Andy Weir — My Geek Hero

Do I just sit back and allow a portrayal of events that, claim to be scientifically factual, to be made to be made into a feature movie, when I know, and can show by basic chemistry and toxicology, that the events portrayed are wrong?

Andy at the JPL
Andy Weir at the Jet Propulsion Laboratory (JPL) in 2015.

If you’ve followed The Dossier you may have read the article: “Artemis” by Andy Weir — Blame it on the Moon. At the time I wrote this I was concerned that “Artemis” the movie might be in the pipeline. Andy has impeccable connections in this regard after having his earlier book The Martian made into a movie, directed by one of the most celebrated directors around in Ridley Scott.

For these reasons, I shouldn’t have been surprised that a feature film adaption has been in the works since even before the book itself was published according to Wikipedia.  Since I wrote my article, I had been struggling with the thought: what is my responsibility? Do I just sit back and allow a portrayal of events that, claim to be scientifically factual, to be made into a feature movie, when I know, and can show by basic chemistry and toxicology, that the events portrayed are wrong? Furthermore, the depicted events could mislead the public if made into a feature-length movie. Being a former science academic (who still considers himself to be in the STEM education business) these things matter to me.

Pondering these matters I sent off an email to Andy Weir. To my complete surprise, I received a response within about 30 minutes: “Ah, bummer. I never checked the total amount …” he wrote. In the short time that it had taken him to reply, Andy had worked through my article and had checked the calculations, he was able to tell me that actually, it is worse than I had calculated because the domes that makeup Artemis are full spheres, half of which are buried under the surface. Using the information from Andy’s email, and allowing for the fact that part of the volume will be made up of the structural thickness of the domes, walls, floors, plant, machinery and filled storage space — say 30% of the total volume. We get the following amount of chloroform in mg/m3 (or ppmv, i.e., ppm by volume) over the whole moon city of Artemis produced from the scenario I described previously (using MathCad software by PTC).
A moon city of 1.5 million m3 is a lot of volume for the chloroform to disperse into, especially when you consider that there is only one cylinder of chlorine and that the mechanism for producing chloroform from methane and chlorine is a 4-step chain reaction (only 1 of 4 steps produces chloroform). In addition, you get HCl vapour at each step. The important point is that for every 8 atoms of chlorine you only get 1 molecule of chloroform (plus 3 molecules of other methyl chlorides and 4 molecules of HCl) [1].   Taking all this into account gives us the following airborne concentration of chloroform produced from a reasonably-sized cylinder of compressed liquid chlorine.
A mere 5 mg/m3, not nearly enough to produce anything like the mass anaesthesia of the lunar population, as described in the book Artemis. Since this is a major plot point, it’s likely to appear in a feature movie based upon the book as well.  I asked Andy about some minor, more realistic, plot changes. he says in his reply: “I don’t do retcon” that is, retroactive continuity. He might have misunderstood my question, I wasn’t asking about the book Artemis, but about the proposed movie. However, I expect that the final responsibility lies with the producers of that movie and not with Andy.

This other problem I have is with the plot device of writers using chloroform as a knock-out gas: it’s’ never a good idea as I pointed out in my original article. Writers always underestimate the amount of chloroform required: you would need an amount of chloroform close to the saturation point of chloroform in the air at 25 °C, about 25,000 mg/m3,  to induce anaesthesia. This is 5000-fold more than the 5 mg/m3 that could be produced in the scenario described in the book Artemis.

Putting aside the shortfall of chloroform for the moment. Imagine if an amount of 25,000 mg/mchloroform were available. In order to induce anaesthesia, this level would need to be maintained for several minutes. Then you would need to ensure that the chloroform is immediately removed or greatly reduced. The timing here is crucial, too long and the good inhabitants of the moon colony would stop breathing, collapse and die. Too little and they won’t undergo anaesthesia — but they might undergo a range of symptoms, such as feeling groggy and disoriented, perhaps enough to fall and injure themselves; or possibly, suffer cardiac arrhythmias, transient hepatic and renal toxicity and acute breathing difficulties [2]. Longer term it is a probable carcinogen. Overall, it’s not something that I would feel good about seeing promoted in a major movie.

An article called “Chloroform Among Thieves” in the medical journal The Lancet of 1865 [3] suggests, with acerbic satirical wit, that the actual mechanism involved — with highwaymen inducing anaesthesia with the barest whiff from a rag soaked in chloroform — might involve “moonbeams extracted from cucumbers.”  In other words, a very impractical kind of science that involves the suspension of belief and wishful or magical thinking, for it to work.

How do you feel about the scenario of mass anaesthesia of the population of the moon being used as a plot device? Do sci-fi writers have a responsibility to educate about science? Do they have a responsibility to promote ethical behaviour, such as not trying to use chloroform as a knock-out gas? Please write your comments below.

Andy Weir read my original article and was so casual and friendly in his email replies. He really does deserve his reputation for being one of the nicest guys around. I felt for him, so I removed some of the sharper comments from my original article. In reply he just said:

No worries about the sharp comments. All’s fair in book reviews. And I invite strong scientific criticism by claiming my books are scientifically accurate. So I bring that on myself. 🙂   Andy Weir.

Andy, you’re my Geek hero! As for getting satisfaction for the scientifically faulty plot points, I need to follow this up with the director.


[1] That doesn’t even take into account that radical chain reactions are known for producing unwanted by-products. Also, the conditions, as described, have oxygen present. Any explosion would simply combust the chloroform produced to carbon dioxide, water and HCl vapour. Though traces of highly-toxic phosgene would result as well.

[2] Chelsea Donovant, “Chloroform toxicity: What is it and why did it kill Mariah Woods?“WECT 6 News,  available online; published 25 January 2018; accessed  23 November 2018.

[3] Medical Annotations, The Lancet, 86, 2200, p 490-3; 1865. Available online accessed: 18th November 2018.

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