Reading has always been my favorite pastime during the summer. This summer with various travel plans impacted by COVID-19 once again, I indulged myself with reading in my spare time. Two books, both written by Andy Weir, The Martian and Project Hail Mary are particularly captivating. Both stories are about using math and science to figure out how to survive in space. The fact that they are unlike any other books that I’ve ever read prompts me to write a book review on each of them; this being the first of the two.
When Weir wrote The Martian, he had been a software engineer for two decades. Due to his passion for space, Weir started writing The Martian alongside his regular engineering job. He started purely for his own interest, and didn’t think he would ever publish it. He had posted the chapters to his blog for ten years before he finally decided to pull everything together, and self published the book on Kindle for 99 cents. While he was writing, he had always been particularly focused on including real science. In order to ensure the math and science behind the story was accurate, he would thoroughly fact check the topics he wrote about. This, in my opinion, is the most impressive quality about The Martian.
The Martian became an instant success after it was published in 2015 due to Weir’s adherence to fact, and was on top of the New York Times best seller category for about 20 weeks. I have read a few science fiction books before, but all of them are too fictional to be realistic. The Martian does a good job of intertwining the fictional and the real. Below are some important math and science knowledge points mentioned in the book which you may find interesting :-)
1- In the book, a “sol'' has been used to refer to a day on Mars. The reason why Weir didn’t use “day” as a measurement for a day is because a day on Mars lasts 24 hours and 37 minutes, which is slightly longer than an earth day. Mark Watney was stranded on Mars for 543 sols, which is equivalent to 557 earth days. One year on Mars is 687 earth days long, which is equivalent to 1.9 earth years. This is because Mars is further away from the sun so it takes longer to orbit the sun. This level of detail adds much appeal to readers, especially science geeks just like Weir himself.
2- In order to survive on Mars for an extended period, Watney had to grow food to supplement his food reserves. However, the reality is that Mars is very cold because it can not trap the sun’s heat due to its thin air and because it is further away from the Sun compared to Earth. The temperature on Mars averages around -80 degrees Fahrenheit. With the dire conditions and atmosphere, no known earth plants can survive on Mars when exposed to Martian surface. Weir then wrote extensively about how Watney built the greenhouse with the proper environment for growing plants like potatoes - why potato but not any other plant was picked by Watney was also very interesting - you should read the book to find out why! I particularly enjoyed this part of the story, i.e. growing potatoes on Mars as it refreshed my fond memories of various science classes that I had at high school including biology, chemistry and physics. The process included:
How to make water: Watney produced water by burning leftover rocket fuel and extracted the hydrogen from the resulting chemical reaction
The greenhouse, as Watney figured out, needs the right level of light, carbon dioxide, water, temperature, and humidity. The amount of each is derived from detailed mathematical equations and formulas, just as how water, and eventually oxygen is made
Mars has very weak gravity (its gravity is 37% less than on earth), weak gravity alone doesn’t deter plant growth as long as there is sufficient light, CO2, water, temperature and humidity that were created by Watney in his greenhouse. The fun fact that I learnt is, plants on Mars could happily grow three times taller than those on Earth
How to make oxygen (for himself): Mars' thin atmosphere is made up of 95.9% carbon dioxide and 2.7% nitrogen. Watney used an electrolysis system to produce oxygen, which split water molecules into their component oxygen and hydrogen atoms using electricity
3- Watney had to plan out a way to survive at least 500 sols, until the earliest rescue could possibly arrive...How did Weir come up with a reasonable number of sol days to make the story realistic? Besides assuming the days it took to build a new rocket and find a right launchpad, Weir based his calculation on known facts including distance, and relative positions between Mars and Earth. Mars is 142 million miles away from the Sun and, on average, 40 million miles away from the Earth. As they orbit the Sun, the distance between the two planets fluctuates. Riding with one of the fastest spacecraft developed by NASA, the New Horizons craft, it would take 162 days, ~304 sols, to reach Mars at its average distance away from Earth. At its farthest point from the earth, it would take 289 days, ~542 sols.
4- Every place Watney visited on Mars is real. Weir did thorough research of every place Watney went. I speculate this should be the reason why the book won NASA’s vote of approval, and eventually the movie was made with NASA’s endorsement. For example, Watney, along with his other crew members, initially landed in a large northern basin on Mars, called Acidalia Planitia. This is where the crew established their home base, “the Hab”, and where Watney spent most of his time.
5- While the above are very much based on real science, Weir made the beginning of the story rather fictional than scientific. Watney became a stranded astronaut on Mars because he and his crew encountered a severe dust storm on Mars. This dust storm was the source of all the troubles that Watney had to deal with, alone, for the next 583 sol days on Mars. Does this dust storm have scientific legitimacy? The answer is NO; this dust storm is purely fictional. The atmosphere on Mars is about 1% of earth’s air density, so a storm on Mars wouldn’t have enough force to blow a steel rocket ship.
Besides learning and validating real science, I also enjoyed that Weir wrote The Martian as a true earth citizen. The rescue effort was finally a big success because it engaged a globally united effort. Weir recognizes that global collaboration defines the future space program. With that belief, Weir let China National Space Administration (CNSA) also play an important role in rescuing Watney. Initially a NASA rocket carrying supplies to Mark Watney would do the job but it exploded during launch. At this most critical moment, CNSA offered to provide a rocket booster to NASA. This Chinese rocket, Taiyang Shen, laden with supplies, successfully completed its journey to Mars, and in return NASA awarded a seat to CNSA on their next Mars mission. Although this scene would currently be impossible in reality, I share Weir’s hope that we may learn something from his book, and move forward with the goal of cooperation in science, technology and space exploration for humanity.