To grow potatoes one needs, at the very least, nutrients, water, sunlight and carbon dioxide.  Mark Watney (played in the movie by Matt Damon) decided to make 600 liters of water, to water his potatoes, by decomposing a rocket fuel, Hydrazine, to get hydrogen gas.  He then burnt the hydrogen with oxygen (that he got from carbon dioxide recovery system), to make water.  Empirical formula of hydrazine is: N2H4.  Catalytically decomposing one mole of hydrazine gives you 2 moles of diatomic hydrogen gas (H2) and one mole of nitrogen (N2).  Hydrogen can be then burnt with excess of oxygen to produce water.  Approximately, how much hydrazine is needed to make 600 liters of water that he figured he needed to water his potato plantation?  Hint: paraphrasing Bill Clinton 'It's the stoichiometry, stupid!' :-); this calculator may help: http://goo.gl/kMUPxQ

In the movie, the astronauts in their spacesuits have their faces illuminated by the lights inside the helmets, which I believe is for the benefit of the camera.  Briefly describe, using your knowledge of optics, why this may not be such a good idea.  Hint: the following simulation may help to figure it out: https://goo.gl/une6nc                                               

On the Hermes spaceship, far away from planets and stars, there is little gravity, and there is no force that prevents you from floating up in the air.  Yet the astronauts seem to walk and sit normally as soon as they get to one of the compartments attached to the 'gravity wheel'.  Assuming that the wheel's radius is about 20 meters, approximately how fast does the wheel need to turn (with how many turns or revolutions per minute, rpm, it needs to rotate) for the astronauts to feel the same acceleration due to gravity in their living quarter on the wheel perimeter as they would on earth, which is some 10 meters per second squared?  Hint: this calculator may help: https://goo.gl/7w1Ufu

Mark Watney, stranded alone on Mars, lost all means of communicating with the mission control on Earth.  He found an old unmanned Pathfinder Probe that NASA lost on Mars, and brought it to life.  All the probe could do is to take still images and move its camera around.  Mark figured that it can use the camera to rotate and point to the letters and numbers placed on a circle around it, to send and receive messages.  The problem was that there are 26 letters in the English alphabet, and if you add 10 digits and other signs, there is hardly enough space on the circle to place them all there and point to them reliably.  So he resorted to hexadecimal number system that has only 16 characters, which can be accurately pointed to by the camera.  A set of two such characters can be converted to as many as 256 different signs (do you know why?).  Using the ASCII table above, figure out what were the messages sent to Mark by NASA.

When Mark blows up the airlock (and loses all his potatoes plantation as a result), he cracks his helmet, and start suffocating while losing air from his pressurized spacesuit.  Imagine that inside the spacesuit the pressure is 1 atmosphere and the the crack in his visor has 1 cm^2 area.  What's the approximate force that the air inside his spacesuit pushes on the ductape stuck over this 1 cm^2 hole? Hint: you need to look up what the pressure on the surface of Mars is and compare it with atmospheric pressure on Earth, for example here: https://goo.gl/UJdZQa and here: https://goo.gl/wvoQzc

In the movie's final sequences, NASA's control center speaks freely with the Hermes spacecraft, near Mars, in real time.  That's an obvious exaggeration - it takes time for the radio signal, travelling with the speed of light in vacuum, to go that far.  Can you figure out how long does is take for the radio waves to travel to Mars and back in reality?  Hint: you need to use the speed of light in vacuum and the distance between Earth and Mars to calculate it.  Note that the distances can vary greatly: Mars and Earth are close to each other when they are on the same side of the Sun, and much further apart when they are on the opposite sides.

Mark Watney mishaps start from a terrible 150 km/h dust storm that rips off the antenna from the building, which in turn impales and nearly kills Mark, makes his astronaut buddies take off, and left him stranded on Mars.  Everything else being equal, the drag force of the wind is more or less proportional to the density of the atmosphere and to the square of the wind's speed.  The density of the Mars' atmosphere is about 100 lower than the density of the Earth's atmosphere.  What would be the speed of wind on Earth that would be equivalent in force to the wind on Mars depicted in the film?

Mark dug out an old, but still active, plutonium thermoelctric generator to heat the cab of his Rover.  The generators like this are real and work by converting the heat of decaying Plutonium 238 into electricity via a thermocouple (remember?).  Decaying plutonium not only generates heat but also very harmful ionizing radiation that is lethal to mammals.  Read these two short articles: https://goo.gl/7Szt1X and http://goo.gl/PhioFj and figure out why Mark was probably safe with decaying plutonium 238 behind his drivers's seat.