What would be “next level” beyond “Wings of Fire”, my story of an alternate-historical lunar landing where an Apollo-13-style explosion proves deadly, and occurs after the lander is already on the surface? This was, as in our timeline, the early space age, so backups, redundancy, and immense nuclear-powered fleets were not viable yet, so I was thinking it might remain singular, this elseworld version of “the Artemis generation”, who took away the lesson from 1949’s disaster to never allow another Artemis 1: every mission should come with a backup spacecraft for redundancy, in case one fails. At least for the first Mars expedition in 1963 this approach is taken, with two manned rovers of immense size powered by early nuclear reactors, and it proves very successful: the red planet is taken into the realm of human experience, and alien life is discovered, microbes being everywhere, but lichen- or even plant-like forms you can reach out and touch under the most gossamer of ices in the south pole’s geysers. Life as we know it: primitive, yet unmistakably kindred.
By the 1970s, Jupiter is within reach, and the outer solar system tempts the bold as the “Grand Tour” alignment comes into place. And here is where my latest concept comes in: not only an odyssey of flying by the four gas giants, but a manned expedition to Titan, uncovering the secrets of that world, the only one known in our solar system other than Earth to have rains and seas on its surface…but of hydrocarbons, not water.
And it is here that my setting’s go-to approach to space exploration runs into a red light. The realities of life in outer space demand an entirely different toolkit from terra firma: ultra-miniaturized electronics work well enough when you have a specialized large-scale clean room of a manufacturing plant filled with precise machinery and highly skilled personnel to manufacture microscopic circuits for you and ship the resulting product to you in a matter of hours, but electronics don’t like radiation…or dust. And just guess what space is full of? Cosmic radiation and knife-sharp grains of regolith, that’s what.
Already on Mars it might have been a serious problem, but there are solutions: especially in a timeframe when harvesting bulk materials on-site is feasible, and where nuclear power means you’re not as mass-limited as is the case for current space agencies, the simplest approach is to use mass as a radiation shield. Water is especially convenient for this; it’s hydrogen-rich and dense, and so it attenuates radiation well (for this reason water is used today in nuclear power plants). It’s also readily available inside a variety of celestial bodies, and it’s also useful for life support and propellant.
Water is not only drinkable, but splitting it with the on-board nuclear energy yields hydrogen and oxygen, the latter of which forms breathable atmosphere. Of course an all-oxygen atmosphere makes fire much more likely, much more intense, and much more hazardous…but we already know of environments where fire is dangerous on Earth, such as industrial buildings and deep mines, and here is where compressed air shines as a form of energy storage (e.g. the good old “fireless locomotive”). Pressure differences are exploited to do work; mechanically this can still lead to an explosion if something goes horribly wrong, but crucially, fire is impossible, and there are no noxious fumes from combustion, making it far safer in a closed-in atmosphere like what a spacecraft or space colony would possess.
Compressed-air-powered devices, and pneumatics in general, also have the key advantage of being easy to diagnose, repair, and craft from simple, common materials and tools. Conveniently, nuclear energy helps here, by making the compression of air trivially easy. In a world where atmosphere is abundant, energy is abundant, but highly specialized tools and skills are all millions of miles away, pneumatic motors start to look really good. Say goodbye to electricity in outer space…
And not just in tools. We might even see a move away from electricity in computing. Yes, really. Consider that sheathing electronics behind what’s essentially an aquarium’s worth of water will work, but especially for systems that need to be exposed to the elements, a more straightforward approach would be to use fluidic computing. Fluidics employ jets of fluid inside chambers to perform computational operations, instead of using electrons, and such computers are practical to engineer; they’re so practical, in fact, that Phillips actually commercialized them successfully in the 1950s in the form of the MONIAC. Fluidics are intrinsically bulky (jets of water can only be made so small; electrons are far smaller) and they have an intrinsically low “clock rate” since jets of water can only move so fast (electrons move at essentially light speed). So in our world they’re not favored.
They do have advantages that make them interesting for a space habitat, however: their sheer bulk means that they’re much less radiation-sensitive, and dust doesn’t affect them much (dust grains just dissolve in the fluid). A fluidic computer would function just fine even fully exposed to a Martian dust storm and cosmic radiation, long after an electronic equivalent would be rendered an inert brick.
As if that wasn’t enough, the intrinsic scale of fluidic computers, as well as the fact they can be made out of bulk common materials, makes them easy to repair by a layman using general-purpose everyday tools; repairing a fluidic computer is more like plumbing than the (typically hopeless) task of repairing a silicon-based electronic circuit. For an expedition to a dusty radiation-drenched environment far from any outside support, fluidics suddenly look like a godsend.
Even the large scale wouldn’t be a problem; in our offices and homes, space is often limited, but on a spacecraft or a space colony, if your equipment is as big as a house, you can just accrete it on and take it with you. Especially if you have a powerful nuclear energy source to propel you, even the added bulk mass is not much of a problem.
Water works well enough for fluidic computers, but the principle generalizes to any sort of liquid. Indeed, water might not even be the best liquid for fluidics. Consider that biological contamination thrives in water, including that from alien but still water-rich environments like the Martian subsurface.
Consider also that while an entirely pneumatic, fluidic, and hydraulic spacecraft can be envisaged that doesn’t even use electricity, realistically a spacecraft designer would still want to take advantage of the miniaturization electronics can offer. All that liquid shields against dust and attenuates radiation, and is even excellent as a medium for cooling, but water has the inconvenient property of frying electronics, because it’s conductive. Fortunately, a non-conductive alternative is readily available, and is even used today in personal computers that are immersed in liquid: mineral oil.
Mineral oil is aesthetically a lot like water, only it has a more amber or golden cast instead of bluish, and it is composed of higher alkanes, i.e. hydrocarbons, longer-chain than the usual fuels but shorter-chain than the parrafin waxes. As such it is liquid at room temperature, and especially when pressurized it can run at much higher temperatures and pressures than water, which is good for fluidics, and even compatible with known electronics, particularly with specialized high-temperature silicon chips. As a medium that is dense and rich in hydrogen, mineral oil makes an excellent radiation shield, just like water, and like water it can even be used as a source of propellant: hydrogen. Only breathing gas (oxygen) is absent, but oxygen could, in this schema, be kept in a separate tank from the mineral oil, instead of the water tank being dominant.
Mineral oil does have the disadvantage of not being mineable in-situ, but a nuclear-heat-driven chemical plant on board could assemble water into mineral oil, assuming a carbon source is available (carbon dioxide from certain planetary atmospheres and ices would be the standout, though in the outer solar system methane is more abundant).
So will we see pneumatic tools powered by compressed air and fluidic/electronic hybrid computers immersed in mineral oil on our expedition to the outer solar system? Quite possibly. And with the ultimate power source being a nuclear power plant, likely with each vehicle, in the case of our Titan expedition, having an on-board nuclear reactor and a complement of radioisotope thermoelectric generators and heaters.
Where am I going with all this? Well…consider that mineral oil is utterly sterile and hostile to any known life form, impervious to contamination or biochemistry of any kind…but what happens to an architecture like this when it lands on Titan? All of a sudden, the machinery speaks the same chemical language as the planet…and any life forms that might exist on the surface.
Oh, our cosmonauts on this expedition might dismiss the possibility: Titan’s average temperature is 290 degrees below zero on the Fahrenheit scale, with seas of liquid methane and ethane. Mineral oil on the spacecraft operates at temperatures of perhaps 500 degrees Fahrenheit above zero, and is an entirely different chemical. But consider that a life-form that drinks methane instead of water would exist in a soup of hydrocarbons of various chain lengths: unlike water, which has no chemical cousins that are the same basic building block but more polymerized, a life form in Titan’s methane seas would be accustomed to operating with chemically closely related liquids to its native methane. So the exact solvent it uses might be much more flexible than expected: take a microbe from Titan, immerse it in ethane or butane instead of its native methane, and it might not die…
Oh, its biochemistry would no doubt use processes optimized for its cryogenic environment, so placing it in a 500-degree long-chain fluid would surely kill it from the temperature alone…but unlike our life form, even this exotic fluid might not be totally incompatible with its chemistry. Indeed, higher temperatures and a deadly yet not completely chemically alien fluid is exactly the situation where the organisms would experience biochemical runaway reactions that would kill them…and potentially lead to exotic chemical transformations of the surrounding medium as the reaction propagates.
To wit, if the cosmonauts reach out and touch the native life on Titan — more likely than you’d think, since Earth itself has single-celled organisms big enough to hold in your hand; yes, really — and then they do repair work on one of the valves of their fluidic computers without bothering to decontaminate in the most thorough way first…the entire fluid medium their central computer and perhaps even their nuclear power plant is immersed in could become subjected to a biochemical runaway reaction that would gum up everything…turning their fluid reservoir into sludge and their lander into a brick. Beached and shipwrecked on the shores of a cryogenic alien sea, in the dark, with the computers gummed up, and electrical power shut down, with no way to restart…
Worse yet, this is exactly the failure mode that could easily occur on both landers, so the technique of having a backup would prove useless. Both landers could be bricked.
And as if that wasn’t nightmarish enough, consider that it’s thought that Titan has pronounced dry and rainy seasons depending on the time of year, with lakes evaporating and refilling in torrential downpours. A shoreline that looks like an alien beach could easily be submerged in a very short time. And just guess where cosmonauts would likely be exploring and have parked their rovers? The selfsame beach…
So not only would the landers be bricked, they could easily sink in the hydrocarbon sea and be submerged in methane-rich fluid, exactly as shipwrecks do on Earth. Only with more creepy tholin encrustation added on, not to mention that dank omnipresent orange haze. It’s also worth noting there’s no particular reason to think ground on Titan might not be swampy or soft, so under the weight of a presumably rather heavy nuclear-powered rover, the ground will sink over time, entombing the vehicle in ice-rich seabed.
One would think that our cosmonauts would be finished, but the fact their tools are designed to be operated pneumatically and the raw chemical reservoirs and materials are available, both from their beached landers and the outside environment, means they’d actually stand a chance of survival. Helpfully all the tools that would enable them to live, such as tools to mine ice (conveniently water ice is very abundant; it plays the same role on Titan as rock does on Earth, and can be mined for drinking water, breathing gas, and propellant), are operated mechanically or at least by pneumatic motors, none of which would be subjected to contamination. Conveniently, nuclear power sources are available as well, in the form of portable radioisotopes that are red-hot. Plutonium-238 would be in abundance, but polonium-210 would also be favored as a much hotter and denser power source…but one that has a half-life of months rather than decades.
Survival is possible…as is escape. Titan has only a seventh as much gravity as Earth, with an escape velocity to match; even a not-so-efficient rocket can reach space from Titan’s surface. But escape will only be possible while the polonium is still hot enough to drive makeshift propellant, attached to a simple capsule and life support system assembled with their pneumatic-driven tools. Worse yet, while achieving orbit around Titan and then Saturn might be possible, any craft light enough to leave Titan on the power of polonium-heated monopropellant is just not going to have enough power to reach any other inhabited outpost before life support runs out.
But there might be a solution: remember the solo expedition on the Grand Tour? Turns out our lone cosmonaut is well ahead of them, and she has hydrogen to spare. Oh, her original mission was to fly by Neptune, but since she has a nuclear thermal rocket, she only needs working fluid, which Neptune’s atmosphere has in abundance. Her ship is a single-stage-to-orbit type craft designed to enter planetary atmospheres, so she can just dip in and top off, extending her mission to get closer to the deep blue sentinel of the outer solar system than she even dared to dream.
Meanwhile, her hydrogen tank will be sent Saturn’s way, with precise coordination, entirely manual, required for our makeshift capsule to intercept and dock with it, using the thermal heat from their polonium-210 pellets to heat the hydrogen gas and expel it outward, making thrust…enough to leave the Saturn system altogether.
They only have weeks worth of life support, and the nearest manned outpost is at Jupiter, 400 million miles away. Unlike a chemical rocket, however, a thermal rocket can provide steady thrust. 0.001g of acceleration could be realistically achieved with the power density of polonium-210, which doesn’t sound like much, but it adds up over time. The entire distance to Jupiter could be crossed in little over a month, with speeds upon approach at Jupiter exceeding 100 kilometers per second.
The problem, though, is how to slow down. Normally the rocket would be pointed in the other direction, but in the case of our cosmonauts they don’t have enough life support to take the extra time to decelerate. So they’ll have to brake the old-fashioned way: using atmosphere. Only at a speed ten times faster than Apollo or the Space Shuttle, at a planet with hundreds of times as much mass as the Earth…oh, and one that has radiation belts strong enough to kill you within minutes.
Nevertheless, zip by the radiation belts fast enough, angle the hydrogen tank so it can be ablated away, serving as a makeshift heat shield, and Jupiter’s atmosphere will brake them. 100 kilometers per second of speed could be mostly bled off in a matter of a few minutes, but it would entail a sudden sun of blinding-white plasma appearing in front of the craft, the capsule feeling like an oven, as violent g-forces cause the cosmonauts to black out. G-force would be in excess of 20 gees sustained for several minutes, with violent vibrations and shaking throughout. Loss of consciousness would be certain, with severe injury and death being on the table…nevertheless, they would stand an excellent chance of making it out alive.
Once in Jupiter orbit, they could rendezvous with the manned outpost based on the Galilean moons, and recuperate, handing over samples of the contamination from Titan for analysis by their laboratory, and having demonstrated deep-space endurance in the face of adversity without depending on external rescue from Earth, a crucial milestone for space exploration, as is what will prove to be the first encounter with a truly alien biosphere: one that does not use water, or enjoys temperatures that are remotely Earth-like. The precedent for interstellar missions to come would have been set, and they will have come away from Titan having undergone perhaps the greatest human adventure of all time, eclipsing even the first lunar landing.
For me as an author Titan would be a truly fascinating environment to explore, but to date I haven’t thought of a real “hook” that would make such a story compelling, but the intersection of an intertwined system of machine fluid and an unexpected alien life form is science-fictional in the most delightful way.
And yes, I admit I probably have had that idea fertilized in my mind by having seen “Project Hail Mary” in the movie theaters recently, though perhaps it’s the stimulation of a change in scenery to the central coast of California just as well. Or perhaps it’s merely considering compressed-air tools and fluidic computers, and considering what could go horribly wrong if, unlike today’s space explorations, the systems were all hydraulic…which is honestly fascinating in a very hard-sci-fi way yet seems underexplored. I sense a “Wings of Fire” style opportunity here to write a truly special space adventure, and even though I’m not feeling up to putting my storywriter’s hat back on…I’m looking forward to diving into this whole scenario. Titan is a world we should know better, and although I’m sure the Dragonfly mission will someday prove anything I write to be wrong…I’m looking forward to using my imagination here. Watch this space.