Update 18 June 2024: As discussed in the comments, a reader pointed out that I was misinterpreting the indication of the month of the year, and Lego’s instructions are correct. I’ve struck out the incorrect portions of this post. (And I’ve corrected the model on my desk.)
When I saw that Lego was releasing an orrery, I knew that I had to get my hands on it — for work! I deal with new space mission concepts around the Moon with some regularity, and you have no idea how often I find myself thinking, okay, that lamp is the Sun and my hat is the Earth, so the spacecraft has to point its solar panels over there — but then the Earth moves, so it has to point over there now…. A functional desk orrery would actually come in handy! Well, I’ve finally purchased and built Lego set #42179: Planet Earth and Moon in Orbit.
Here’s what I think of the model and how well it captures the real motions of the Sun-Earth-Moon system.
My job is to explore space. The work I do, day to day, involves figuring out how to get space probes to exotic parts of our Solar System, so that scientists can investigate the inner workings of the planets and flesh out their understanding of humans’ place in it.
One of the strangest things to me about my job is that I agree with almost none of the reasons popular in space media for why this is an important and worthwhile endeavor. National prestige? No, I would be happy to work with scientists who aren’t funded by the US government. Finding resources in space for us to exploit on Earth? Nope, not only is that not what science is doing but I think it would be ultimately unproductive. Inspiring the next generation to pursue STEM careers and fill a supposed “STEM gap?” Heck no — I was inspired to study STEM in order to explore space, not to help a tech company sell surveillance or to fill up jobs in the military-industrial complex.
I explore space, I want to explore space, because I want to be part of something greater than myself. I want my work to help build a monument of scientific achievement that will stand for generations. I want to reach, to dream, to aspire, to learn, and to create. I want to explore space for the same reasons an artist or a poet wants to do what they do.
I think people in my field are afraid to say that. The reason is, I suspect, because we fear the obvious rejoinder: why are you wasting time and resources on that when we have so many problems to solve here on Earth?
My answer has been that it’s not a binary choice: We can feed the hungry, and have poets. We can heal the sick, and have art. We can make a better life for people on Earth, and explore space. But more than that, I think it is part of the measure of a society what we aspire to do and create for tomorrow, not just how we react to the events of yesterday. That’s why I explore space, and why I think it’s important that we — our nation, our society — continue to explore space.
But looking back over the last few years, I have a problem.
I have been completely caught off guard, emotionally and intellectually, by the approach my society is actually taking.
We faced a national disaster in the form of the COVID-19 pandemic, and we collectively decided, nah, we’re just not going to bother to do anything about this. A million people died as a result, most of them easily preventable deaths.
The looming crisis of catastrophic climate change is turning into a global disaster before our eyes, with wildfires, heat waves, hurricanes, floods, and other events rapidly racking up body counts and property damage, threatening our way of life in the near future with everything from decreased production to reduced military effectiveness to food shortages to logistical challenges that will dwarf anything we saw in 2020, and we collectively decided, well, I guess you’ve just got to get what you can while you can. So much for the next generation.
Inequity is a scourge on our national economic effectiveness, not to mention inhumane to those experiencing it, and we have collectively decided, if the worst-off among us have no bread to eat, then it’s on them to find cake. Just so long as the rest of us can’t see them.
Madmen enter our schools with devices designed to make human bodies explode, kill innocent children and young adults, and our society has decided, oh, well, too bad, and we hold a moment of silence while we wait for the next one to happen. Meanwhile, we traumatize kids with intrusive security measures and drills that will remain ineffective so long as we keep fetishizing access to violence. The recurring Onion headline is so biting because it is an exact measure of the depth of our failure.
We are, to put it simply, no longer a nation that tries to solve its problems at all. What solution-oriented programs we have continue only on inertia, not because we are trying to improve the parts of our society that need attention. What aspirational efforts we have also seem to continue on inertia, not because of a national drive to be better. So here I am, attached to a vestigial aspirational effort and arguing that we could do both while our society around me is deciding to do neither.
We got here because one of America’s major political parties has spent decades pushing a message that boils down to the insistence that government should not solve problems, or heck, government should not do anything except for a few legacy activities that benefit the relatively privileged. As a result, we have built a system where we don’t help the sick, we don’t help the poor, we don’t plan for the future, we don’t create opportunities, we don’t innovate, we don’t address the root causes of crime or oppression, we don’t educate our kids, we don’t even keep our kids safe from harm. And these things seem to have become our national values, so that enough voters feel a patriotic and political obligation to continue not solving the problems that face all of us. Now, only those of us who started with money have a chance.
I fear for the future because we live in a nation where that same party can win most state and federal representation with less than half the vote, is actively working to secure power regardless of future vote outcomes, and is willing to deploy violence and intimidation if it doesn’t get its way. For a brief window, though, we have a chance to ask ourselves: Is this really the kind of society we want to be? We really want to be the society who rearranges deck chairs on the Titanic, because oh, well, this is what being ‘Merican is, and we don’t want to see the iceberg so we just won’t?
It didn’t used to be.
I wish we could aspire again.
I wish we could solve basic national problems again.
The fact that we have collectively decided not to is so frustrating to me because it cuts right to my self-image.
The only thing I know of to do in response is vote for Democrats, and press them to safeguard our democracy.
The Cathedral Galaxy setting is now complete with a full set of regional maps, each highlighting a particular area of the galaxy and an aspect of the setting. Extra lore and artwork are scattered throughout, in addition to the larger overview map and establishing descriptions of each region posted here. Enjoy!
My next step is writing a story in this galaxy. I will not make any statements on how long that will take!
In addition, I’ve had a few people ask me about setting role-playing games in the Cathedral Galaxy. That idea intrigues me, and I’m happy to learn that players are interested in using my universe for their games. So, I have put together some lore and gameplay reference materials that you may use. Click through to read more.
The Cathedral Galaxy: so named to evoke an awe-inspiring structure; something built over generations. Eons before the advent of starflight, the Ancients – Progenitors, Precursors, Archaics, Elders – constructed a galaxy-spanning civilization. They learned to harness energies, manipulate matter, and gather information on a vast scale, ultimately building a network of wormhole passages across the galaxy. At the height of their power, they encountered a malevolence from outside the galaxy: some think an evil intent, some say a natural phenomenon. Nobody yet knows what happened to the Old Ones. Perhaps they died. Perhaps they absconded. Perhaps their essence remains embedded in the constructs they left scattered through the galaxy – some still functioning at mysterious purposes, some long torn down by the forces of gravity and radiation. Perhaps the Elders even remain alive. After all, ages after empires have risen and fell and risen again, no one has penetrated the dense, irradiated Cathedral at the galaxy’s heart.
The Cathedral Galaxy map
Thousands of years ago, the first modern peoples discovered the principles of spatial trajection. With this starflight capability, a ship could disappear from normal space and, a fixed time interval later, reappear some light-years away. They soon found ruins of the Prior civilization. Eventually they located the Founders’ great Anchors, entry points to the wormhole network, providing instant transit – much better than time-consuming and energy-intensive trajector jumps. Many other peoples followed suit, and the wormhole passages thus became channels of commerce and information allowing galactic civilizations to be built again. Through their history, the peoples of the galaxy have always been keenly aware of those who came before – and all that has been lost, exemplified by the nonfunctional wormhole gates drifting near many of the active Anchors. Now, the galaxy has reached a relatively stable state. Decadent empires, considered republics, brave adventurers, learned researchers, inventive scavengers, and noble warriors make their home in this galaxy, from the populous core nations to the empty frontier fringes.
It is a galaxy of both promise and stillness at this moment in time. After eons, what is an extra nova in the uninhabited core? What is a rumor of new Anchors opening, or existing Anchors closing, but a rumor? And what is an archaic megastructure activating instruments, seeming to seek for something outside the confines of the galaxy, but a relic running an obsolete program…?
Original line art
I have been mulling an improved map of the Cathedral Galaxy for some time, and finally bit the bullet. (Here’s the original.) For this improved and expanded version, my method was to draw the line art in black pen on white paper, then invert a photograph and color/manipulate it in Photoshop. I’m pleased with the result.
Amseile, a proud young realm nestled in two star-forming nebula regions. After uniting from several independent systems in 18k450, Amseile fought a devastating war with Shobah with lasting effects on galactic politics to this day.
The Axiom Republic, a large, baroque state of learning and cultural achievement. The Republic’s central location in the galaxy means that it contains many Precursor artifacts such as the Spire and Taron’s Throne, as well as celestial phenomena like the emission nebula Twin Idols, dust clouds of Onyx Space and Silver Run, the active Sapphire cluster, and the end-of-life star Khalkeus that sheds heavy elements.
Harrow’s Core, home of two enigmatic peoples who believe, among other strange ideas, that the galaxy itself is a living organism. There are rumors that a secret and powerful Archaic weapon prevented other polities from absorbing the Core during their expansionary phases.
The realms of what the core nations call the Exiles, nearly cut off from the rest of the galactic network by a quirk of the arrangement of wormhole passages: Babylon, a decadent theocratic empire; the Free Worlds, a xenophobic and militant confederation; and the Underworlds, domain of a people stereotyped by the rest of the galaxy as the Dead Ones – according to one legend, the last of the Ancients, but robbed of their faculties. The Panther Nebula, a dust cloud with an obviously recognizable shape from throughout the Burial Grounds, signals adventurers away from this region.
The Far Reaches, a spiral arm of the galaxy with a sparse population but many lesser Elder relics.
The Imperium of the Triumvirate, once a vast empire, now reduced to three closely allied provinces each under its own despot: technologically advanced, aggressive, and lacking restraint. The Imperium’s skirmishes are not always with other nations. Aoreu is known for the exotic star-forming Menagerie, but the true symbol of the Imperium is the Coliseum, a Progenitor-built sphere surrounding a white dwarf, where biomechanically modified beings battle for citizens’ amusement.
The Mariner Worlds, a loose affiliation of wanderers, not all native to this sparse region or even to the galaxy itself. Among these worlds are Harbor, a focusing construct partially surrounding an unusual dwarf star that appears on the verge of collapse to a neutron star; Haven, a resource-rich protoplanetary disk; and the Lighthouse, an array of transmitters and instruments aimed into the extragalactic medium.
Shobah, a nation of rigid structures and protocols, home to a sect of Librarians who believe that the Ancients discovered all knowledge it is possible to find, and therefore focus all research on the ruins scattered throughout the galaxy. Knowledge gleaned from the Ancient wrecks helped Shobah fight off Amseile’s incursions in the war.
The Traders’ Rim, where the layout and performance of the Channel Anchors make the region vital for speeding commerce and communication among the central galactic states from the Imperium to Shobah. Traders are some of the few people grudgingly accepted into the Free Worlds, making them a tenuous link between that region and the inner galaxy. Prominent landmarks in the Rim include the blue giant Azure, the black hole Point of No Return, and the planetary nebula Mokid’s Eye.
The Ramparts, filled not only with ancient artifacts from the First Ones, but also with the remains of several civilizations that died out before contact with others.
The Sea of Relics, a span with a high proportion of Elder artifacts – many of them still functioning, such as the cryptic information repository at Bastion. Radiation from the active jets of The Pillar keep this region relatively uninhabited. The Burial Grounds, on the other hand, collects fragmented wrecks of Archaic constructs after gravitational tides and cosmic radiation have weathered and broken them down.
The Well of Ghosts, a devastated region scattered with burned worlds and detritus from the Amseile-Shobah wars. It stands as a monument to the terrible power of starflyers’ weapons.
Not all peoples of the galaxy are rooted to a location. The Waygehn had the misfortune of evolving close to the end of their star’s life, and are now spread throughout the Axiom Republic, Traders’ Rim, Imperium of the Triumvirate, and Amseile to form their own political super-entity. Many Waygehn located functional-but-inert relics and retrofitted their own systems onto the ancient hardware to form great arkships and wandering space stations.
Neil Armstrong, in the LM after his historic lunar EVA with Buzz Aldrin
As I write this, it is 50 years to the moment after the Lunar Module Eagle ascended from the surface of the Moon, carrying a victorious Neil Armstrong and Buzz Aldrin up to their rendezvous with crewmate Mike Collins in the Command Module Columbia. Although I am too young to have personal memories of this event, I’ve been following the mission on its 50th anniversary through the web site Apollo in Real Time. It’s been exciting, and I, like many others involved in the space industry, have been driven introspective.
Why did we send Apollo 11 to the Moon, and why should we keep sending people to explore space?
The first question is all about geopolitics. The United States sent Apollo 11 to land on the Moon because the country wanted a very public way to demonstrate the superiority of its technical capabilities over the Soviet Union. The deep political worry at the time was that the USSR would not only beat the US to the Moon, but that they would emplace weapons there that the US could not counter-target — messing up the strike and counter-strike strategies underlying the insanity of mutually assured destruction. So, the US also decided to conduct its lunar landing in a way that would establish a specific set of norms for space exploration activities: We do this on behalf of all the people of Earth. We are here for science and knowledge. We show the world everything we do, as we do it. We come in peace, for all mankind. Apollo 11 literally left a model of an olive branch on the Moon.
But now the race is long over, and the norms established are taken for granted (if we remember them). Why continue? I find this a difficult question for me to answer — partly because I don’t believe several of the common arguments to be very compelling. Those arguments are science, spinoff technology, and inspiration.
Science is the easiest to dispense: our robotic probes reach across the Solar System, relaying extensive data back to scientists on Earth. The time, effort, and expense of sending a human mission to, say, Mars, absolutely dwarfs the cost of a robotic science mission. As an example, a recent report estimated the cost of a 2037 Mars mission as $120 billion (not including some other significant developments like a precursor lunar landing); the NASA Science Mission Directorate puts a cost cap of about $600 million on Discovery-class missions like the InSight lander, meaning we could send 200 robotic missions for the cost of one human mission. We would have to make sure that the science output of a human mission is at least 200 times better than the science of a robotic mission, and I’m not sure that’s a case one can make. Likewise, while space exploration, and human spaceflight in particular, has produced a great deal of technology that we now use on Earth in engineering, science, medicine, and daily life — those “spin-off technologies” are, almost by definition, ancillary benefits of a development program that had a different objective. This isn’t a bad thing (and NASA investment is far better at spinning off technology than, say, military investment)…but if we as a society have the goal of getting those technologies, we would just fund their development in the first place, rather than hoping that useful spin-offs come out of another program.
It seems to me like inspirational power is the most common reason cited to continue human spaceflight activities. Here, for example, is the current NASA administrator on Twitter:
Whenever someone tells me that the United States needs to inspire more students to study scientific and engineering fields, I want to ask them: What comes after this great inspiration? When a student says that NASA activities make them want to study math and science — are we, as a nation, going to invest in a technical education system to support their ambitions? Because, right now, we do not; those students are left hanging with the means already at their family’s disposal. And then suppose that these inspired students do get a degree in science or engineering: what do they do with it? Supposedly there has been a “STEM shortage” for years, but I do not see it materializing in a shower of job offers for recent graduates. Where are the university science departments desperate to fill vacant professorships? Where is the bipartisan call to expand the civil services of NASA, NOAA, NSF, CDC, and other national scientific agencies? Where are the private research and development organizations with a backlog of open lab positions to fill? Where are the engineering firm recruiters waiting eagerly outside the doors of college engineering buildings? Our lack of national investment in technology, research, and development belies our stated goals. And, in the vacuum, our previously inspired students are off to Google and Facebook to tweak the algorithms for selling users’ private data to advertisers.
My engineer’s brain struggles with the fact that I can come up with other rationales for human spaceflight, but they seem somehow squishier than the arguments above — the ones I don’t find very resonant after a little thought. After all, the arguments I described so far seem quantifiable: number of undergraduate degrees awarded in STEM fields. Number of scientific papers written by human spaceflight researchers. Number of commercialized technologies. Maybe the solution is to look at the problem with something other than an engineer’s brain.
I think the purpose of human spaceflight should be to expand human life out into the Solar System.
I also think that the reason we don’t often hear this statement articulated is that spaceflight proponents (especially NASA staff) don’t believe this argument will resonate with the public, but I believe they are wrong about that.
People get invested with spaceflight when the engineers, scientists, and astronauts involved connect spaceflight with human experience. Look at Neil Armstrong’s contemplative words as he took his first steps on the Moon. Look at Chris Hadfield singing “Space Oddity” aboard his own tin can. Look at the engineers at JPL whooping as a robot touches down on Mars. And look at the way these things catch the public eye, in a way that a purely technical accomplishment does not. Human experience has a value all its own — despite seeing the pictures and reading about the scientific results, I still want to ask the surviving Apollo astronauts, what was it like?! No, really, what was it like, on the Moon? I think it is worth having people living and working in space, for the sake of connecting the awesome experience of our cosmos to our humanity, and for creating an enduring example of what humans can achieve when we pull together and decide to build something.
Ultimately, I want to see permanent human habitation in space and on other planets. Beyond the romantic notions, there are some simple economic drivers that ought to push us in that direction. Any economic model that assumes growth, on a finite planet, is going to run into trouble eventually — and considering some of the anticipated resource shortages connected to the climate crisis, that point may come sooner than we think. (For another thing, with the world’s most powerful militaries blindly chasing “capabilities” in a way that brings us ever closer to nuclear war, I’d feel a lot more comfortable for the future of humanity if some of us were outside their reach.) No place that we’ve yet discovered will be as amenable to human life as the Earth, even in the face of climate crisis or asteroid impact, but that fact does not mean that we won’t eventually need to have humans off the Earth’s surface.
Now, if that’s really the winning justification for human spaceflight — having humans living in space and developing a culture that connects back to people on Earth — then that implies some changes to NASA’s objectives. Instead of having astronauts “learn to live and work in space,” NASA ought to get people actually living and working in space. This brings to light another reason why we may not see human habitation put forward as the reason for human spaceflight: I am asking for a major, concerted effort on NASA’s part; one that emphasizes long-term approaches to human spaceflight and spacecraft at the expense of the Apollo short-term race approach. We should be looking at regular launches to low Earth orbit, major development effort on in-situ resource utilization, designing and building large habitats that are amenable to long-term human life and work, and allowing a great deal of autonomy to the people in space. But, just as it’s nearly impossible for the US government to close unneeded military bases, it’s proven impossible to reorient NASA from the same kinds of work that has been done at each NASA field center for decades, going all the way back to the 1960s.
Which brings us, of course, to the reason why no humans have set foot on the Moon since the Apollo program: politicians like to have NASA, but they don’t like the implications of having NASA do things. Having NASA do things requires allocation (and re-allocation) of resources. They’ve tried to have it both ways, for decades, by splitting the difference. And we’re left trying to justify the space program as it is, with unconvincing arguments, instead of having a rationale behind the total human spaceflight endeavor and building a space program to satisfy that rationale.
Having a resonant driving force behind human spaceflight could help NASA maintain consistent direction in the decades to come. Do I have the winning argument? I really don’t know. But one thing’s for sure: the arguments we’ve been using so far aren’t working very well, if holding human spaceflight to steady progress is the goal.
I recently read a fascinating book – a diary of a man who spent about a year on a space station. In his journal, he expresses his excitement about learning to live and work in space. He’s proud of the opportunity to represent his country, and he enjoys sharing his accomplishments with international visitors to the crew. He learns to appreciate the automated systems on the next-generation spacecraft sent for resupply. He grows – and eats – plants in space. He worries about ennui, and at one point enjoys playing a practical joke on ground control with a monster mask. He particularly enjoys exercising on the treadmill and observing earth’s geology. His dream is to perform a spacewalk, and he achieves that goal.
You might think I’m referring to astronaut Mark Kelly’s hashtag-YearInSpace. But I’m not.
The man is Valentin Lebedev, and the book is “Diary of a Cosmonaut.” The mission is Salyut-7. The year is 1982.
I found the book quite interesting to compare to recent events in spaceflight. For one thing, the similarity between Lebedev’s Soviet mission and Kelly’s #YearInSpace was uncanny. I’m not even kidding about the monster mask – it came up to the Salyut station with French cosmonaut-visitor Jean-Loup Chrétien. Lebedev’s translator wrote the phrase “learn to live and work in space” even then, back in the early 1980s.
What sticks in my head, though, are the ways the Salyut-7 mission differ from a contemporary NASA International Space Station Expedition. In 1982, the Soviet Union was not able to communicate with their stations over the full length of the orbit. As a result, the two-cosmonaut crew had a much greater degree of autonomy than NASA affords a modern mission. Lebedev and his commander made their own decision to extend their spacewalk. They often decide which scientific experiments to do. They determine much of their own exercise regimen, and they arrange the interior of their station to their liking. These are behaviors that NASA must learn – re-learn, really – if they truly want to send humans out to “live and work” beyond Earth orbit. Especially at Mars, where real-time communication back and forth with mission control is not feasible.
This is not to say that everything was better on Salyut than on ISS. At one point, the two cosmonauts smell something burning – fire is an immediate existential danger on a spacecraft. They’re out of communications with the control center, so the cosmonauts grab a fire extinguisher and go hunting for the source on their own. They find the source of the smell – a component overheating – and take care of the problem. Then, they decidenot to tell ground control. Wouldn’t want to worry them! In another instance, the cosmonauts are rearranging supplies and equipment on their station when they find that a refrigeration unit won’t fit behind a panel. So: they get out a saw, and start cutting the metal panel. (Somebody thought they would need a saw?!) I’m all for astronauts learning to build and repair things in space, but this activity leads the cosmonaut to make the logical complaint. Metal shavings float everywhere, and one goes in his eye. (Fortunately, his companion is able to remove it, ending that cringeworthy episode.)
There’s a lot the modern NASA could learn from these programs of the past: they were steeped in ingenuity and piloted by independent souls who really had the Right Stuff. But there’s also a lot we have learned: to plan thoroughly, to account for then-unknown contingencies, and to sustain a human presence in space for continuous years. What amazes me most, though, is how, over thirty years later, the broad architecture of life on a space station and the research program in space is the same. We need a next step. Centrifugal gravity, closed-loop life support, agriculture in space: We know the kinds of technologies we need to do to truly enable life and work in space. If only NASA would do it.
“The Martian:” Yeah, Martian dust storms are nothing. Yeah, Rich Purnell could’ve explained his maneuver to the NASA top brass with about six acronyms and the phrase “gravity assist.” Yeah, real-life-JPL has almost nothing to do with human space exploration. And yeah, that blow-up-the-Hermes thing is a completely harebrained and terrible idea.
I’ll give the movie a pass on all those counts, because it’s a good story, it gets most things right, and it puts technical problem-solving front and center. But here’s what really drives me nuts about “The Martian:”
“The Martian” highlights what NASAmustdo, but is not doing, in order to get people to Mars.
The Hermes
NASA must build interplanetary transfer craft optimized for deep-space travel, like the Hermes, not single-use capsules designed mostly for reentering Earth’s atmosphere like Orion.
NASA must invest significant research and development effort into “in-situ resource utilization,” such as the robotic manufacture of the fuels and propellants the MAV uses for Mars ascent.
NASA must develop closed-loop life support systems, like Mark Watney has in the water reclaimer and the oxygenator.
NASA must learn to grow food on Mars, instead of trying to send every supply with their astronauts in a single mission.
NASA must build vehicles that provide their crew with artificial gravity, by rotating, to counteract the bone loss effects of long-duration spaceflight.
NASA must learn to let its astronauts solve their own problems when they are twenty light-minutes away from Mission Control.
Most of all, NASA must try a lot of ideas, and they must be willing to see some of those ideas fail, in order to accomplish their ultimate goals.
What astronauts on Mars should be doing
Right now, NASA’s plans for getting people to Mars revolve around a series of activities designed to “learn how to live and work in space.” These activities include astronaut Scott Kelly’s hashtag-YearInSpace mission and the Asteroid Redirect Mission.
Commander Kelly’s mission has the goal of learning how the human body responds to a long duration spaceflight. At the end of his mission, Kelly will be tied for the fifth-longest duration spaceflight. We already have much experience with long spaceflights. Our friends in Russia have even more. So we already know pretty much everything that’s going to happen to him. What’s more, we know ways to mitigate those adverse effects. We need, for example, something to simulate gravity. Like a spacecraft with a centrifuge. That’s a solution science fiction – including “The Martian” – has taken for granted for decades, though NASA has no obvious plans to build true long-duration space vehicles for its crews. They will go to Mars floating in the cramped zero-g environs of an Orion capsule.
NASA also isn’t looking seriously at growing food to keep their crews fed in space. At a conference last March, I learned that all the Mars exploration reference missions involve taking all the food the crew needs for their entire travel, exploration, and return mission. That takes a huge amount of payload mass. Mark Watney did a much better job – and saved a lot of weight – by turning a few potatoes into food for a year. He got fresh vegetables, something his colleagues on the Hermes didn’t even have. Rover data shows that plants could grow on Mars, and creating a spacefaring civilization obviously depends on our ability to feed astronauts – so, again, why not look at the obvious solutions?
The big idea that “The Martian” demonstrates is human ingenuity and problem-solving. To NASA, though, that’s a problem. NASA doesn’t want astronauts tearing components apart and putting them back together like Mark Watney does. They want to have astronauts follow a checklist that has been tested, verified, and validated on the ground in several dozen ways. That philosophy is so pervasive in NASA that agency officials talk about how they need the Asteroid Redirect Mission to “test” solar-electric propulsion – a technology that NASA itself has been using in flight missions since 1998. If NASA really wants to go to Mars, it’s going to have to learn to be more like “The Martian:” being willing to take risks, try new ideas, and give its astronauts leeway to make decisions.
That’s what drives me nuts about “The Martian.” It depicts the space program that I’ve been hungering for for thirty years…and I’m afraid I won’t see such a thing for thirty more, at least.
I have been enjoying “The Expanse” series by James Corey. It’s a space opera set a couple hundred years from now, after humans have colonized and populated the moon, Mars, the asteroid belt, and outer planet moons. Spaceships journey between these worlds, complex engineering projects remake asteroids into habitable stations, and space navies boost from place to place to fight space pirates. I think it’s great because it captures what I wish for humanity’s future: that we will go out and colonize other worlds, that we will be able to undertake engineering projects for the greater good, and that we will become robust enough to weather grand challenges – things we see in the world today as global warming, income inequality, nuclear proliferation, and the like. In many ways, the first three books are about the tension between such grand visions and idealism, and politics and profiteering.
Leviathan Wakes cover, from Orbit
The books are soon going to be a TV series, and I am very much looking forward to see its depiction of space and space travel. (With the exception of parts of the first book, wherein Corey tried to write something horror-ish by being as gross as he could think to be. Whatever. Those are not the good parts of the book.) Corey steered clear of many sci-fi tropes that would have a big impact on the appearance of the series – no artificial gravity here! – and he made sure to build aspects of spacecraft engineering and operations into the cultures he depicted. For example, “Belters” nod and shrug with whole-arm gestures, so that they can be seen when wearing a suit. A good chunk of the books take place in zero gravity. Hopefully that will translate to the screen!
I’m going to take a look at some of the spacecraft engineering concepts in “The Expanse.” Let’s start with the most science-fictional, and therefore least plausible:
The Epstein Drive
Corey very quickly establishes that the powerhouse of his whole solar-system-wide civilization is the “Epstein Drive,” which is some kind of fusion engine for boosting spaceships around. It allows craft to thrust continuously from one planet or asteroid to another, accelerating constantly for half the trip and then decelerating constantly for the second half. This trajectory allows relatively quick travel times between worlds. Conveniently for crew health, and for TV production, the engine also provides “thrust gravity” inside the spaceship. Ships are therefore designed with decks in “stacks” above the engine with a ladder or lift giving crew access between decks, like in a skyscraper.
A fusion engine isn’t a crazy idea, especially not for a civilization a couple hundred years in the future. The problem is propellant. No matter how powerful or efficient your engine is, you will always need to be chucking propellant out the back to sustain this kind of thrust profile.
Picture this: you’re sitting in the middle of a frozen pond. The ice is perfectly frictionless, so you can’t walk or crawl or anything to get back to solid ground. What you do have is a bag full of baseballs. If you throw a baseball away from you, then you have given it some amount of momentum (mass times velocity). Your body gets an equal and opposite amount of momentum: you start sliding in the direction opposite your throw, but much more slowly than the baseball (because its mass is small while yours is big). Great! You have a way to get to shore. But you don’t want to wait out this long slide, so you throw another baseball. This speeds you up a little. Another throw speeds you up a little more. You can keep throwing baseballs until you decide that you’re going fast enough that you can wait it out. That’s basically how spacecraft work now: they thrust for a little, and then coast for a long period of time until they get to their next destination. But what if you wanted to keep thrusting the whole time? You will need more baseballs. Lots more baseballs. You are going to have to keep throwing them, constantly, to keep accelerating yourself.
Writing that a spaceship has a fusion drive instead of a chemical rocket is like replacing yourself in this analogy with a major league baseball pitcher. They will put more momentum into each pitch, and so they’ll go faster across the ice. In other words, their thrust is more efficient. But they will still run out of baseballs at some point, and then they must coast without thrust. The spaceship must stop its burn, cease thrust gravity, and wait several more months before getting to their destination. In the end, high thrust – and, with it, appreciable thrust gravity – should only be active for a short time in any space voyage through the Expanse. As we are learning with ion propulsion nowadays, it can often be most efficient to run at a low level of thrust, but sustain that for a very long time. But that doesn’t give our characters a convenient floor to stand on! So Corey put the word “Epstein” in front of “fusion drive.” “Epstein,” in this case, is short for “magic.” It’s a kind of magic that lets Corey have thrust without propellant, so that he can simultaneously achieve short (astronomically speaking) travel times and keep his crew in thrust gravity.
For a more physically realistic depiction of relationship between fuel, propellant, and thrust, consider Neal Stevenson’s spaceship Ymir in Seveneves.
The Way Ships Move
In the Expanse universe, spaceships are flipping around all the time to vector their engines in the correct direction to change their velocity. And we often read references to what the thrusters are doing on ships. This is all good. But the ships don’t really move the way real spacecraft move.
First of all, orbits barely enter the picture. One scene in Leviathan Wakes involves a character plotting out the likely trajectories of a certain ship, but other than that, the characters can go just about anywhere they want to go as long as they have a good ship to call theirs. Absent the Epstein “magic,” that behavior isn’t really plausible.
Second, though, is that Corey imagines his spaceships rotate themselves around in the same way just about all science fiction authors do: with thrusters. That’s not what most modern spacecraft do! They actually use wheels. Spin a wheel clockwise, and Newton’s third law kicks in: there’s an equal and opposite reaction. The spacecraft spins counterclockwise. Devices that function as I just described are, therefore, called reaction wheels. Other wheel-based devices that take advantage of gyroscopic torques can give satellites quite a lot of agility – without using any propellant. I suspect that the reason why these realistic actuators don’t often appear in science fiction is that there are no obvious cues to their operation: no thruster spurts, no blue glows shining out of emitters, nothing. The ship just starts to rotate.
I was happy to read that Corey’s spaceships are all native to space. There are not many cases where a ship lands, and in those cases, it’s always a small one. The heroes’ ship does once, on Ganymede. With surface gravity comparable to Earth’s moon, that’s not such a stretch for a fusion-drive starship.
28 June 15 Edit: Darn it, I just started Cibola Burn and about the fourth thing that happens is that the Rocinante lands on an Earth-size planet and immediately takes off again. Minus points for that!
The Battles
Space combat plays a big role in the plot of the Expanse books. And it’s a generally great depiction of space combat! Lots of the tactics and technologies are grounded in plausible physics. Ships shoot missiles and guns at each other, the effective range of a torpedo is determined by how close your ship needs to be to make sure the enemy ship doesn’t have time to shoot your torpedo down, the crew all gets into space suits at the beginning of the battle, there’s a ton of electronic warfare activity, and the battles wax and wane in intensity as the spaceships maneuver and orbit.
I’ve long thought that the most effective weapons in a space battle would be simple kinetic slugs or flak shells. My reasoning is simple: the speeds of objects in space are fast enough that a relatively small piece of junk can easily blast a hole through sensitive components. This is exactly why present-day spacecraft engineers – like me – worry about micrometeoroid strikes, space debris, and the Kessler syndrome. In the Expanse, the ships all fire torpedoes or guns at each other. And the results of weapon strikes are devastating: it only takes one torpedo or a few well-placed railgun slugs to take out a ship. Ships blast electronic garble at each other to screw up their targeting systems, but in the end the best defense is not getting hit – so we see the pilot do a lot of evasive maneuvering. I think this is all on the right track from a physics standpoint, though a real space battle with “Expanse-style” ships would probably take a lot longer, involve more orbit dynamics, and require a lot more computerized coordination.
There are two rather implausible elements to the battles. First is the Epstein Drive, which makes the combatants’ maneuvering matter a lot more than orbit dynamics. Second is the “juice,” a drug cocktail that keeps people alive and functioning when exposed to high gee forces. As a way to deal with high gees, the “juice” is just about as good a science-fictiony way to do it as any other, including immersing people in fluid as in The Forever War or inventing some kind of mythological inertial dampener. In the end, though, humans are squishy, precious cargo, and fighting full-on battles with them inside your spaceships doesn’t make a whole lot of sense.
Stealthy Spaceships
(There are some minor spoilers in this section!)
A plot point early on in the first book, Leviathan Wakes, revolves around the appearance of a stealth spaceship. This doesn’t involve any cloaking devices like in the Star Trek universe. Rather, a few spaceships avoid detection by (1) being painted black, which hides them in the visible spectrum, (2) having surfaces that absorb or scatter radar, which hides them in radio wavelengths, and (3) radiating heat out the side of the ship facing away from the enemy, which hides them in infrared. Much as it might give some people heartburn, this is all fairly plausible! The first two points are easy to imagine based on what we know about about the present-day Air Force. Though its not as familiar to the general public, the third item is actually something that comes up all the time in spacecraft design: especially if your satellite has sensitive electronics – like an infrared telescope – the design will include coolers, heaters, baffles, insulation, and radiators designed to emit heat in directions pointing both away from the precious detectors and away from the sun. Even the International Space Station has radiators that rotate to keep them pointing away from the sun most of the time. (The reason is that if the radiators face the sun, they’ll start to absorb heat into the station instead of emitting it out!) Such a “thermal management system” could be designed to, with the other stealth elements, give one side of a spacecraft the appearance of a cool, black spot indistinguishable from the rest of empty space.
A stealth spaceship wouldn’t be easy to build, and it wouldn’t be perfectly invisible – just harder to detect than normal to a lone adversary. And, in fact, both those points are relevant to the spaceships in the Expanse. One crewmember is able to spot a stealth ship on his sensors, but he doesn’t know what it is or how to respond to it. And that’s really all it takes for the stealth ship to accomplish its mission, after all! The very difficulty of constructing a stealth spacecraft actually makes the stealthiness more effective. The characters who cannot conceive that somebody could field a stealth spaceship end up more prone to falling prey to it.
Spaceship stealth makes an appearance other times, as well. At least twice in the series, the heroes’ ship hides itself by masquerading as something it’s not.
Spin Gravity
Lots of space stations in the Expanse, including some embedded in asteroids, spin to provide their inhabitants with centrifugal “gravity.” This is an idea that’s been around the aerospace and science fiction communities for decades, and Corey executes it well. In fact, one of the things I enjoy about the books is how the plot moves between the different environments of planetary gravity, low lunar gravity, spin gravity, and (“Epstein”-based though it may be) thrust gravity. The different gravitational environments contribute to different cultures, and they put the characters in interesting and different situations. If the TV series sticks to the books, we’re going to see low-gee gunfights and damage control teams solving problems in microgravity. Regularly.
All the stations with spin gravity are large, which is the right choice. It means they don’t have to spin at a dizzying rate to get a comfortable level of gs for their inhabitants. There is another benefit, in that the weird non-intuitive kinematics of rotations – Coriolis forces – have less of an effect the larger the rotating space station. These effects can be truly weird, and it can be hard even for physicists to bookkeep all the terms correctly to model them. Something that might happen if you were standing in a spinning space station is that if you drop something, you will actually see it follow a curving path to the floor, and it won’t land at your feet. You will also see it fall at a different speed than you would expect based on the gravity you experience. (I’m planning to write something up separately to go into all the details.)
Anyway, suffice it to say that spin gravity is a strange environment and Corey, like most science fiction writers, doesn’t go into all the details. But spin is the right idea for giving gravity to spacefarers, and I can’t wait to see how the visual effects team on the Expanse interprets all the spinning structures.
All in all, I’m thinking that The Expanse will be good for science fiction on TV. It will be a show with a time period a bit closer to us than, say, Star Trek. And the show will have a wide diversity of environments to challenge the characters. I am looking forward to seeing their depictions of spacecraft and how they move around in space!
This week, NASA announced the selection of nine instruments for a proposed mission to Europa. Europa is probably the best place we know about to find alien life, and the discovery of alien life would surely be an achievement rivaling the moon landing in NASA – and human – history. I have an issue with the thinking presented by NASA in its press releases, though. Agency spokespeople say things indicating that the purpose of the Europa mission is to determine whether or not Europa “could be habitable.” The exact phrase on the web site linked to above is that this mission is part of “our search for oases that could support life” (emphasis mine). That’s not what I want from a mission to Europa. Probes to outer planets come decades apart, so I want to get as much done in a single shot as possible. What I want is to determine whether or not there is life on Europa.
The important difference between those two statements – determine whether Europa could support life and determine whether Europa has life – betrays a slight difference in ambition. I want the big-risk, big-reward activities and objectives of a true moonshot. NASA is hedging its statements, and lowering the bar of its mission goals.
I’m coming to believe that the statement about Europa Clipper’s objectives is symptomatic of a general lack of ambition in NASA’s modern thinking. You can see it in other statements the agency makes: Mars Science Lab Curiosity‘s mission was to determine whether Mars, at some point in its past, could once have been an environment that supported life. The oft-repeated purpose of the “proving ground” activities in the human spaceflight program’s “Journey to Mars” campaign is to “learn how to live and work in space.”
I don’t want to do those things. I want to find out if there is life on Europa; similarly I want to find out if there is (or was) life on Mars, and I want people to live and work in space.
Ironic that a space program – of all things – would lack ambition, isn’t it?
You might think that this is just the public relations spin. NASA is trying to manage expectations, so that they know they can achieve the first objectives of any mission and claim success immediately. Then they can parade that success in front of Congress, while the scientists go after their real scientific objectives in the “extended mission.” But I think the underlying philosophy here is penetrating beyond the publicity level into the actual mission design. It’s easy to find statements from scientists, engineers, and NASA spokespeople that Curiosity couldn’t actually find life on Mars unless that life walked in front of its camera and waved hello. To me, those statements beg the question: why not? We sent a nuclear-powered jetpack-landed laser-toting robot all the way to Mars, why wouldn’t we put some instruments on it that can identify basic things like amino acids? Similarly: NASA sends a probe to Jupiter approximately once per decade (and slowing). Since that rate keeps dropping as time passes, why wouldn’t we try to answer the big questions as soon as we can?
The way NASA now formulates its missions, I can just imagine a variation of Kennedy’s famous moon landing speech: “Our nation should dedicate itself to the goal, before this decade is out, of lifting a man five inches above the surface of the Earth. If that is achieved, this mission is a complete success. As a stretch goal, we might have that flight go to the Moon.”
The great thing about opening up the ambitions of our space program is that it would enable engineers to implement known solutions to the problems we face in space. For example: we know that humans have health problems after spending long periods of time in microgravity. Do we need to keep answering the question of whether or not humans have health problems after spending long periods of time in microgravity? Or can we instead think about the details of building spacecraft that spin to provide artificial gravity? Similarly, we know that there are extreme logistical challenges in sending people to Mars. Do we think about long a mission we could run given the amount of food we can send up with our astronauts, or can we think about the details of having them grow food on Mars?
The difference between those questions is the difference between “learning to live and work in space” and “living and working in space.”
It’s also the difference between the space program we have, and the space program we imagine.
The approach, as the agency has been publicizing with fancy graphics like the one below, seems to consist of the following:
NASA’s tentacles travel to Mars
Send astronaut Scott Kelly to the International Space Station for one year, to learn about the effects of zero gravity.
Perform the Asteroid Redirect Mission, moving a near-Earth asteroid into lunar orbit, to prove that solar electric propulsion works in space.
Assemble a Mars transfer spacecraft in distant Earth orbit out of components launched on the Space Launch System.
Pack everything astronauts need for a round trip to Mars on the new spacecraft and send them on their way!
Keep the spacecraft in space for future trips to Mars. Bring the astronauts and supplies back and forth separately.
Not that these aren’t good brainstorming ideas, but they are not how I would get to Mars. I am too confident and impatient for this plan.
For one thing, we can probably skip this one-year mission. In fact, NASA, I can help you out by zipping straight to the conclusions: Being in zero gravity for a year results in bone loss, muscle atrophy, a compromised immune system, radiation exposure, and changes to the shape of the astronauts’ eyes. We know all that already. Similarly, we already know that solar electric propulsion works – quite effectively, robustly, and scalably – in space. Commercial satellites are flying solar electric propulsion right now, with more on the way. Heck, NASA itself has been flying solar electric propulsion, on missions like Dawn, since the turn of the millennium! Nothing needs proving here. We can take the known technology and use it.
Now, assembling a Mars transfer spacecraft, sending it onward, and reusing it for further exploration – that I like. Here is how I would do it.
First, get one of the companies developing solar-electric propulsion satellites to build a number of spacecraft buses. They will probably run a few tens of millions of dollars each, and they can ride up to space on Falcons, Arianes, or Atlases. (That’s bargain basement stuff for NASA!) Then, tie them together. All I really want are the propulsion systems. Each spacecraft has a propulsion system with something around 10 kW power, and NASA wants to get up to around 100 kW to go to Mars. So, by my rocket science calculations, we need…ten satellites. Or maybe, if we strip out all the telecommunications payloads that these satellites usually carry but I don’t care about for this application, maybe we can get the number down to five-ish.
Four of ’em stuck together (with obligatory blue ion engine exhaust)
Somebody would probably have to do some thinking about the best way to support all these stuck-together satellites. Maybe a truss of some kind. But I’m not too worried about that, because NASA has two decades of experience building modular things and sticking them to trusses in space. They can just do what they do best, using their own well-proven techniques.
Now we need a place to put our astronauts. Preferably a place that has some accommodations for solving the problems that Scott Kelly will be confirming. Many of the major physiological issues with space travel have to do with being in zero gravity. Too bad our Mars transit vehicle can’t bring gravity along with it.
Oh, wait! Sciencefictionknows the answer. It’s known the answer for decades! Spin the spacecraft. The astronauts get to live with a force akin to gravity, pulling them outward along the spin axis.
But building a giant ring-ship takes a lot of time, effort, energy, and resources. I have something different in mind. Something simpler:
My Mars transit vehicle, finished!
On the right, that’s supposed to be an inflatable, cylindrical habitat. (Inflatable things would be terrific for space construction, because they only need a small launcher. Since everything on my vehicle is made of small components, we can launch them once a month instead of once every two years, if they needed a super-heavy launcher like SLS.) This inflatable habitat is tied to the central propulsion core by tethers, or maybe trusses of some type. The astronauts would feel “gravity” pulling them toward the right-hand side of this image (and a little bit downward, because of the thrust). On the left is a dumb counterweight: I’ve drawn it to evoke the empty upper stage of a rocket. It could maybe be long-term storage, but its main purpose is simply to be dead weight to make the spinning easier. The whole vehicle would rotate about the thrust axis, rapidly enough to give the crew at least lunar or martian gravity levels. (The illustration isn’t to scale!)
I’d do one last thing before I send this to Mars with a crew. I’d pack the transit vehicle with enough food, water, and air to get the astronauts to Mars, and for their surface stay.
Not enough to get back, though.
Instead, I would bring seeds. When the astronauts land on Mars, the first thing they will do is become high-tech space farmers. They are going to grow all the food for their return trip on Mars’ surface.
Why would I want to do that? Well, for one thing, seeds are smaller and less massive than full-grown food products. They are probably less expensive – in an energy sense – to get to Mars than those food products would be. Then, on Mars, we can get water and carbon dioxide from the atmosphere, to fuel plant growth. So, over the whole mission, I’m actually saving time and money. There’s also a second reason, one I find more compelling. What’s the point of this whole endeavor if we don’t come out of it knowing how to colonize and explore other planets, and keep colonizing and exploring them? Learning to use the resources on other worlds is fundamental to the future of space exploration. We know Mars has water, we know it has oxygen, and we even know that we might be able to growcrops in its soil. We should focus on that idea and advance it. In other words, I think that – both pragmatically and philosophically – it would be shortsighted and silly to attempt Mars exploration using only what supplies we can bring from the Earth.
We need a space program that focuses on developing the technology to use the resources on Mars to support further Mars exploration. We need to do this in a modular, reusable, scalable manner. We need to make sure our astronauts – no, our pioneers – have the tools, the materials, the infrastructure, and the autonomy to solve their own problems. In other words, we need to stop thinking about how to put a few guys in spacesuits on Mars, and stop thinking about how to have astronauts do science on Mars, and instead think about how to colonize Mars. That requires a lot of little things to come together, with more than a few big things in the mix as well. But, for the most part, we have the technology. We’ve had it for my entire lifetime. We need a space program with the right stuff to use it.