Excerpt - How to Science Your Way Off Mars, Ch. 2 (Patreon)

More first-draft stuff for the add-on book for the Maretian hardcopy.

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So- postulate two worlds, one being more or less our own (with a couple of exceptions, like for example a space program capable of sustaining multiple landing missions on Mars beginning roughly around 2028), the other being more marketable than even its creators expected. 

How do people from these worlds end up on Mars?

Since so much of one ship boils down to “because magic”, let’s focus on the other one first- Project Ares, the NASA/ESA joint program that made Mark Watney the seventeenth human being to walk on Mars. 

Andy Weir took his inspiration from various forms of what was originally known as Mars Direct, a continually evolving proposal for how to get humans onto Mars with as little new technology and as many off-the-shelf solutions as possible... except where it isn’t.

There’s a long, convoluted story about engineers, bureaucrats, money, backstabbing, feather-bedding, money, aspiration, money, broken promises, and did I mention money? Well, I might as well not have, because I intend to go into NONE of that here, beyond the short-short version, as follows:

George H. W. Bush had grand ambitions about boosting American education, American science, American prestige, and also American space exploration, and he communicated his desire for a Mars program to NASA and the world in what was called the Space Exploration Initiative. NASA, in response, said, “We’ll get right on it, and a year later they said, “This is all the stuff we want to do. It’ll be beautiful, it’ll be long-term sustainable, it’ll lead to colonization, and it’ll only cost $450 billion dollars.”

Congress took one look at the proposal and said, “Fuck no. We are not building multiple nuclear-powered spaceships. We are not building permanent Mars bases. We are not developing all-new propulsion systems that haven’t even got off the drafting board yet. Fuck you. In fact, fuck you so much that we’re also killing that education program. But we’ll still let you build a particle supercollider in Texas, so don’t whine.” And in 1993, with the project 80% complete, they axed that, too.

In 1992 NASA got a new boss, Dan Goldin, who demanded that NASA scrap its Cadillac-plan ideas in favor of “faster, better, cheaper” robotic space exploration. (It bears noting that most of the “Faster Better Cheaper” missions failed miserably, with Pathfinder/Sojourner being one of the very few bright spots.)

With a new sheriff in Clear Lake, the people who still wanted a Mars mission began thinking: screw repeatable, screw sustainable, screw technological development, what can we throw together on the cheap that will still end in human footprints on Mars? The result of that was the first iteration of Mars Direct.

How does it work? First, send an uncrewed ship, the Mars Return Vehicle, to Mars. It will have a handy-dandy machine on it and about eight tons of liquid hydrogen on board. Once it lands on Mars, the machine will turn that hydrogen, plus carbon dioxide taken from the Martian atmosphere, into methane and oxygen, which it will use as fuel for the return flight to Earth.

Then, once you know the MRV is all set, you launch a second vehicle, this time with human beings inside. This is called the Mars Habitat Vehicle. Once it’s on the way to Mars, it uses its spent rocket booster as a counterweight and spins to provide artificial gravity for the trip. Then, when the ship gets to Mars, it stops spinning, ditches the booster/counterweight, lands right next to the MRV, and then flags are planted, science is done, photos are taken, rocks are put in bags, and then everyone gets into the MRV and goes home?

“But,” you ask, “why do you need two ships? Why not just use one?” And there’s a very good reason for that. The Saturn V, at this point, was out of production, and it was unlikely NASA would get permitted to build new ones or anything like a modernized equivalent. They had to stick to the rockets available at the time, which meant Shuttle derivatives and commercial lifters like Atlas and Delta. And this is a problem when the fuel required just to get off of Mars’s surface and on a trajectory back to Earth runs ninety-six tons. 

That’s eighteen tons more than the Space Shuttle weighed empty. And that’s not just going to low earth orbit, but all the way to Mars. 

Just the fuel, just to get back, weighs more than the Space Shuttle.

Now how are you going to get all the rest of it there?

The handy-dandy fuel machine (which, incidentally, electrolyzes CO2 to split the carbon from the oxygen, then combines the carbon with the stored hydrogen) weighs less than a ton. The power (basically a battery powered by nuclear decay and a thermocouple that turns heat energy into electricity- you know it better as the radioisotope thermal generator, or RTG) weighs less. And the hydrogen sent along runs about eight tons, which is enough to create (combining the mass of the produced methane and the harvested oxygen) as much as 112 tons of bipropellant rocket fuel.

And yes, 112 is more than 96. More hydrogen is sent along than is strictly necessary. That’s not an accident. By the 1990s NASA had become fairly well acquainted in the use of liquid hydrogen as a rocket fuel (direct, not turned into methane or anything else). And they’d had close to thirty years of engineering experience that told them one basic thing:

Hydrogen really, really, REALLY does not like being contained. 

Remember, hydrogen is the smallest, lightest thing that can be called an element. Over 90% of all hydrogen is just one proton and one electron. Even its molecular form, H2, is tiny compared to literally any other tangible substance you care to name. That means, not only will H2 sneak through any gap or loose spot in a seal it can find, it will sneak through gaps you couldn’t imagine even existed. Keeping it cold enough to be liquid- which means 33 degrees above absolute zero, or to give a comparison, about twice as cold as summer on Pluto- well, that helps, but that’s hard to sustain short-term and nearly impossible to sustain long-term, because even under pressure some of that hydrogen will turn back into gas and start looking for ways out.

And if that wasn’t bad enough, hydrogen can even escape through the solid walls of its containment vessels. Not only is hydrogen really, really tiny, it’s also really, really reactive. It wants to get with other elements and make fascinating compounds... and then it wants to move on to bigger and better things, especially if they involve oxygen, fluoride or chloride. 

That means that, no matter what apparently stable, non-reactive material you make the tanks out of, hydrogen atoms will- very very slowly- combine with the material to form new molecules, then break off and combine with other molecules, and so on and so forth, until- again, very gradually- they end up outside the tank or balloon. 

All of this means that it’s not a matter of if the hydrogen escapes. It’s a matter of how much hydrogen escapes. The minds behind Mars Direct understood this and planned accordingly, and thus said, “If we want to make sure we have 96 tons of fuel and oxidizer, we need to send enough hydrogen for 112 tons of fuel and oxidizer.” And that works out to eight tons of hydrogen.

“Okay,” you say, “but maybe we could speed the process up? After all, how long does it take to turn hydrogen into methane?” 

Answer: ten months, if you’re on Mars with a power supply not quite strong enough to run six household LED light bulbs at once.

“Okay, so the tank has to hold the hydrogen for ten months.”

Nope. It has to hold it for SIXTEEN months.

You see, using chemical rocket propulsion, the trajectory that combines the shortest travel time with the least amount of fuel used takes six months to get a ship from Earth’s surface to Mars’s surface.

“Okay... so you send the return ship because that somehow fits on 1990s rocket technology even though it’s already heavier than anything NASA has sent up before this point, and that saves about eighty-five tons. And then sixteen months later the astronauts arrive?”

Nope. From the launch of the MRV to the landing of the MHV would be thirty-one months.

“I’m lost.”

I don’t blame you, but explaining that takes us into interplanetary trajectories, and I want to save that for a later chapter. For now we’ll just leave it at this: the best time to go from Earth to Mars only happens roughly once every twenty-five to twenty-six months. That means, if you’re launching your return ship separately from your going-out-there ship, and it will take sixteen months for the return ship to be ready for you, you have to wait until that twenty-five or so months is up before you follow it.

And just to be perfectly clear, under no circumstances is NASA EVER going to launch humans on a trip to Mars unless they are ABSOLUTELY CERTAIN they can get them back. Under Mars Direct as originally drafted, If something happens to the MRV- it crash-lands, the fuel plant explodes because the hydrogen found a really easy way out of its tank, it just fails to make enough fuel, whatever- then the astronauts do not leave Earth at all. 

And we’ll leave it there until Chapter Seven. Suffice to say: original Mars Direct- two vehicles, launched a bit more than two years apart. The astronauts land and wait eighteen months for their return trip to Mars because of the trajectory thing, and then they hop in the MRV and spend about eight months getting home. 

All told, the astronauts spend thirty-two months in space or on Mars. 

And that is, as they say, a Problem.

Ever since human spacecraft became something astronauts rode in rather than something they wore (and if you want an explanation for that remark, feel free to check out the Mercury capsule trainer at Space Center Huntsville or the actual Mercury in the collection at Space Center Houston), every agency that has sent people up has grappled with the consequences of long-term space flight. 

The logistical requirements, ironically, are the easiest part. About a kilogram of food per person per day, with about 3100 to 3500 calories per day, and some means of generating or recycling water (because, after all, the human body only borrows water- everything that comes in, goes out), and above all enough oxygen (and carbon dioxide removal, which is actually the bigger problem so far as air is concerned), and you’re golden. And we’ll look at those requirements when we begin talking about food and oxygen in later chapters.

But the medical issues are a lot trickier. As scientists only realized after the fact, the entire Apollo program was absurdly lucky that no coronal mass emission- that’s when the sun hurls a big, hot, intensely radioactive chunk of itself out into space to be carried by the solar winds out into the universe- happened during any moon flight. The Apollo-era spacecraft, and especially the lunar module, would not have protected the astronauts from a lethal dose of radiation if a CME swept through Earth’s local space. (Low Earth orbit is protected- mostly- by Earth’s magnetic field, although that same magnetic field funnels radioactivity into two zones called the Van Allen Belts, which are survivable for transits but not a place you want to hang around in.)

Even without CMEs or other space radiation (which we’ll get into in detail in the next chapter), microgravity over a prolonged period does various nasty things to the human body, which evolved over millions of years to function in an environment where everything is being pulled down at a constant 9.8 meters per second every second. Without that pull, fluids shift in the body. The eyes change shape, which leads to sight issues later in life. Muscles don’t have to work so hard, which means they atrophy- especially the heart. Bones leach out their calcium, becoming weaker and brittle. Even basic cellular functions run a bit differently in zero-G, which- again- means an increased risk of cancer. 

But the single biggest problem, and the one scientists are still struggling to find solutions for, is the psychological effect of prolonged space flight on human beings. And in this case, it’s not the lack of gravity that’s the problem; it’s the isolation combined with the almost total lack of privacy.

For centuries, sailors have been known to be eccentric, violent and (once on land again) completely uncontrollable. This extends to their officers, which gained an almost universal reputation: no matter how nice and gentlemanly they might be on land, after even a brief time at sea they became short-tempered martinets prone to feuds, grudges, temper tantrums, and violence. Military, civilian, didn’t matter- the reputation seems to be universal among all cultures which engaged in sea voyages of longer than a few days’ duration.

Today, thanks to much more scientific understanding of human nature, we can guess why. After all, these were dozens or hundreds of men cramped together in excruciatingly tight company, completely devoid of privacy or the ability to get away from one another, and completely isolated from contact with anyone else in the world for long stretches of time. For large portions of that time they had nothing productive to do, no distractions or entertainments except alcohol and gambling (both of which lead to feuds, grudges, temper tantrums, and violence). 

There were, of course, other factors. Sailors often spent weeks with horrible food (aged salt pork, weevily hard crackers as a substitute for bread, very limited amounts of fresh water (which became more foul for every day it spent in the casks on the ship) and, if they were very lucky, a few vegetables and fruits to ward off vitamin deficiencies (mostly peas in the English service before the 1790s, when citrus juices became a requirement). Paydays were few and meager except for officers (as even on merchant ships the owners kept as much of the profits as they dared). And, on military vessels, most of the ordinary seamen were there involuntarily- forced into service and kept in line by violent discipline in which almost half the infractions were punishable by death.

Those other factors, though, don’t apply to space flight. Every space agency (yes, even the Russians) goes to extreme lengths to find ways to make the food as good as possible (which is hard, since in microgravity aromas don’t rise, which means the human sense of smell almost stops functioning, leaving everything tasting bland). Pay, though not wonderful (basically indexed to military officer pay scales) is actually liveable. And nobody- absolutely nobody- goes up on a rocket without volunteering and then going through years of training. 

But the combination of being shut in a small space, crowded too close together with a few other humans, while being totally isolated from the rest of the human species, is still a massive problem.

The Soviet Union first tried addressing this problem in the 1970s. After their moon shot failed, they looked into using their failed moon rocket, the N1, for a flyby- not a landing- of Mars. Under the best circumstances this trip would take more than a year, during which the cosmonauts would be shut up in a Soyuz or similarly sized capsule. Now, assuming the cosmonauts weren’t killed by a massive explosion on the launch pad (if you know about the history of the N1 booster, this was not the way you should bet), could they actually endure a year-long road trip in a space about the same as a Honda Acura?

The answer didn’t take long in coming: No, they absolutely could not. In fact, the first couple of experiments ended very early- less than three months- with one of the crew trying to murder one of the others. This came after weeks of near-daily fist fights between the crew members. And yes, because it was Soviet Russia, booze was involved. 

Despite this setback, experiments continued as the Mars idea was quietly forgotten and replaced with what would become humanity’s first orbital space station project. The test facilities were enlarged, and then enlarged again. After the fall of the Iron Curtain, members of other space programs joined the experiments. And, eventually, the most recent experiment ended in 2011 after a year and a half of isolation, with (for the first time) no major incidents between the crew members. (This, of course, came after decades of experience with space stations, where crew members were expected to spend a minimum of six months on orbit, which obviously affected the ground-based experiments.)

In the course of all this isolation testing, everyone got a pretty good idea of the psychological effects of isolation and how to deal with them. 

The first lesson learned, of course, was that human beings need elbow room and personal space. Even the most compatible of personalities produce friction if kept too close together for too long. (NASA was probably extremely lucky that its long-term duration on orbit test, Gemini VII, had Jim Lovell as one of its two crewmen, as Lovell was an amiable and personable man without being excessively outgoing. The other crewman, Frank Borman, was much less so.)

The second lesson learned was the importance of ensuring that crew members could work together through months or years of on-the-ground training together. (Perhaps the Lovell-Borman pairing owed less to luck than first appears...) Psychological studies and observation were critical for any long-term space mission. (Incidentally, the hard-driving, alpha-male type personality which was the “Right Stuff” for the Mercury Seven has since been found to be entirely the wrong stuff for space flight in general, where teamwork and mutual support are critical.) 

Another lesson that came up during the NASA Skylab experience (and really should have been noticed sooner) was the importance of leaving a bit of unstructured free time to astronauts. Attempts by NASA scientists to cram even more experiments and observations into the Skylab 4 led, towards the end of the mission, to the crew members declaring a one-day strike so they could catch up to their other tasks and rest. NASA never allowed any of the crew to fly again, but they took the lesson (especially as it was far from the first time this had happened), and beginning with the Shuttle era more free time was built into the schedule.

That said, it also became evident quickly that a strictly structured life, with plenty of tasks to do every day, was absolutely necessary for long-term space flight. People in isolation with nothing but free time, after a couple of weeks, cease to be productive; they just sit around and vegetate. Keeping people busy and on schedule slows, but does not stop, this process. So, while it’s important to allow a bit of free time to astronauts, it’s equally important that it be only a bit and not full-time. 

Finally (and obviously), alcohol and other drugs make all of the above psychological effects of isolation much, much worse and bring them on much, much more quickly. Including wine or vodka in the rations, even in small amounts, invariably led to trouble. (This goes a long way to explaining why, in the ground-based experiments, almost all the incidents came from Russian crew members, including violence and sexual assault.)

So, apply this all to Mars Ascent, in which four astronauts were due to spend two years in one capsule barely larger than Apollo before transferring to another, smaller capsule for the ten month flight back home to Earth. 

Yeah. This, obviously, was never going to work.

So NASA changed it, putting back some of the bells and whistles that Mars Direct had been intended to eliminate. The large mother ship, rotating on its axis for artificial gravity, provides more living space for the trip. The MAV remains, but since it no longer needs to go any farther than Mars orbit and doesn’t need to carry months of food, it now requires less fuel and oxidizer- about fifteen tons instead of ninety-two. A new Mars Descent Vehicle (MDV) replaces the Mars Habitat Vehicle, with materials for a prefabricated surface habitat soft-landed on-site so that the astronauts don’t have to live in a capsule. 

All of these things provide massive quality-of-life improvements, to say nothing of whittling down the launch mass of both MAV and MDV to something 1990s-era launch systems could accommodate without absurd, even kerbal levels of engineering. 

But none of them solve the most critical problem with a Mars expedition: time. Three years is still unworkably long. 

Andy Weir’s solution: VASIMR.