Other than a busy schedule at work over the past several weeks, and ongoing blogger’s cramp, one of the other big reasons why I haven’t been blogging very much lately is that Tiff and I started reading together again. This is an old tradition of ours that we started back when we were poor newlyweds and couldn’t find a cheaper date than borrowing a book for free from the library, snuggling up, and reading to each other. Anyhow, when we finished the Harry Potter series a few months back, I had decided I needed a break from reading together every night, so I could get caught up on my blogging. I still have another one or two installments to write in my Orbital Access Methodologies series. Seeing as how that hasn’t really been happening, we decided to finish up the last two books in a nine-book historical fiction series we had started back in Santa Clara. To my surprise, reading this series has actually got me thinking more about space development, and so I figured I’d share some of my thoughts.
The series, The Work and The Glory, is a historical fiction adaptation of LDS Church history over the 1828-1847 timeframe, revolving around the lives of a fictional family, the Steeds. While the books do tend to get somewhat preachy at times, and while someone familiar with LDS history might find some of the foreshadowing to be a little weak, the series was overall a good read.
The Mormon Exodus
It was the last two books in the series that got me thinking about the challenges of space settlement. These two books, which we finished a few days ago, cover the Mormon exodus to Utah in 1846-47. In 1845, the deteriorating relationship between the Saints in Nauvoo, Illinois and their non-LDS neighbors got bad enough that the Saints agreed to leave the state by the end of the following Spring. Since none of the other states in the Union at the time were willing to accept the Mormon refugees, Brigham Young and other church leaders decided to colonize the Great Basin in the heart of the Rocky Mountains (which at the time were part of Mexican territory). The theory being that the area was pretty much unpopulated, nowhere near as nice as Oregon and California, and therefore they might finally be left alone.
What the story really brought out was how amazingly challenging of an undertaking the exodus was. The goal was to move all 15,000 Saints (many of them destitute) over 1200 miles through unsettled wilderness, and set up civilization in the previously unpopulated mountain valley around the Great Salt Lake. Much like space, the destination was not existing towns or settlements, and relative to other areas being colonized at the time, the area was very forbidding and unfriendly to human habitation.
One of the interesting points I gleaned from the story was the importance of infrastructure in making it possible to move that many people, and Brigham’s use of advanced teams to help prepare the way for the main body of settlers. The original plan in late 1845 and early 1846, was that a set of advanced companies would lead-out, with the goal of reaching the Valley early enough that summer/fall to plant some quick-growing crops. The hope was that they could get there early enough to provide food for the main body of the Saints to survive the winter by the time they would arrive. Also along the way, they’d be blazing the trail: creating fords, digging down steep river banks to allow for easier crossing, building bridges or ferries where necessary. As the nasty weather that Spring in Iowa Territory bogged the Saints down, these advanced parties were instructed to build temporary settlements at several locations including Mount Pisgah, Garden Grove, and eventually Council Bluffs and Winter Quarters (near modern-day Omaha, Nebraska). They fenced in and cleared farm land, planted and cultivated crops, and then moved on, leaving those crops to be harvested by those who were still coming up the trail.
One of the other major lessons I learned was that settlement by large groups is inherently more complicated than settlement by smaller, individual groups. Especially when you need to move not only the rich and well-equipped, but also the penniless, starving, and destitute. In the end, by the end of 1847, only about 10-15% of the Saints had arrived in Utah. Things ended up taking well over twice as long in the end, but created an infrastructure that allowed everyone, no matter how poor to make the trip. Of the ~60,000 people who made the trip before the railroads reached Utah, many of those literally pulled pulled their way to Utah using handcarts. Without the ferries, resupply settlements, trails, rescue parties, the Perpetual Emigration Fund, and other pieces of infrastructure set in place during the initial exodus, many of those who followed would have never made it. Also, the experience gained in setting up the infrastructure for the exodus provided experience that eventually led to over 500 settlements throughout the Rocky Mountains (spanning from Mexico to Canada), playing a pivotal role in the settlement of the Western United States.
Anyhow, there are far more interesting stories (the Mormon Battalion, the Brooklyn Saints, the Donner-Reed Party, etc) that were covered in those two books than I can do justice too. So, if you can stomach the thinly-disguised religious apologetics long enough, I’d highly recommending digging into some of these books.
Important Differences (ie history never really repeats itself even if it rhymes)
While there are many possible similarities between the Mormon settlement of Utah, and the challenge of space settlement in our century, there are also lots of important differences. One of the keys to successfully learning from analogies is recognizing where they break, and understanding how those differences impact your situation. Because, as one of my history professors at BYU pointed out “all analogies fail at some point.” Failing to recognize the differences between your analogy and real life leads to the sort of silly debates all too common in the space community.
Some of these differences make space settlement more challenging, while others might make it somewhat easier than the colonization of Utah that we’ve been discussing.
- At the time of the exodus, the basic technology for traveling directly to the Great Basin existed. Conestoga wagons, draft animals, firearms, ferries, sailing ships, bridges, etc were all technology that was already in use for commercial and military logistics purposes, as well as playing a big role in the settlement in the MidWest and other places. Much of the technology had been around for centuries or millennia. Not only were the technologies well-understood, but they were commercial available, cost-effective, and off-the-shelf. While there were still improvements being made continuously, as far as settlement was concerned, the commercial state-of-practice for ground transportation at the time was far beyond what the commercial state-of-practice is for space transportation today. A particular case in point is the wagons.
- Along the trail and at their destination, the Mormon colonists were frequently surrounded by ready sources of food, â€œfuelâ€, water, and raw materials for repairs. While it was still possible to starve and die or to run out of water, or to break down in an area where there wasn’t readily available wood (just ask the Donners and Reeds), the general availability of easily extracted in-situ resources was much better for the pioneers than it will be for future space settlers. After all, even the air isn’t free in space. Sure, there are potentially interesting ISRU technologies out there, but they’re nowhere near as mature as cutting wood, shooting buffaloes, carrying water in barrels or canteens, or simply allowing the cattle to graze along the way. Not to mention the fact that you didn’t have to carry all the food for your animals for the whole first half of the Mormon trail…
- While they weren’t as common as would’ve been nice, there were several human settlements in existence along the way by that point. Places like Fort Laramie, Fort Bridger, and Independence, Missouri. While goods were expensive, they did allow for restocking at some price of hard-to-replace items.
- Transportation physics were completely different. While I don’t think that the rocket equation makes inexpensive space travel impossible, it really complicates things, and sure doesn’t make it easy. Combine that with the lack of stopping places between here and LEO, and the transportation physics are much less favorable for space settlement.
- On the side of things that are easier with space settlement, the Moon is a much shorter trip than the trip from Nauvoo to Salt Lake City. The fact that you’re talking about less than a week worth of travel instead of several months makes a huge difference in some of the required provisions and supplies.
- Modern water and air recycling technologies, when combined with freeze-drying can allow for a much smaller amount of food mass per person per given amount of time–potentially over an order of magnitude less.
The Big picture
Basically when you look at where we are today relative to space settlement, weâ€™re nowhere even close to settling the solar system (not even the moon) as the Saints were to colonizing Utah when they were camped at Sugar Creek, across the river from Nauvoo in the bitter winter of 1846. Our civilization as a whole has never even flown 100 people to orbit in a year, let alone 1000, 3000, or 5000.
Just to give a sense of the scale we’re talking about, here are some rough numbers to think about. Suppose it takes at least 6000-7500lb per person (which is probably a very optimistic bare minimum) to settle and survive off-planet. If those numbers are accurate, then in order to settle 15,000 people in space, even just in LEO, youâ€™re talking somewhere around 45,000 tons of material needing to be lifted. Doing that over a 3-5 year period like the first wave of the Mormon Exodus would require 9-15 thousand tons to be lifted to orbit every year. Thatâ€™s over 100 Ares-V equivalents per year, and several orders of magnitude higher than what has ever been done before. And thatâ€™s assuming that they all stop in LEO! Going to the moon would require something like 6-10 times that mass in LEO in order to do that, and Mars or Venus would likely require even more. That gets you to 90-150 thousand tons per year!
At least right now, if some group of 15,000 people were given a similar ultimatum to what the Saints got in 1845, they’d probably be screwed.
ISRU, Infrastructure, and Access
Now, in this article, I’m not going to go into the rationales that could potentially justify settlement on that scale, or even if it is desirable at this point in time, or how soon it would be desirable. I’m just trying to paint a picture of the kind of things that would need to happen in order to make such an exodus feasible in the first place. Think of this section as a sort of roadmap for stuff that would need to happen between now and when space settlement becomes an even remotely realistic possibility.
With that in minde, once you start to realize how mind-bogglingly large the numbers are when you start talking about serious space settlement, you realize that if such a state even is reachable, it will require attacking the problem from multiple directions. There are three different primary areas of development necessary for enabling space settlement: space access, in-situ resource utilization, and in-space transportation technologies and infrastructure.
Even though lower cost, reliable, and very frequent space access is probably the most important step in the near-term (and also the one that has the clearest near-term potential for ROI and thus commercial feasibility), I want to start by talking about ISRU. ISRU helps enable space settlement by reducing the amount of mass you need to ship to orbit in order for someone to settle somewhere in space. Using the historical analogy I started in this post, colonizing Utah would’ve been far more difficult if all the food, draft animal feed, and construction materials for Salt Lake City had to be hauled from Illinois. In fact, if that were the situation, colonization would’ve been impossible. ISRU basically allows you to hack the space access (ie earth-to-orbit) transportation problem back down to a size that might be workable.
ISRU covers a wide variety of areas including in-situ propellant production, production of life support gasses and liquids, production of construction materials, farming, and eventually extracting and processing industrial raw materials, and manufacturing finished goods. Many people in many venues have talked about this subject (particularly Peter Kokh in his “Moon Miners Manifesto” newsletter), but I want to put my own spin on it. For enabling settlement, there are some ISRU areas that are higher leverage than others (ie where you get more of a payoff for a smaller initial investment). As I see it, the two highest leverage areas for enabling space settlement are in-situ propellant production and in-situ construction and construction materials extraction/processing. Of the mass you need to take to LEO in order to settle on the Moon, Mars, the upper Venutian atmosphere, or even the asteroids, most of it is going to be propellant for the trip. Eventually, as more advanced in-space transportation technologies get fielded, this may change, but if space settlement occurs in the near to medium future, I think the importance of oxygen and hydrogen (and possibly some light hydrocarbons like methane or propane) is major. The next biggest mass is going to be the actual structures that people live in and the other buildings, roads, etc. In fact, some previous studies have pointed out that if you can use ISRU to provide for spacious extra-terrestrial facilities, it can have spillover effects on lots of other things. If your internal space is relatively spacious, for instance, you might be able to have more of the work you need to do be done inside, in a shirtsleeve environment, thus allowing you to more directly leverage existing terrestrial tools and processes, without having to do as much redesign.
When you look at in-situ propellant production, something you realize very quickly is that the less you have to ship propellants around, the better. In other words, the closer you can harvest propellants to the place they will be used, the better. That’s one of the reasons why even though it’s a long-shot, I’m so interested in the whole concept of atmospheric propellant gathering. LEO may be halfway to anywhere, but it’s also halfway from anywhere too. If you can gather LOX in-situ in LEO, and especially if you can do it in large quantities at reasonable cost, that would have a major impact on the cost of beyond-LEO transportation. On the other hand, another thing you realize when you study the problem is that due to the rocket equation, propellant resupply on the final legs of the trip have a disproportionately large impact on the overall propellant requirements. Being able to ship a Lunar, Martian, or Venutian lander “dry” saves a lot more weight to LEO than just that landing propellant. It also save the propellant needed to ship that propellant to the destination in the first place. So, at least to me, the two highest payoff places for propellant ISRU are in LEO (if possible) and in orbit around the final destination (for planetary destinations).
Other forms of ISRU such as farming, large-scale manufacturing, extraction and processing of industrial metals, etc. all have an impact on the situation, but for the most part they are much lower leverage–as far as space settlement itself is concerned. We might still see some of the metals extraction and processing sooner rather than later if for instance, it turns out that Dennis Wingo’s theories about lunar PGMs turns out to be true. But as far as actually getting there and setting up shop, propellant extraction, and extraction of the simplest construction materials is more valuable.
In order to use those ISRU derived propellants, you need more matured in-space transportation technologies and infrastructure. You need propellant depots, you need reusable in-space transportation (as well as reusable landers). You need technologies that make reuse easier such as better aerobraking (which may involve both infrastructure like satellites, and space technology like better reusable TPS, ballutes, etc). You eventually need infrastructure to service and maintain those transportation systems. You’ll probably want lots of prox-ops tugs, and you’ll eventually want rescue services (possibly provided by some of the prox-ops tugs). Some of this infrastructure wants to be in LEO (in whatever inclinations have enough demand and/or cheap supply to make sense–and probably eventually multiple smaller depots in the same inclination), and some of it in the vicinity of the destination (for the moon this could mean elements in L1, L2, and/or low lunar orbit, for Mars this probably implies stuff in Mars orbit, or possibly on Phobos or Deimos themselves, for Venus you’d be talking about a Venutian orbit). This infrastructure will probably grow “organically” as market and governmental demand for those services grow. It’s hard to know in advance what exact mix of propellants, inclinations, number and size of depots, etc will make the most sense–so it will need to be market driven (and yes, government customers are a market too–just a potentially very dysfunctional one that needs to be treated with a lot of care).
The core reality though is that in order to be able to even get to the point where large infrastructure or ISRU development can really take off, the space access (ie earth-to-orbit) transportation situation needs to improve. Even if you’re getting all of your TLI and landing propellants from lunar and upper atmospheric sources, you still need to be able to ship vast amounts of material up from earth, and in order for settlement to be feasible it has to be both significantly cheaper than current launch methods allow, but also the sheer quantity of material that needs to be shipped (even with the rosiest of ISRU scenarios) requires a fundamentally different approach to space transportation. While you may be able to do some of the early infrastructure development with existing launch vehicles (tugs and early “pilot-plant” scale propellant depots come to mind), largescale infrastructure and most ISRU other than atmospheric propellant gathering really need lower cost and more frequent transportation.
As Henry Spencer has put on multiple occasions, developing and debugging ISRU on the moon is going to be an involved process, even if it may be a very worthwhile one. The idea that we’re going to design a working ISRU plant, ship it out to the moon, set it up with a few robots, and then start pumping out LOX right away is ludicrous. We know some things about the moon, and there are some good ideas on how to solve some of the more pressing problems, but the reality is that the lunar environment cannot be simulated 100% here on earth, and there are going to be plenty of snags, complications, and unexpected events. Developing hardware, materials, design processes, chemical processes, etc that can cope with the local environment is going to require trial and error and probably several people “on the ground”. It’s going to take time and lots of work to develop spacesuit materials that can handle the dust, making seals and airlocks that do what we want them to do isn’t likely going to be one of those things we get right the first time. And especially once you get into things like metals extraction and processing, developing construction techniques, etc. you see more of the same challenges. And the reality is that the same thing probably applies for Mars, or Venus, or the Asteroids, or even to living in orbit or in deep space. In theory there’s no difference between theory and practice, but in practice there always is.
Improvements in space access need to not only include cost, but frequency, reliability and sheer volume. When you look at the air transportation industry, you’re probably talking about over 10,000 jets flying every day (some of them multiple times per day) from hundreds or maybe even thousands of airfields. With rocketry today we have something like two dozen flights per year from about one dozen or less active sites. If we’re going to get to the point where we’re shipping hundreds or thousands of people and their goods to orbit there are things that fundamentally need to change. One of the biggest changes isn’t just going to reusability, but going to reusable vehicles that can fly from many locations. While what SpaceX is trying to do is technical reusable (or at least recoverable), they’re never going to be able to operate out of more than three or four launch sites (Kwaj, Vandenburg, Canaveral, and maybe Wallops). Same applies for some of the reusability ideas I’ve seen bandied about by other ELV groups. Sure, for larger goods, those types of reusability are an incremental step in the right direction. But in order to get from where we are now to a transportation system that can fly 1000s of people and their goods to orbit every year, ELVs or recoverable ELVs really stop making sense at some point.
In order to get to the point where we could fly that many people and their stuff to orbit every year, not only do you need “reusable” launch vehicles, but they also need to be capable of high flight rates, capable of operating out of many launch sites (including combination airport/spaceports like Mojave), and safe and reliable enough that they can launch at least some of the time over land. In Part I of my Orbital Access Methodologies series, I discussed one such potential approach, in the next part(s) I’ll be discussing a few more.
Getting to a point as a civilization that we’re truly ready to start spreading out throughout the solar system is going to be a difficult process. We’re nowhere even close to where we need to be, and most of the options being investigated by national governments are pretty much orthogonal to where we need to go if we want to see our civilization become a truly spacefaring one. Getting to there from here will require work on radically improving earth-to-orbit space access, developing in-space transportation technologies and infrastructure, and learning how to tap the resources of the upper atmosphere, the Moon, and other planetary and asteroidal bodies. There is useful work that can be done now on all three of these areas, but we’ve got a long way to go, and the engineering challenges are very interconnected. Probably the biggest challenge of all is going to be finding a way to craft solid and profitable business cases along the way to fielding these technologies.
Westward Ho? We’ll see, but we probably have an even rockier road between us and our destination than the Mormon pioneers did in the spring of 1846.
Latest posts by Jonathan Goff (see all)
- Fill ‘er Up: New AIAA Aerospace America Article on Propellant Depots - September 2, 2022
- Independent Perspectives on Cislunar Depotization - August 26, 2022
- Starbright Response to ISAM National Strategy RFC - July 2, 2022