Becoming a Space-Faring Species

The premise of this discussion is not whether humans will be regular inhabitants of space, but what that transformation looks like along with all of the accompanying questions of how, when, challenges, etc. The reason I don’t question the possibility is not for the cynical viewpoint that if we don’t we’ll all die on this world that we’re poisoning, but the positive viewpoint that the most human of virtues is curiosity, and we just won’t be able to help ourselves from exploring.

We’ve seen this curiosity bogged down by industry, economics, politics, and other artificial constructs, but nature finds a way, and it is in humanity’s nature to explore. Whether this is a well-funded, concerted plan put together by governments, or whether several generations of risk takers go into the unknown with minimal support and a high degree of uncertainty is up for debate. If we think back to the colonization of America, the latter was clearly the alternative chosen, so the thought of some wackos deciding they’ve had enough of the Earth and strapping themselves to a rocket landing in Mars is not as unlikely as some would suppose.

How We Do This

Initial Foray

The two extremes for how we become a space-faring race are either a regulated and coordinated government effort backed by the best scientists and engineers, or a small band of crazy people with a death wish. As in most things, it will likely be somewhere in between. We are already witnessing the start of this process with private rocket companies selling their services to the government. As an extension, our most likely path involves riding private rockets heavily regulated and subsidized by government entities carrying career astronauts. Those astronauts will likely have very specific requirements but will be funded by private companies with a vested interest exploiting space for a specific purpose and the means to afford the training.

This is exciting in a lot of ways. Firstly, we are almost at a point where we have the minimal hardware available to make this happen. If we consider establishing a colony on the moon or an asteroid as our first foothold in space, we already have rockets capable of the journey with sufficient payload capacity, and experience with long durations in a vacuum environment (space station). Secondly, we have established public/private partnerships that has the will to make this happen. There are still obstacles politically, but the cooperation between the two most important entities has already been established. We also have a fleet of astronauts large enough for this initial step, as the number of people required will be exceedingly small.

Expansion

After we get our foothold, it will be necessary for a transition to occur focusing on a sustainable privatized system. Assuming some economic benefit for mining, tourism, manufacturing, etc. is proven during the initial foray, risk concerns will be minimized and private companies will be more than willing to invest. The major consideration here is regulation. We too often see this process go awry, whether it’s oil exploration, nuclear power, or the internet. Government funding, research, and initial risk taking opens the door for industry, but doesn’t plan for the “free market” aspect once industry is in control. Regulation cuts two ways: too much regulation stifles innovation, too little leads to unintended consequences, monopolies, and exploitation.

Why Would We Do This

The best answer is “because we can”. It’s a trait of humanity to expand our horizons and explore. There is nothing wrong with this, but it can get out of control. That leads us to the other reason – economics.

Right now it is not economical to go to space. Between the extreme expense of launches, high risk, and regulations there is no business case to be made for the venture. Luckily humans dream enough that we can temporarily suspend logic long enough to overcome these obstacles if we can get over them quickly. And there is sufficient precedent in history that the case can be made for an initial money losing venture. The most evident examples are almost every instance of colonization. The initial costs of the exploration and high risks did not seem worthwhile, but in most cases resulted in a very lucrative long-term situation.

We can’t look at colonization as a precedent without accepting everything humanity did wrong on that front. Mostly exploitation of the natives and dominance by corporations. The former is probably not a consideration, but the second could clearly be an issue we need to defend against, which would be managed by proper application of regulations.

What’s the Timeline

Ten years ago I would have said “who knows?”. But we have a lot more clarity on these points now. The transition of private companies providing space hardware to the government is in full swing, which was likely the largest obstacle. SpaceX has really paved the way here, and despite the ridiculous antics of its founder, it took his vision and perseverance without a clear path towards profitability to break through that boundary. Now we have the most economical launch vehicles in history and the very near potential of large scale personnel transports in the Starship, New Glenn, and other rockets under development.

So technically, it is conceivable to imagine rockets capable of reaching the moon, Mars, or a nearby asteroid and landing with initial colonies sometime in the 2020s. Even though technically a possibility, a very slim probability. This sort of hardware certainly meets our requirements for the initial foray into space, but this technology will still be too slow and costly to make spaceflight a regular occurrence.

In the longer term, we need to overcome some serious technical obstacles and understand long-term survival outside of our atmosphere. The timeline for that transition is very fuzzy. It doesn’t seem like most of the challenges with technology are completely out of reach, but developing and testing the results could be fast-tracked if there is motivation, or stall for decades if mired in regulation. I think it will greatly hinge on our initial success. If we get a small outpost on the moon or Mars within the next couple of decades that works reasonably well with no major incident, likely that will wet our appetite for riskier ventures. On the flip side, some unforeseen catastrophe or engineering error may stop progress in its tracks.

Obstacles to Overcome

None of the hardware is all that challenging compared to past technological advances. At a bare minimum, to survive in space humans need pressure and oxygen, all of which can be handled by some air recyclers and a sufficiently strong balloon (see the Bigelow module on the ISS and you’ll know what I mean). We can spend millions on toilets and recycling systems, but that is just ongoing engineering improvements. The major hurdles are the ones we haven’t found a solution for yet.

Propulsion

Propulsion is the greatest challenge. Everything is far away. While it might be true that with so little friction it would take little energy to get somewhere, the time scale is prohibitive for the (relatively) low power propulsion systems currently in use. That means we need to put a lot of energy into thrust to accelerate to usable speeds. The amount of thrust is limited to protect our human cargo and we have rockets capable of these high thrust values, so our real limitation is maintaining that amount of thrust for extended periods of time.

Consider a rocket that accelerates at .3g halfway to Mars and then deaccelerates at .3g the rest of the way. The trip now is no longer half a year in a small launch window, it’s within a week for a very large launch window. The real problem is carrying the amount of stored energy required for continuous thrust. There are three areas to consider: the mass of the object being moved, the efficiency of converting stored energy to thrust, and the amount of stored energy. For purposes of the thought experiment, consider a Starship (120,000kg) going to Mars (approximately 60 million km) with perfect efficiency using fission with pure U-235. We would still have to carry nearly 300 kg of pure U-235 to make this happen. That doesn’t account for enrichment, reactor mass, reaction mass, etc. That means some real breakthroughs would have to be made in all three areas.

Materials that can withstand a space environment, be serviceable, and be extremely lightweight will be paramount. It will be like going back to the first days of airplanes where weight was everything. We may be able to use current technologies, but the ability to produce our vehicles in space, be able to repair them, and for them to be resilient to the different environments they will encounter will require a new focus on materials.

Rockets are basically unchanged from the days of WWII and are essentially directed continuous explosions. We can’t ignore the laws of physics which requires that to get forward thrust, we must push something the opposite way. Either we push a lot of mass slowly, or we push a little mass very fast. The former is prohibitive because we have to start carrying that mass initially. We will instead so focus on the latter. Our chemical rockets may be reaching their limits in how fast they can propel exhaust gases, so new technologies that can fling smaller amounts of reaction mass extremely fast may be the breakthrough required to make thrust efficient.

Stored energy in classical forms such as chemicals or batteries are certainly not sufficient for regular space travel. At a minimum fission energy similar to current reactors would be necessary, but still require significant updates to increase power density and minimize overall mass of the fuel, shielding, containments structures, etc. Fusion is at least an order of magnitude more energy dense, and the fuel readily abundant throughout the solar system, making it even more attractive. We’re starting to make breakthroughs in fusion which implies it’s just a matter of time, but we will have to progress that to a portable scale – something we are still trying to work out with the much older fission technology.

Environment

Environment is the next greatest challenge. We have shown we can build long-term residences in near space (space station), but as we venture further from the protection of an atmosphere, radiation effects will be especially daunting. Coupled with the long durations of exposure, we’ll have to tackle this challenge on at least two fronts.

Back to materials, we need to develop materials that can provide significant shielding without adding much mass. Our current solution to radiation shielding is mostly putting more atoms in the way, which almost invariably results in dense materials. Looking past the ability for these materials to protect us, they must also be capable of protecting themselves. A “sacrificial” lightweight shield is of little use if it’s lifespan is less than required for space voyages. New approaches to stopping radiation will have to be developed.

The other aspect is far more controversial – genetic modification. Initially we’ll probably be able to make due with drug cocktails that minimize the risk of cancer, but that will not be a sustainable solution. True space-going people will need to adapt to the radiation environment. Other than letting Darwinism take its course (with the accompanying weeding out of the weak and selective breeding over generations) we have to dip our toes into modifying our genome artificially to accelerate the process. Consider the implication – we would be engineering evolution. Setting aside the technical difficulties and risks, the moral and ethical hurdles would be immense.

Our Gravity Well

Our gravity well is the largest single obstacle for our initial foray. Rocket technology has improved to the point were exploding things into space may be profitable in some instances, but heavy lifts required to create our space habitats and vehicles of the future cannot be sustained through this practice. That requires us to continue improving how we escape the gravity well, and how we minimize what has to be raised to orbit.

Chemical rockets are still progressing, but we’re starting to asymptote on their efficiency. It’s also a crude means of moving things. There are many concepts for getting things to orbit without rockets, but none have shown true promise yet. These will have to be developed if we are to democratize space and industry can afford to move people and materials to worksites.

We can minimize the difficulties of our gravity well if we stop moving unnecessary mass. Clearly the human cargo cannot be avoided, but many of the materials can be produced in space given the raw ingredients. Luckily many of the raw materials are available in space, but very spread apart. To access these materials, a concerted effort will be required to capture ore (asteroids) and create processing facilities off of the Earth’s surface. No small feat.

Summary

Can we do this? Of course we can. That is (should be) the mantra of the human species. Will we do this? I believe it’s inevitable, but not for the cynical reasons others have put forward. Will it be hard? Unbelievably. But that has not stopped us before, nor should it daunt us now. I believe that in my lifetime we will start the initial foray into space – with basic colonies on the moon and Mars. Industries may even start turning a profit. We are still likely many generations away from expansion, but as long as we’re moving forward, it’s a step in the right direction.

Your Dose of Aphorisms

This newsletter was less about engineering and more about aspirations for humanity. It’s a big concept – as a matter of fact so big it sounds silly. We have to be able to sound silly once in a while so that the conversation on the possible is had. The quip for today is not my own, but it seems apropos for the topic.

Shoot for the stars and you might hit the moon.