gravitational pull is still around 97 percent of what it is on the planet’s surface. In fact, weightlessness on the International Space Station or any other spacecraft in Earth orbit is the result not of reduced gravity but of another phenomenon altogether. We’ll talk about this later, when you are in a better mood.