Category Archives: science

The Martian: Does Mark Watney Actually Have Enough Water?

I haven’t read very much of The Martian yet. However, I have read enough to recognize that the chemistry is wrong. Chemistry is the study of the statistical behavior of atoms and molecules as they interact. A lot of chemistry is complex and difficult to apply. What I’ve witnessed so far in The Martian doesn’t go into enough detail to worry about complex chemistry. The problems are rather simple calculations of product quantities based upon inputs. Getting the right answer is a matter of molar arithmetic.

The first instance of chemistry being invoked by Mark Watney has to do with the production of fuel from hydrogen transported to Mars that is reacted with the CO2 in Mars’ atmosphere. He claims that one kilogram of hydrogen will produce thirteen kilograms of fuel. I don’t know where this comes from. I can conceive of a completely unstable chemical formula to get a similar result, but it doesn’t make sense chemically. This made me a bit worried that I did not know something. Therefore, I did a Google search to figure out if there was a well known process for making rocket propellant on Mars.

What I found first was a Geoffrey Landis, NASA scientist and author of Mars Crossing, quick brief on making rocket propellant on Mars. He presents the following chemical formulas:

4 H2 + CO2 –> CH4 + 2 H2O

2 CO2 –> 2 CO + O2 – fixed to make both sides equal

CH4 is methane, one of the components of natural gas. I’m not certain it’s precisely what we want to use as fuel, but for now it will do. However, I’m going to alter the first formula and assume that we have a really efficient machine that doesn’t produce waste water, even though Mark Watney might thank us for that waste water. The new equation is as follows:

2 H2 + CO2 –> CH4 + O2 [equation 1]

To calculate how much CH4 is produced for each kilogram of H2, we need to understand the molar concept of chemistry. Essentially, the notion is that to find the proportion of an element or chemical in a reaction, use the atomic weight to make the calculation. Here’s what we need to know to do arithmetic on equation 1:

atomic weight (rounded):
H = 1
C = 12
O = 16

2 H2 + CO2 –> CH4 + O2
2*2 + 12+16*2 –> 12+1*4 + 16*2
4 + 44 –> 16 + 32 (=48)

4 kilograms of hydrogen produces 16 kilograms of methane. The gaseous oxygen is technically a product, but it isn’t exactly the fuel in our fuel production. So, if we choose to produce methane(CH4) and there is no hydrogen waste, we get 4 kilograms of fuel for every kilogram of hydrogen. This clearly isn’t good enough. So, to reduce our hydrogen to carbon ratio, let’s assume that the fuel making machine is going to produce twelve carbon kerosene, a fuel that would be graded as jet fuel A. We will assume that the process has perfect efficiency and no hydrogen is wasted by making water for Mark.

13 H2 + 12 CO2 –> C12H26 + 12 O2

13*1*2 + 12*(12+16*2) –> 12*12+1*26 + 12*16*2
26 + 528 –> 170 + 384 (=554)

26 kilograms of hydrogen produces 170 kilograms of kerosene. That comes out to less than 6.6 kilograms of fuel for each kilogram of hydrogen, nowhere near our magic number of 13. This isn’t working, but there is another possible explanation that Mark Watney doesn’t explain to us.

Though the O2 is technically not fuel akin to what you would put in the gas tank of your car, even if you used liquified natural gas or kerosene as fuel, this is rocketry. Rockets and explosives burn their fuel quickly, so they don’t get their oxygen from the air. They have the oxygen contained in the fuel, known as an oxidizing agent. Methane isn’t exactly rocket fuel or an explosive, but it will be in a Mars vehicle, which will need to carry an oxygen supply to effect combustion. Let’s see what happens if we count the oxygen as fuel. The following is the combustion reaction. Methane and oxygen react to produce heat, carbon dioxide and water. This is an idealized reaction. Carbon monoxide could also be produced, but we will keep it simple and assume the ideal reaction occurs.

CH4 + 2 O2 –> CO2 + 2 H2O

12+1*4 + 2*16*2 –> 12+16*2 + 2*(1*2+16)
16 + 64 –> 44 + 36 (=80)

From this equation, we can see that the 4 hydrogen atoms are part of a fuel mixture with a total weight of 80. This means that 1 kilogram of hydrogen “technically” could have “produced” 20 kilograms of fuel. This leaves room for significant waste to meet the 13 to 1 threshold. It would be interesting to know what real world system the number 13 came from if it actually did.

Hydrogen to fuel weight ratios are only the beginning of farmer Watney’s chemical calculations. He needs water for his garden and to live on. He has liquid oxygen burning a hole in its tank, itching to become water. Let’s figure out how much water a liter of liquid O2 can produce.

O2 + 2 H2 –> 2 H2O
16*2 + 2*1*2 –> 2*(1*2+16) (=36)

Assuming no oxygen is wasted, which we actually don’t expect, 32 kilograms of oxygen produces 36 kilograms of water. One kilogram of oxygen produces 1.125 kilograms of water. We need to have more information to figure out how much volume of water a liter of liquid oxygen produces, namely, the mass of a liter of liquid oxygen and the mass of a liter of water. The water is easy. The kilogram is defined as 1 liter of water. As Mark Watney would say; Yay metric system! Liquid oxygen is a little more difficult. According to Wikipedia and other sites, it’s 1.141 kilograms/liter. So we need a new equation to convert liters of oxygen into liters of water:

1.141kg(O2)/l * 1.125kg(H2O)/1kg(O2) * 1l(H2O)/kg(H2O) = 1.28l(H2O)

So instead of 1 liter of O2 producing 2 liters of H2O, Mark only gets 1.28 liters of water. He’s going to need 56% more O2 to make the water he wants for his garden. Unfortunately, Mark’s quest for water will continue to be further complicated, because none of his formulas were correct. We need to figure out how much liquid CO2 he needs to make 250 liters of water. We need to look up the density of liquid CO2 (1.015kg/l) and calculate the proportion of the mass that is oxygen.

This was one of those cases where Wikipedia did not seem to be a trustworthy source for information. The density of liquid CO2 was only provided in cubic meters and was only 0.770kg/l, so I checked other sources that specialize in compressed gasses like NASA might use. The Air Products site was one I had double-checked Wikipedia against for liquid oxygen, so I thought it was reliable. When I found another gas vendor site, UIG, that agreed with Air Products, I settled on 1.015kg/l. I liked that they state that measurements were made at 1 atmosphere and the boiling temperature of the liquid. The same pressure and temperature conditions were given for liquid oxygen. If all of the measurements are taken in consistent conditions, the results should be more valid, even if they aren’t taken correctly. We’re looking to calculate relative proportions here.

12 + 16*2 (=44)
32/44 = 0.73

1.015kg(CO2)/l * 0.73(O2)/(CO2) * 1.125kg(H2O)/1kg(O2) * 1l(H2O)/kg(H2O) = 0.83l(H2O)

250l(H2O) * 1l(CO2)/0.83l(H2O) = 300l(CO2)

So, instead of needing 125 liters of CO2, Mark is going to need 300 liters to produce 250 liters of water. At half a liter per hour, it will take 25(not 50, thanks Jake) days for him to produce this much. He probably should have talked NASA into a higher performance CO2 harvester for the MAV.

The drama isn’t over for Mark Watney. We still don’t know if he has enough hydrogen in the MDV’s hydrazine tanks to make 250 liters of water. Hydrazine is a liquid at room temperature and pressure with a density of 1.021kg/l. The chemical formula is N2H4. Let’s figure out what proportion of that hydrazine is hydrogen:

atomic weight (rounded):
N = 14


14*2+1*4 (=32)

Hydrogen accounts for 4/32 = 12.5% of the mass of hydrazine.

292l(N2H4) * 1.021kg(N2H4)/l * 0.125(H2)/kg(N2H4) = 37.27kg(H2)


1*2+16 (=18)

Hydrogen accounts for 2/18 = 11.1% of the mass of water.

250l(H2O) * 1kg(H2O)/l * 0.111(H2)/kg(H2O) = 27.75kg(H2)

That wasn’t too close, but Mark doesn’t have anywhere near the amount of hydrazine needed to make 600 liters of water. He’s going to need over 74% of the hydrogen in his hydrazine to make enough water for his crops. Mark plans to burn the hydrazine inside the habitat, and he rightly assesses that he will get N2, H2 and ammonia(NH3). So long as he doesn’t convert over 9.5kg of hydrogen into ammonia, he’ll be fine. Let’s find out how much ammonia that is.


14 + 1*3 (=17)

Ammonia is 3/17 = 17.6% hydrogen.

9.52kg(H2) * 1kg(NH3)/.176kg(H2) = 53.9kg(NH3) = 118pounds(NH3)

I think it’s safe to say that if Mark makes over a hundred pounds of ammonia inside his sealed habitat, it will no longer be habitable, so there will not be a hydrogen supply problem just yet. Unfortunately, he will be burning far more hydrazine than he planned. I hope he doesn’t need too much extra fuel for something else later…

Why I Hate Science Fiction

I don’t have a very healthy relationship with works of fiction. This especially goes for science fiction. This broken relationship is at least as much a function of my personal defects as it is of poor effort on the part of other writers. My internal critic has a rapacious appetite and is an insomniac. It’s always there, weighing and judging. As I gain a more in-depth understanding of a subject or field, it becomes worse. Not only does the critic become engaged when I notice something is wrong, but also when something appears to maybe be wrong. The critic demands satisfaction, and spoiled by the relatively easy answers of the internet, an interruption and short search usually brings enough information to verify or allay suspicion. When it comes to technical subjects, the suspicion is almost always supported and the critic wonders why the writer didn’t do a little research.

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Reading Between the Lines of Science Articles at the New York Times

An article about one of my favorite scientific subjects, pain sensation, has come up at the New York Times again. In this case, it is a study on acupuncture easing the effects of cancer drugs. I have written about sensation blocking pain before.

Because this study is funded by the NIH, I was hoping to find a free article online, but it seems they are giving Wiley exclusivity for a period of time. What I was able to find was a document that led me to the sham acupuncture treatment, the Park Sham Placebo Acupuncture Device.

The sham was found to be equally effective as real acupuncture. This was not a surprise to me, neither was the fact that both the sham and real acupuncture were effective at reducing measured symptoms. Neuron stimulation relieves pain. Unfortunately, the story is being passed on as both treatments being effective for these cancer patients. Unfortunately, we don’t know that to be the case because of the placebo effect. What I would have liked to see was another placebo that doesn’t provide a nerve stimulus. Something that would test physical therapy like acupuncture against medication for example. Then we would have a better idea what was going on.

It’s a Sad State of Affairs When We Look to ‘Her’ to Understand Artificial Intelligence

I just came across a blog post at Popular Science that says the movie ‘Her’ is the smartest movie about AI in years. The writer of ‘Her’ had no idea what he was doing, which is par for the course, and unfortunate.

I say this is unfortunate, because people look to media in all forms to understand the world better. This takes us back to the idea that there are no big, sexy scientific achievements to inspire people to study STEMS. This led ASU president Michael Crow to respond and start Hieroglyph at ASU to get writers (namely Stephenson and Doctorow) and scientists collaborating. Unfortunately, the effort doesn’t seem to be taking off.

The title of this post is a result of my view of science fiction, which differs from Stephenson in that I’m not so concerned about inspiration as much as education, which is a more peripheral concern to Stephenson. The fact is that many people get a lot of their scientific education from science fiction and news articles. This can lead to a lot of misinformation when the blind are leading the blind. Media about interactive AI should be about the foundation of consciousness, which I previously posted about four years ago. Instead, we get dull acceptance of self-aware AI or irrational fear.

We aren’t being served by the idea that the writer needs only know more science than the average reader. We’re losing an important part of people’s scientific education. It is my hope that just as historical fiction is becoming popular, a blending of popular science and science fiction can become popular once more. A significant chunk of what Katherine and I are trying to present in our science fiction is a view into the systems of science and engineering. Hopefully we are doing so in a way that is enjoyable too.

BlogWriMo: The Long Winding Road

In conjunction with Katherine’s efforts this month on NaNoWriMo, I have decided to write some blog entries which provide a look into our novel creation process from my point of view using the work she is working on this month as an example. I will be posting about the fiction and science that have inspired my ideas as well as some of the content from my notes and our conversations on the world and the story.

This project is in many ways very raw since Katherine first bugged me to get something together maybe two weeks ago when I was working on a paper for my cellular and molecular neuroscience course. As a result, I started work in earnest on Thursday the 29th, a few days before NaNoWriMo started. It also is a very old project, derivative of many failed attempts to bring coherent science to a gritty post-apocalyptic world where the mind and body can do things that would seem like magic to us.

In the past, I have been left unsatisfied with my efforts to define such an environment because it is very difficult to justify radical changes that just aren’t possible with any reasonable derivative of human physiology. In a nutshell, mutation through radiation, biological agents, or natural processes aren’t going to suffice. The leap from here to there is just too large. Drastic physiological changes would need to occur at the sub-cellular level, which would completely derail the organismal developmental process, which is very sensitive to small changes in fundamental characteristics such as the structure of a protein or the presence of an engulfed organism such as mitochondria or chloroplasts.

Almost two years ago, I had an idea that was a result of a discussion about spirituality, which convinced me that the only way the things I wanted to have happen could occur was through influence from outside our universe. Therefore, I would introduce supernatural phenomena through the influence of another universe with completely different physics colliding with ours. Beings and phenomena from that universe, the alterverse, could physically influence ours in ways that defied the laws of physics. Further, some individuals in our universe were magnets for beings of the alterverse and could influence their actions, which would give them the potential I wanted. The phenomena from the alterverse could also have a cataclysmic effect upon civilization.

It seemed like I’d created something that might provide me with what I was after. However, the more I worked on the specific dynamics of the alterverse and my local environment, Phoenicia (what remained of Phoenix, Az), the less satisfied I was. I’m prone to get bored with ideas as I work them out, but this idea was getting away from me, becoming less and less what I’d set out to create. We were about three years into the Weordan project, which still needed a lot of attention, so I just dropped the project.

It’s been churning around in my head ever since.

The solution to my problem may have been hanging around in my head since the first post I made to this blog. Interestingly, this site and blog are a product of what was going on with the alterverse project, which was also called the continua project. Therefore, it seems appropriate that this project has come full circle to the idea that evolution for homo sapiens is primarily occurring through changes in social organization rather than biological changes. Here are the first words I wrote on the blank sheet I started with on Thursday.

Homo Sapiens was constrained by developmental parameters that no longer applied with the development of advanced medical technology and the support systems of modern civilization. Through natural mutation outside of previous survival parameters, new developmental sequences might emerge, eventually being radical enough to cause speciation. However, the same medical technology that enables survival during abnormal development cycles also allows manipulation of genetic and epi-genetic factors to produce novel development cycles and radically different phenotypes.

From this, it should be evident that I like to think about systems to get the ball rolling on an idea. In this case, I had already decided that the source of my unusual capabilities would be a result of human engineering, a process that I’ve come to realize is more complex than just genetics. There has to be an allowance for an organismal development cycle to build exotic structures capable of producing novel capabilities.

This is related to my earlier posts on the singularity in that the continual evolution of social systems would necessitate specialization of humanity into highly specialized, genetically enhanced species that might not resemble the original and would become increasingly insulated from other specialized groups by economic and communication protocols designed to enhance the efficient exchange of information, goods and services. Further, at some point, the system would become so interdependent that a small group of disruptions could cause a cascade that could lead to the collapse of the whole system. This might give me the kind of environment I’ve been looking for, though there are a multitude of complications still to be dealt with.

Fumbling Ockham’s Razor

I often find the conclusions made by scientists to be rather amusing.  A researcher in Australia that is doing otherwise solid work has been paraphrased as having stated that exposure to bright light counteracts myopia. While there is certainly evidence that environmental factors have a strong impact on visual development, this conclusion doesn’t seem to consider the mechanics at work in the eye.

The issues at play in myopia are the shape of the eyeball and the ability of the lens to change shape to provide a wide range of focus. How are the activities of the iris blocking light or retinal stimulation supposed to affect these characteristics? Doesn’t it make more sense that the muscle fibers of the lens will optimize themselves to match the activity that they undergo early in life. If a child stays in an enclosed environment all of the time, there is no opportunity to use long range focus. Likewise, when a child pends all of their time outdoors and never reads or uses a computer, there is little opportunity to exercise short range focus. Presuming that there is a reasonably regular distribution of behavior in any given population, this suggests that there would be a higher prevalence of hyperopia (farsightedness) in places where there is a low incidence of myopia.

I haven’t extensively read the man’s work, so I don’t fully know his position, but it is curious that more obvious features about being outdoors were not mentioned in the article. However, it wouldn’t surprise me if he really thinks this. There is a shocking lack of ability to envision systems within the scientific community.