I recently connected faith in space colonization to Flat Earth belief, even though these might seem to be on opposite ends of the spectrum—as Flat-Earthers contend that NASA is a hoax and that artificial satellites are not real (wait: because they’re artificial?). What connects these groups is a belief in something that’s not actually real: based more on imagination than fact, and working backwards from what they wish to be true. I’m not saying the groups are equivalent by any stretch, but that they do share something in common, at core.

Anyway, this observation sparked a few conversations that prompted me to resurrect old arguments (see Why Not Space and chapter 4 of my textbook), but also add some new ones. Here, I share some of these new perspectives and related calculations.

Embarrassing Extrapolations

We’ll start by dispatching common sloppy extrapolations. One is framed in evolutionary terms: Life crawled from water onto land, took to the skies, and now to space. No! Each step in evolution offers safety from predation and access to new food resources. Space is the opposite on both counts: unimaginably hostile, and devoid of sustenance. That’s not how evolution works.

Another trope parallels colonization of the continents, casting space as the final frontier. Yet all earthly destinations were endowed with breathable air, drinkable water, and edible food. Moreover, oceanic voyages were likewise in the embrace of sustaining elements. Continents and other planets share very little in common, practically speaking.

Most ubiquitous is a sense of accelerating technology that saw us go from walking to horses to cars to airplanes to rockets. Space colonization becomes “obvious,” which is another way of saying “assumed without any serious contextual thought or analysis.” A game I’ve often played is some variant of imagining a person suddenly transported from 1900 to 1960 and another whisked from 1960 to 2020: which would be more baffled by an unfamiliar world? I have found that two out of three people instinctively imagine the latter time-traveler to be more confused, but that’s so wrong. We’re not actually accelerating: refining, yes. Yet the mythology has such a powerful grip on us that it’s very hard to perceive the waning pace of major new technological capabilities. We imagine the space story will follow a similar pattern of accelerating accomplishment, without any real evaluation of what’s involved.

The ISS is Hosed

The closest we have come to colonization of space is long-term occupation of Earth-skimming satellites like Skylab, Mir, and the International Space Station (ISS)—roughly a thousandth the distance to the moon, or a millionth the average distance to Mars. The ISS boasts continuous occupation for almost 25 years. Its typical complement is 7 astro/cosmo-nauts. One cosmonaut logged 438 days as the longest contiguous stay, while another has racked up the longest cumulative time in space: 1,111 days, or just over three years. Does this mean we’re on track for lifetimes in space? Are the gates open?

“Space station” is in some sense a misnomer, once crucial context is considered. The ISS is re-supplied from the ground every 45 days or so by rocket launches—costing about $150M to $250M apiece. Essentials such as oxygen, water, food, and fuel (for orbit maintenance) constitute the primary payload.

Despite the best technology that money can buy, only 42% to 47% of the oxygen is able to be recycled. We wouldn’t last even minutes without oxygen. Earth’s biosphere provides ample oxygen all the time, but for the ISS, we essentially need an expensive Rube-Goldberg air hose connected to Earth’s surface. Seems like cheating: not really living in space…

Water recycling is better, at 90%. All the same, resupply missions typically deliver about 400 liters of water (20% of total on-board storage) every month or two. Without this crucial contribution, the occupants would be desiccated within a year. So, the station also requires a water hose to the ground.

Simple logic would say that orbits are forever, but simple logic is often wrong (missing context). The ISS is so large—the giant solar panel arrays acting like sails—and so low (1/15th of Earth’s radius off the surface) that residual atmosphere produces enough drag to lower the orbit by 100 meters per day unless boosted back up. The accelerating (runaway) process would result in a fiery re-entry within a year or two—faster if the station has a bad attitude. The ISS therefore runs through about 7,000 kg of propellant each year to stay aloft—more than double the water consumption. Great: now we need a fuel hose as well.

In addition to the required hoses, we also need a conveyor belt of food from the surface. A key tip missing from most (Lonely Planet?) travel guides: there’s no food in space. Not a single cheeseburger has smacked into the side of the ISS in all this time.

I mean, the ISS might as well not be in space, with all these “hoses” hooked up to it. It would be much cheaper (in money and resources) to run this camp on the ground and just pretend the space part, since there’s a huge heap of make-believe in the enterprise already! What real advantage does orbital occupation offer that is not itself predicated on a fantasy future for humans in space? Take away that future, and what’s left to justify the enormous effort?

ISS: Resupply Hog

Resupply launches number about 8 per year—lately using either Soyuz-2 or Falcon-9 launch vehicles. As best as I can tell, each Soyuz launch consumes about 155 tons of propellant, and Falcon-9 about 530 tons (larger payload, but also recovering the first stage adds to fuel burden). At roughly four launches per year apiece, this amounts to about 2,750 tons of fuel, annually (dwarfing the 7 tons required for ISS orbital maintenance).

Comparing this fuel demand to car travel—for which we possess better intuition—we need to account for the fact that rockets must carry their oxygen along, while cars get it for “free” out of the surrounding air. About 30% of a rocket’s fuel mass is in kerosene. That makes a little more than 800 tons per year of hydrocarbon fuel, or about 2.25 tons per day. The equivalent amount of gasoline is 3,000 liters daily, or nearly 800 gallons. Such an amount of fuel would supply enough for a car to go roughly 50,000 km (30,000 mi; more than around the world) every day! Breaking up and allocating to the seven crew members, it’s as if each were driving their personal car 7,000 km (4,000 mi) every day! That’s a helluva carbon footprint, and watch out for speeding tickets—or even slight curves!

The resource demand is a lot more than just fuel, of course. An enormous material (and associated energy) footprint accompanies the enterprise—all of which transpires right here on Earth. My colleague, Mik Dale, computed that every hour a human spends in space incurs an environmental impact equivalent to that of 2,000 hours of an average global citizen. The best way to ensure destruction of Earth’s environment is to try leaving it!

What about waste? “When a Progress spacecraft nears the end of its design life, it is loaded with waste, undocked, and deorbited to safely disintegrate in Earth’s atmosphere.” Thus, ISS is still firmly part of Earth—from cradle to grave. The “space” bit is almost a façade, or subterfuge—akin to a magician’s misdirection.

Exorbitant Cost

Besides the environmental cost—in the form of resources, energy, manufacture/pollution, and waste—putting humans in space (where they really don’t belong, any more than caterpillars do) is outrageously expensive in purely financial terms.

The annual budget for the ISS is at least $2.8B per year ($1.1B for operations and $1.7B for crew and cargo transportation). Spread among seven inhabitants, the total comes to over $1M per occupant per day. What’s the most expensive hotel you’ve ever stayed in? Was it even one-thousandth the ISS cost? It’s as if the mini-fridge charged $50,000 for a bottle of water! At that bargain rate, take several (or else die)!

The price tag for the Apollo project in today’s dollars would come to about $300B. The three-astronaut missions totaled 103 days, amounting to about $1B per day per person! That’s a thousand times more than the ISS! Who would’ve thought anything could make a vacation on the ISS seem cheap?

I can’t point to a real budget for a Mars mission, because it’s in fantasy-land, but the sorts of numbers bumped around are to the tune of $500B. Let’s say it involves 5 crew members for a duration of 2.5 years (travel distance is more than a thousand times that to the moon). We’re talking $100M per day per person—and that’s before the usual delays and cost overruns. Eek!

Getting Radiation Straight

Before I looked into it more thoroughly, I carried the rough rule-of-thumb that the space environment (like the surface of the moon or Mars) had a radiation exposure about 100× that on Earth. Moreover, I figured that the ISS—being deeply embedded within Earth’s protective magnetosphere—would be more Earth-like than Mars-like. My meat-brain was not connecting something it also knew, which is that higher elevations—and especially air travel—present a greater radiation background due to reduced atmospheric shielding.

Expressing in milli-Sieverts (mSv: a measure of biological damage potential), the annual dose on Earth averages around 2 mSv. The cosmic piece of this is only 0.3 mSv. The bulk is from Earth’s intrinsic radioactivity, making its way to our bodies directly from the rock/materials, our food, and the air we breathe (e.g., radon). But the cosmic piece doubles for every 1,500 meters of altitude (initially)—the air itself acting as a shielding blanket (i.e., it’s not just the magnetosphere providing protection: the atmosphere has an equivalent mass of 10 meters of overhead water). At commercial flight altitudes, annual dosage from cosmic rays is about 25 mSv. According to NASA, by the time you’re at the ISS, annual exposure is 160–320 mSv, depending on where we are in the 11-year solar cycle. In empty space beyond Earth’s magnetosphere, one absorbs about 600 mSv per year, while sitting on the moon or Mars is about half that (half of space being shielded by the body itself).

So, indeed the radiation dose on Moon or Mars is over 100× the typical terrestrial dose, and 1,000× the cosmic-ray piece at sea level. But the ISS is not nearly as protected as I imagined: at an average of 240 mSv/yr, it’s much closer to Moon/Mars levels than to Earth levels. I tell ya, that magnetosphere is given way too much credit! In fact, it appears that the magnetosphere offers at most a factor-of-four reduction, so that annual cosmic ray exposure at sea level would only be 1.2 mSv (up from 0.3 mSv/yr) if Earth’s magnetic field were entirely absent. Our atmosphere is the real champion of radiation protection.

Wading past all these comparative numbers, how bad is it, really? On Earth, lifetime risk of cancer is about 40%, and only 2% of those cases are from radiation exposure (the majority being from chemical damage to DNA: carcinogens). I was surprised to learn this, formerly believing background radiation to play a larger role. In any case, one Sievert of exposure is thought to present a 5.5% chance of fatal cancer. Lifetime cancer risk would therefore double (from 40% to 80%) if accumulating about 7 Sv of radiation, which takes about 25 years on a place like the moon or Mars—and half this duration in a tin can away from a giant planetary shield. Long-duration habitation in such places would appear to be a real problem. Unless living in underground caves, a life “above” our atmosphere is almost certainly cut short by cancer. Either way, that’s no way to live.

We already discern increased cancer rates among airline flight crews, where annual exposure is about 70 times smaller than on the moon or Mars (12 times lower radiation, and figuring 30 hours per week spent at altitude). While astronaut exposure per hour is greater, commercial flight crews outnumber astronauts enormously and spend far more cumulative hours being exposed, so that small-number statistics among the astronaut population preclude definitive detection. For example, of roughly 300 ISS occupants, about 120±11 would be expected to get cancer by normal carcinogenic and terrestrial exposure, plus three extra from a six-month stay on ISS (120 mSv): buried in the uncertainty (3 being much smaller than 11). Spend decades in space and you’ll get a “detection” alright, even in a tiny sample size!

Silly Stunts!

I am fond of pointing out that just because we can climb Mt. Everest, and can venture underwater in scuba gear doesn’t mean we expect to live in such places. Note the conspicuous absence of condominiums on either Mt. Everest or the ocean floor. This, despite the fact that one can walk/swim to such places for far less resource use (and money) than space. Safety/rescue is near at hand, and resupply isn’t going to run in the hundred-million-dollar range every month. Water and oxygen are all around, and delicious crabs scuttle past the oceanic enclosure. Living in space is even more absurd than these far-more-benign choices.

Speaking of absurd stunts, how’s this for a comparison: why not live in an airplane that remains in flight indefinitely? Does this sound utterly stupid and pointless and hard? More so than space colonization? Really? What if the unfounded assumption of a human space future turns out to be very far from reality? Whether there’s much point hinges on the imagined future (which could be completely wrong). Meanwhile, it’s actually far easier (less unhinged) to contrive airplane living!

In fact, no great surprise: living in the air has been done! In 1958, two jokers-gone-wild in Las Vegas took off in a Cessna 172 airplane and stayed airborne for about 65 days (into 1959). You heard that right. They refueled 128 times using a hose to a truck driving underneath them on a straight road in the desert. Food and water were also transferred during refuel operations. They rigged a way to change oil and filter in-flight, and basically went until the spark plugs were too fouled to maintain adequate power. Read more here and here.

But if really determined to stay up, one could arrange mid-air transfers to fresh planes. Does this sound like a difficult and risky stunt? Compared to the extreme lengths we go to in arranging space travel, plane-hopping is a piece of cake, and has been done hundreds of times starting in 1920! How hard would it really be to arrange a mid-air airplane docking mechanism, compared to rocket science and space-docking at 7 kilometers per second?

Let’s also compare costs. We’ll start by buying three planes to rotate into service (and maybe to facilitate airborne refueling now that road traffic is worse). Let’s not skimp, either, and pay $500k each for the new planes. A C172 goes through about 8 gallons ($50) of gasoline per hour. That’s $1,200 per day, and we’ll generously add another $800 per day for gourmet food and ground support. And why not throw in $50,000 per year in aircraft maintenance for each plane. We’re splitting everything between two people (the C172 seats four, but we’re being generous in terms of accommodation).

The daily cost works out to $1,200 per person, without the capital cost of the airplanes. Note that the $1M/day price tag calculated above for staying on the ISS also did not include the $150B construction cost, which triples the daily room charge when included. If we do include capital costs for our airplane live-ins, we should amortize over at least 2.5 years for comparison to a Mars trip, but we would be equally justified in making it 10 or 50 years when comparing to colonization (after which payment is due to the grim reaper of cancer). Any of these amortization schedules still keeps the cost below $2k per day per person. Note that whether considering capital outlay or not, living on an airplane is approximately three orders of magnitude cheaper than performing essentially the same stunt on the ISS. Add at least another couple orders-of-magnitude for habitation on Moon or Mars (infrastructure alone would break the bank).

The airplane stunt makes for a useful comparison because it invites us to ask why it seems more silly than humans in space, when space is absurdly more difficult/expensive, and might have just as much purpose, in the end. Perception of the relative value depends entirely on imagined purpose for the future.

Baby Steps, or Silly Stunts?

The space-faithful would likely dismiss my approach as being short-sighted and pull out any number of examples of what someone 200 years ago would have claimed to be impossible based on demonstrations of the day. What we witness now, they would claim, are the first baby steps that are necessary to achieve greater future goals. There’s definitely logic to that, but insufficient context, I would say. We also knew only 10% of physics 200 years ago, and are not still at 10%. We may, in fact, be closer to knowing 100% of the physics that has any bearing on practical living. Any imagined symmetry equating the last 200 years to the next 200 is a brain illusion stripped of most relevant context: a facile trick not carefully examined.

Given the extreme cost and difficulty of living in space, it really is not a foregone conclusion that humans face an extra-terrestrial future. So many considerations flood in at once. Foremost, we are not separate from the ecological web of life that spawned us, and almost certainly are not clever enough to engineer a robust replacement. Not a single human (out of perhaps 100 billion past and present) has detached from complete dependence on Earth. Even astronauts walking on the moon breathed air, drank water, and ate food borrowed from Earth, in an elaborate sort of scuba expedition. Not a single sealed environment (no infusions/deliveries) has sustained human life for longer than 16 months, and even that involved a steady draw-down of initial deposits (at great expense), rendering it an essentially-irrelevant stunt (see next week’s post).

Second, the space era is a reflection of the finite fossil fuel explosion that temporarily transformed the world in the 20th century. The number of humans launched to orbit annually is now down to half what it was 3–4 decades ago. As this era of extravagance becomes unsupportable (via ecological decline, biodiversity loss, climate change, resource limits, aquifer depletion, etc.) something as expensive as space is less likely to persist—especially if no viable benefit is identified beyond the far-future fantasy level and after the megalomaniac billionaires have shot their wads of money into the void.

Third, plummeting childbirth around the globe spells demographic decline, which is fabulous news for humans and the rest of the Community of Life (a much-needed correction that reduces the risk of ecological collapse from our overshoot), but will have economies reeling as growth takes a generations-long holiday: tomorrow will not promise to be “bigger” than today, eliminating investment incentives. The present reality is that over two-thirds of humans on the planet live in countries whose birth rate is below replacement. Asia (including India) and South America are sub-replacement at this point. How would space ambitions survive the economic tsunami that has already formed far out at sea and will arrive in a generation?

Finally, lots of past stunts might have seemed like baby steps to the enthusiasts of the time, but never panned out for a whole host of reasons. Returning to stunts already mentioned, scuba has been around a while, but very little of our collective time is spent underwater. Mt. Everest was first “conquered” over 70 years ago, but only 0.00001% of human egos make the trek, annually. Two guys showed in 1959 that it was possible to stay aloft in an airplane for 65 days, but it wasn’t to become an expanding or even repeated affair. Demonstration does not oblige habitation! Other examples of exciting and well-demonstrated stunts/fads that didn’t survive for practical reasons: supersonic commercial travel; the Space Shuttle (envisioning about a flight per week in a sort of bus-service that ended up being less than a tenth that); jetpacks; self-driving cars.

Casting our space experience today as baby steps is predicated on flimsy faith in some grand space future. Take that unsupported fantasy away, allow the various threads of context in, and baby steps become little more than impressive/expensive stunts at which to gawk. These stunts are still fueled to this day by fantasy (and megalomaniac delusion), in that only misguided belief in future space habitation justifies the great expense in the present. And don’t just take my word for it. Former NASA Administrator Michael Griffin validated in 2003 that the only justification for confronting the herculean challenge of space is ultimate colonization:

For me the single overarching goal of human space flight is the human settlement of the solar system, and eventually beyond. I can think of no lesser purpose sufficient to justify the difficulty of the enterprise, and no greater purpose is possible.

Once the spell is broken this is nothing short of delusional speech. Space stunts might remain impressive for all time, but the likely destiny is that they become silly in the way so many impressive stunts have.

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