Author Archives: enabity

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…

The Martian: Could a Martian Dust Storm Maroon Mark Watney?

This is an analysis of the technical, scientific and engineering aspects of Mark Watney’s Mars survival story in The Martian by Andy Weir. The primary motivation for criticizing the technical aspects of The Martian is to share the level of scrutiny PHYSIC has been through. I could share early drafts of PHYSIC to demonstrate this, I suppose, but I’m not brave enough to show how thoroughly inadequate my early drafts are. So poor Andy gets another jerk picking on his very popular book instead.

The first technical glitch in The Martian that I’m going to address is at the very beginning of the story. It isn’t an obvious problem. There is quite a bit of room for debate. What really bothers me is the lost opportunity. Weir needs a reason for Mr. Watney to be abandoned on Mars, left for dead by the rest of the crew and without means to communicate. Mars is well known for massive dust storms. Spirit and Opportunity were in danger of shutting down due to insufficient power because their solar panels were substantially blocked by dust from a massive dust storm. Fortunately, dust devils ended up clearing them off and missions continued in full health.

Weir inflicts the mother of all dust storms on our protagonist, winds gusting to about 175KPH/105MPH. That sounds really scary. Winds of that speed would be rated as a category two hurricane. Weathering such conditions in what amounts to a tent in an environment where a hole could end a mission and maybe lead to someone’s death is treacherous. One would think that anything with a large surface area or a flimsy connection would be in danger of being yanked off of the artificial habitat, a comms tower, or the return vessel. Weir reasonably states that the maximum wind speed that the mission is rated for is 150KPH/90MPH, winds that would still be rated as a category one hurricane.

The problem with this entire line of reasoning is that we aren’t on Earth anymore. A windstorm on Mars is nothing like a wind storm on Earth. Atmospheric pressure on Mars is roughly 1% of that on Earth. High speed winds can’t deliver the same quantity of energy on Mars as they do on Earth. To understand how wind is different on Mars, we need to find the appropriate data and equations to give us a sense of scale. First, we need to understand the physics, so we know what is important. The equation for drag works quite nicely.

Force of drag is proportional to fluid density times velocity squared
F ~ p*v*v

I removed the constants and the cross-sectional area from the equation, because we merely want to get a relationship between the force of wind on Earth versus the force of wind on Mars. From this equation, we find out that we need to find out the difference in atmospheric density(p) between Mars and Earth. By referencing the NASA Mars Fact Sheet and Wikipedia, we find out that on Mars p=0.02 and on Earth p=1.2. So, for the same velocity, wind is approximately 60 times as powerful on Earth as on Mars.

If one wants to find out what a 105MPH wind on Mars would feel like, we still have to do some calculating:

Air density on Earth times velocity squared equals air density on Mars times velocity squared
Pe*Ve*Ve = Pm*Vm*Vm
Ve*Ve = Pm/Pe*Vm*Vm = 1/60*105*105 = 183.75(mph)^2
Ve = 13.6mph

Well, that was disappointing. Less than 14MPH. Unless that satellite dish was unsecured, it isn’t going anywhere. If it was sufficiently heavy, it isn’t going anywhere.

It would be disingenuous for me to leave the analysis at this point. The process of a wind storm building up, called saltation, absorbs energy from the atmosphere. Moving the mass of the sand and dust around robs the air of momentum. Therefore, our equation doesn’t accurately represent the force delivered in a 105MPH dust storm on Mars. We really need to understand what is going on with those sand particles before we make a definitive statement that 105MPH Mars wind is not a big deal. The best that I can say with certainty is that there doesn’t seem to be enough energy in the Mars atmosphere to deliver punishing storms and NASA is inclined to agree with me.

This information is an impediment to the story. I’m not certain I’m correct, either. Mostly, I’m bothered by something alien in nature being written off as similar to home. Weir spends no time on the dust storm, as though it isn’t different. How surreal would it be to walk in a massive dust storm with hundred mile per hour winds and not have it completely knock you over? Certainly, a 13MPH gust would not be insignificant when gravity is only 38% of Earth, but explaining these kinds of experiences is the crux of the experience of being a Martian. When these details, the only ones that really matter, aren’t attended to, I feel cheated. What was the point of trying to write a technically accurate account?

What still needs to be addressed is how to maroon Mark Watney under these new conditions. My alternate solution isn’t perfect either. Mark went outside during the storm to attend to the structure holding the communications array to make sure all was secure. As he is working, there is a lightning strike. The dish is destroyed, Mark’s suit and personal communications are damaged and he is dazed. He walks off in the wrong direction in a Martian electrical storm. The rest of the crew looks for him, wrongly concludes he was killed and end up deciding to evacuate.

There are still problems to second guess. I’m not sure how lightning works on Mars. It’s mentioned in the saltation literature as a possible driver of the enormous dust storms. There is also question as to how concerned the crew would be about a lightning strike on the habitat or the Mars ascent vehicle. I still like it better than the notion that there are delicate parts on the MAV. I would definitely think about this more over the long term to come up with a better story.

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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PHYSICa Tech In the News

I’m currently writing the sequel to PHYSIC, which is titled PHYSICa. In this book, I introduce a pair of characters, twins, that change people’s minds by reading and changing their emotions. In the news today, theĀ New York Times has an article about an experiment with emotion and memory in mice in the journal Nature. I miss no longer being a graduate student at ASU and having full access to Nature. However, reading the abstract, I think there is alignment between how these researchers and I see the connections between emotions and memory and the parts of the brain that are involved. Having read what they have to say will probably shift the way I write PHYSICa, but only in subtle ways.

Groundhog Day

Today, tyrannies of the majority are facing off. The collective cultural consciousness is full to overflowing. Punxsutawney Phil saw his shadow, the Superbowl will be played, and gifted actor Philip Seymour Hoffman died at a young age. Is there much room for anything else?

That is the question that runs through my mind a lot lately. As the world becomes smaller through communication, our collective culture shrinks. There are fewer writers per reader, fewer actors per movie/play-goer, fewer singers per listener, fewer artists per viewer. There is more and more overlap. There are fewer professionals per capita. Most artists are hobbyists, which is nothing new. The hobbyists just have more exposure now, so we might individually see more culture while the sum total, particularly of the professional variety, shrinks. The gap between huge successes and those toiling as glorified hobbyists is occupied by fewer and fewer individuals. The middle class is vanishing from art.

This is nothing new. Television and movies replaced stage performances. However, the reduction in stage performances reduced the need for artists, actors and producers, but potentially eliminated repetition that might be viewed as wasteful. This can be viewed as a win for the collective, less talent is wasted on plays and performances that would see a limited audience. Those talents are probably better used in an amateur capacity, at least from the perspective of the collective.

On the other side of the ledger, there is the cultural change in China as rapid urbanization occurs. China’s long-standing, massive agrarian culture is in a lot of ways similar to the Galapagos Islands made famous by Darwin’s studies. China has been a massive network of loosely connected communities that have developed their own local cultures, much like the Pacific island group was for varied species.

As the centralized government in China and the collective popular culture of the West dominate a greater portion of the lives and mind space of individuals, our total cultural capacity goes down in proportion to our population. This can be seen in writing, art and film as more chase after the latest hot topic, sound, look or genre. Everyone wants to be relevant, so they rush to what is popular.

This phenomenon isn’t new. Bigger brains proportionally have more white matter, the long-distance connective neurons. Computer processors also require more layers of wires as they accumulate more transistors. The moral of the story is that a large network needs to spend more resources on highways to facilitate the wide distribution of information. As much as this trend is inevitable, it would be nice to see the bumper crop of hobbyist artists on the internet spend less time chasing after the pack and more time producing something new and interesting.

Morality is an Elephant and We Are the Blind Men

I was re-watching the pilot of Low Winter Sun, and was struck by Lennie James’ commentary on morality as they get ready to kill a fellow police officer. He explains that most people view morality as black and white. Then, some will go to a cocktail party and say it is gray. The character’s observation is that morality is a strobe, jumping all over the place. That made me think on the subject more deeply than I normally would. I don’t know what the writers’ intentions were there exactly, but it was an excellent line for an actor that is superb at playing complex, morally questionable characters.

Further thought led me to a more global view of the subjective morality strobe. The analogy that comes to mind is the story of blind men inspecting an elephant. Each has a different idea of what the elephant is. Since they can’t see from one another’s perspective, they don’t completely understand the elephant or each other. Their disagreement leads to conflict, and none of them know the truth, but presume they do or find themselves confused by a barrage of differing opinions.

Jack the Ripper, Canary in the Coalmine

Jack the Ripper wasn’t the first serial killer, and not the worst. It’s even fair to say that in the grand scheme of things, he wasn’t very interesting at all. Yet, he has a place in history, in the Western Popular Consciousness. The why has been analyzed to death. The newspapers and magazines of the time are blamed for this. However, they were merely the messengers. It seems more likely that the hysteria was incited by technology and this particular case just happened to be in the right place at the right time.

I was inspired to think about this after a conversation with a friend concerning the ending to Model Species. He had a quibble about a small detail which need not be mentioned. What did strike me at the time is that he was looking at the situation with very modern eyes. In some ways, I think this is why we regularly fail to understand the world before the autumn of 1888 when the story began to take off.

It is important to understand the environment at the time. Pictures weren’t common in newspapers back then. The process of converting an image into a plate for print was laborious. However, the technology of photography increased the incentive to automate the process of getting pictures into print. When I looked at the Wikipedia article on photojournalism, I was amused to find the following under the history section:

“The practice of illustrating news stories with photographs was made possible by printing and photography innovations that occurred between 1880 and 1897. While newsworthy events were photographed as early as the 1850s, printing presses could only publish from engravings until the 1880s. Early news photographs required that photos be re-interpreted by an engraver before they could be published.”

Numerous graphic pictures published with the first stories on the murders made the events more real, made it stand out in a way that was new. This reaction made the story a hot seller and spawned the world-wide phenomenon. The 125 years since have made us view news in a different way. It has also changed the way we view and prosecute violent crime. A jury is more likely to convict if they can see pictures of what happened to the victim. They feel compelled to act, whether this is to give just desserts to the powerful or to unfairly condemn those more lowly. The world of 1888 was new to this additional information and was transformed by it.

This has been a quick look at how technology can affect a society, but it reminds me of how monumental a task it is to create a fictional world. It makes me regret the lost opportunity to have made Model Species even better. However, it also makes me want to take a sidetrack from our Apothic Man storyline and explore how a newly devised emetanism changes Gaent and Teria’s next murder investigation and the future of Kenos.

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.