# Forgotten on Mars: exploring the journey of Mark Watney from the Martian movie

Original author: Jeffrey Bryant
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Jeffrey Bryant's " Stranded on Mars: Exploring Travel on Mars in The Martian " post .
thanks to Kirill Guzenko. KirillGuzenko for help in translating and preparing the publication.

Not so long ago, according to the popular book The Martian (Martian) Andy Weir , a film was made that was released on October 2. Martian- A film about the astronaut Mark Watney, left alone on Mars. The crew of Ares 3, the third manned flight to Mars, believed that he died during the evacuation. The crew during the flight took with them only the basic means for salvation and communication. The next manned flight to Mars was supposed to take place four years later, because Watney had to either come up with a plan for survival during this period, or reconcile and die. The book perfectly presents various technical details about the conditions and means available, as well as about the problems that arise as a result of using various things not for their intended purpose. And these details give us a great opportunity to explore the adventures of the protagonist with Wolfram language.

I think now is the very moment when you need to write: CAUTION, SPOILERS! From this moment on, various aspects of the storyline, its moments and turns will appear and be investigated in the article. And if you would not like to know now some details of the plot, then I would recommend reading the book first, and then returning and reading the article.

Moving and connecting with NASA are some of the most important issues Watney is facing. He decides to remake the abandoned rover for longer journeys to get to the nearest communications point - the Mars Pathfinder landing site . The book indicates the coordinates of the main base of Watney, which is called habitat (habitat - lit. transl.), Or briefly - NAV. To visualize the area around Ares 3 NAV, I used Mathematica10.2 (which contains high-resolution embedded images of Mars) and GeoGraphics :

To view this area at a greater distance, you can use the GeoRange and GeoProjection functions:

The distance from NAV to Mars Pathfinder can be calculated as follows:

The Watney path can be visualized using GeoGraphics :

After Watney found the Mars Pathfinder and made a connection, he began planning his own evacuation. Due to the nature of the Ares mission, the Martian take-off module (Mars Ascent Vehicle, or MAV for short) arrived long before the next crew arrived (a way to leave the planet). That is, the crew of Ares 4 will be only in four years, but their MAV is already in place. The problem is that the MAV of Ares 4 is located at another point in Mars - in the Schiaparelli crater.

Quite far from NAV Ares 3 - more than two thousand miles. It turns out a much longer trip than before the Mars Pathfinder:

In fact, it is still more complicated. Due to craters, valleys and other obstacles, the path will deviate from a straight line. One of the first deviations of the path is in the Martian valley (Mawrth Vallis).This is a water-carved valley that connects the relatively flat Acidali Plain (upper left in the figure below) with the more massive, higher-level and crater-strewn Arabia Terra (lower right in the figure below):

Although the path through the Martian Valley forces one to deviate from a straight path, however a smaller angle of elevation in this section will facilitate the path. We can take a closer look at the Martian Valley using the GeoRange function :

In the CDF file attached to this post (which can be downloaded from the link below), if you click on the picture and press the "." Key, then moving the cursor over the picture will display the current coordinates (latitude and longitude). In addition, by clicking on the picture, you can set a number of points, on which then the trajectory through the Martian valley will be built. After the path is laid, we can simply paste the resulting array of points. I also rounded the resulting values ​​to 0.01 angular degrees - this is about half the pixel in the figure above. Now let's create a trajectory along these points with the help of GeoPath :

Holding the path to the Schiaparelli crater, Watney passes by various geographical objects, some of which he gives his own names. For example, an area that is limited by cratersBecquerel, Trouvelot, and Marth, he called the "Watney Triangle." Or, to quote his speech from the book: “I will call it the Watney triangle, because after what I went through, this Martian crap just has to be called in my honor.”

Considering all the data indicated in the book, we can get a rather detailed picture of Watney's trajectory and of the areas that he visited: The

actual distance traveled deviated strongly from the straight line, so that the real distance was greater than what we calculated for a straight trajectory. By combining all points of Watney's trajectory, we get that he actually had to overcome 300 miles more than he would go in a straight line:

But the story does not end there. After Watney reached MAV Ares 4, he still needed to get to Hermes - a large spaceship used to transport astronauts between Earth and Mars. Due to the fact that Hermes uses ion engines, he cannot quickly change his speed, and because of sharp changes in plans, he has no way to enter the required orbit. Watney is faced with the task of flying with the help of MAV, which is designed only to reach the orbit, to the altitude at which Hermes will fly at the point of minimum distance from Mars, and which significantly exceeds the calculated height. The proposed solutions to these problems are almost as intimidating as the problems themselves. I enjoyed reading the book. Mark Watney faced with a lot of challenges that had to be overcome in order to survive.