68

Because he would need to make an airtight seal between the walls of the Hab and the ground. What is shown in the movie is that the Hab is a prefabricated 'tent', and Mark shifts a significant amount of Martian rock dust into that space through the airlock and makes soil that can support a potato by adding "biological materials" and water. In this scenario ...


54

Normally, no, you could not grow plants in Martian soil... but adding nutrients to the soil makes it perfectly usable. There's a great article about it on Modern Farmer: And, yes, it is possible to grow plants on Mars—kind of. Alone, Martian soil doesn’t have the necessary elements for plant life. “The main thing that’s not in Martian soil is a bunch of ...


30

The question on the potatoes was directly addressed in the book. They gave the most calories per area of farm land. Couple other points where you appear to have miss interpreted/remembered some details. The hab is not sealed to the ground. When they got there they laid out the floor materials, staked them down, attached the canvas for the sides and top, ...


26

Watney was on the Ares III mission. Missions up to Ares V were in the works, and equipment such as the MAV (Mars Ascent Vehicle) were already in place on Mars, waiting for these missions to arrive. The amount of equipment necessary for each mission was split into separate launches to reduce the individual payloads. Shortly after Watney discovers he's ...


25

The reason they don't look at the Ares 3 site is that they don't want to get an image of Mark Watney's body which they would have to release to the public (since NASA is a government organisation it has to release all its images to the public). After two month they finally take a look because they hope they can maybe start an additional mission which can ...


25

The physics of Mars in The Martian is identical to the actual physics of the planet, as such, we only need to know the actual length of a Martian sol (in hours/minutes) to know how it compares with an Earth day. A Martian day is nearly identical to an Earth day. There's only a difference of about 2.7% between the two. The average length of a Martian ...


21

He didn't. He used the hydrazine tanks from the MDV (Mars Descent Vehicle) - emphasizing that the descent vehicle is completely separate from the MAV (Mars Ascent Vehicle), which is what the crew used to leave at the beginning of the film. Like the MAV IV (which Watney used to leave Mars), the MAV III had been sent in advance of the mission to create fuel, ...


20

I interpreted it as the first day for Mark in his new mission of training future astronauts. This also has nice symmetry with the Sol count, since Sol 1 was the first day on Mars and therefore the start of the Mark's mission on Mars. I think this ties in nicely with the new plant because it is basically a new beginning/phase/chapter in Mark's life. Also the ...


18

It is not until late in the movie that they discover he is still alive. It's not late at all that they discover that he is still alive. They discover this in a few weeks (Sol 54 - about 2 months) - when they see that stuff has been moving around on the base. By Sol 109 (just over 3 months) he has got Pathfinder and is communicating with Earth. This all ...


17

First, the degrees being too narrow is a non-starter. The stick he uses for the 22 degree markers provides the accuracy, and a wider circle would compensate for the smaller, 13 degree sections. And the Pathfinder Lander (renamed the Carl Sagan Memorial Station) IMP (Imager for Mars Pathfinder) would absolutely be able to accurately match any arbitrary degree ...


14

While there are several vessels available to both Mark and the Ares III crew, there are a number of reasons why the 5 crew of the Ares III mission couldn't just land and get Mark Watney: The remaining crew are aboard the Hermes. The Hermes doesn't have the Thrust to Weight Ratio (TWR) to either land or launch from Mars. Hermes is designed to travel vast ...


14

Because he lacked the resources to start over. All the plants/potatoes were dead from lack of oxygen and sub freezing temperature. The bacteria in the poop soil as well. And his source of fuel that he could turn into water. So he had nothing to plant, in soil that was sterilized, with no water to sustain it. The potatoes are no longer suitable to plant, ...


13

No. According to Bustle (The interview was a press Q&A on set): "I talked to [Director] Ridley about [losing weight for The Martian] because I’ve lost weight before for movies," Damon told Newsweek. "We had about six months. And I said, 'That’s perfect. I’ll lose about 30 or 40 pounds, and we’ve got to shoot all that stuff first.' And he went, 'Fuck ...


12

After reading an answer to the exact question on Science Fiction & Fantasy Stack Exchange (as pointed by Richard), it became very clear why hexadecimal is the better system to communicate with. The reason has little to do with the number of slices in the circle, but mainly with the pre-agreed upon protocol of communication. You see, using a decimal ...


12

In the film, there's a scene between Kapoor and Sanders, immediately before Park receives the message from Kapoor, which explains the situation (covering much of the novel information from Raidri's answer): The Ares 3 mission was scrubbed a little past half of the way into its projected 30-sol time frame due to the storm, so it was largely a waste. Mars ...


11

Disclaimer: Answer according to the book, not sure if it is the same in the movie. The whole process happens in two steps: Burning the hydrogen directly as it is produced from the hydrazine in the normal 20% oxygen atmosphere. Mark does this until he notices that not all hydrogen is burned and the concentration in the hab atmosphere gets up to 60% hydrogen....


11

Saving water He has limited supplies of water. Of course he hasn't showered in his entire 561-Sol stay - it's possible (and in Mark's case necessary) to maintain hygiene while spending much, much less water than a shower does.


10

Does anyone question how much a Seal Team 6 rescue mission actually costs when they go and rescue a captive from terrorist hostage-takers, let alone protest it? I've never seen it. Perhaps you could link some examples, specific to my scenario, of a backlash that amounts to more than a handful of fringe nut-jobs to back up your assertions. If NASA was able ...


10

As explained in this answer: Shortly after Watney discovers he's stranded he mentions the Ares IV MAV is already on-planet, though it is far away - much further away than the buggy can take him. Needing to reach the Ares IV mission site (where the Ares IV MAV is already) is what prompts him to start retrofitting the buggy for longer journeys. ...


9

Then... what? Even assuming they could seal the docking door again It was an airlock door. Airlocks have two doors. They opened one and breached the other. The one that was just opened can simply be closed. The airlock will just not be functional afterwards. (side question: why did they have to blow it up, couldn't they just open it normally?), ...


9

Exactly distance unknown, but likely somewhere between 464.634 miles and 600 miles. It's not directly spelled out in the film. However, in Chapter 8 of the novel, the following discussion takes place: “Watney’s on the move again.” ... “Still going in a straight line,” Mindy said, pointing to her monitor. “I see,” Venkat said. “He’s sure as ...


9

The communication delay was in fact addressed in the movie. Here is a link to the scene with Director Ridley Scott's commentary. Around 3:25 Tim makes a sarcastic comment about the limits of the communication with Mark, including the delay. "Are you receiving me?" "Yes. No." [Vincent] Okay, point the camera at "yes."...


9

The Hermes is on a slingshot around Mars, it doesn't enter an orbit. They are arranging for the MAV to launch to meet its speed as it makes its one fast pass around the planet. After they maneuver to intercept Mark the velocity (between the Hermes and Mark) before they blow the airlock was around 40 m/s (130 ft/s). Beck says that he can catch and hold ...


8

It's a little open to interpretation, but I took it to be somewhat different than Erik did: it's Day 1 for this new class of would-be astronauts. Mark's graying hair and easy comfortable presence int he class seemed to be meant to imply that he'd been teaching classes for quite some time by this point, but for these new hopefuls, this is Day 1 of their ...


8

Why did they send the MAV to Mars so early? The core answer is: The MAV needs time to make fuel. The MAV is pretty cool. Turns out, through a neat set of chemical reactions with the Martian atmosphere, for every kilogram of hydrogen you bring to Mars, you can make thirteen kilograms of fuel. It's a slow process, though. It takes twenty-four months to ...


8

The Martian was classified as a Comedy by HFPA because the Hollywood Foreign Press Association’s eligibility committee voted to make it so. According to the LA Times the HFPA vote was very close as The Martian ended up classified as a comedy by just one vote. Without specific comments from those who voted it would be nothing more than speculation to ...


8

Because they skipped details from the book. In the book he has two duplicate rovers. He uses the second one for spare parts and as a trailer that is towed by the first rover (in the movie he just uses a flatbed trailer). The second rover has to carry life support equipment that doesn't fit, so he has to cut it open. - reddit.com I have not read the ...


8

The hexadecimal system would only use 2 "bytes" per character. With the decimal system there could be letters or symbols requiring 3 "bytes" per character. If you want to avoid confusion and add a 0 in front of characters requiring 2 "bytes", you effectively add 50% to the communication compared to the hexadecimal system. Plus, since Johanssen has an ASCII ...


8

The movie character, Vincent Kapoor, was originally Venket Kapoor, and fully Indian in the book of the same name. The casting of Chiwetel Ejiofor required a slight change on background of the character, otherwise keeping the history intact. Ridley Scott has not answered any questions on why the casting and changes were made, even when criticized for "white-...


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