Question: Why did they have to use a bomb to blow out the door to slow the Hermes for the rendezvous with Watney? Wouldn't simply opening the door have the same effect?
raywest
24th Mar 2025
The Martian (2015)
Answer: From Internet sources: The crew blew the airlock hatch to change course and rendezvous with Mark Watney after he launched himself from Mars. This was done to overcome a critical situation where the crew lacked sufficient fuel to travel to Watney and the be able to return home. The blasting air venting into space would propel the ship forward while saving fuel.
From my take of the movie, they blew the hatch to slow the Hermes to more closely match Watney's speed, not propel it forward.
Yes, they blew the front airlock, so the thrust would be aimed against their travelling direction. It may be confusing if you are not used to the idea of 'braking' with counter-thrust.
9th Oct 2023
The Martian (2015)
Question: After 400 days, the stranded astronaut's original, on-board, food ran out. After that, he lived on just potatoes for two or three more years (or something like that). He says, himself, "I have to grow three years' worth of food." The only food he grew was potatoes. Starch only - no lipids and no protein. For two or three years, to live on just potatoes? Is that even physically possible?
Answer: I've seen the movie a few times, but did some additional Internet research. Watney was spreading out his 400 days of rations with the potatoes. I seem to recall him opening a small packet of a powdery substance and putting it on his food. Presumably it was vitamins, minerals, or other supplements. Of course, he was still severely malnourished when rescued.
Answer: The book explains it a bit more in depth. He had vitamins, minerals and supplements for six people, and NASA supplied enough for each person for a year, just in case some were damaged or spoiled... so he had plenty of vitamins. However, you can't live on just vitamins; you still have to have food... namely the potatoes.
8th Jan 2021
The Martian (2015)
Question: Would it really be possible to make water using the method Mark Watney uses in the movie?
2nd Aug 2018
The Martian (2015)
Question: Mark says he will have to get to the crater, which is 3200 kilometers away. Mark says he has one working rover, designed to go a max distance of 35 kilometers, before the battery has to be recharged at the hab. During the nighttime scene, he says he has doubled his battery by scavenging Rover 1, but if he uses the heater he will burn through half his battery everyday. I did some math, and worked out that the max distance his rover would be able to go without using the heater would only be about 140 kilometers. How would he travel 3200 kilometers to get to the crater?
Answer: Mark says he has 1 Rover that can travel 35km before recharging. He estimated he would need to travel for 50 days to reach the Ares IV site (down to approximately 22 days when not using the heater, as per your maths). Mark is shown using the solar panels (stolen from the Hab) to recharge the Rover during his journey. He drives for 4 hours before noon, waits 13 hours for the Rover to recharge to full and then starts driving again.
Answer: He wouldn't need to use the heater because he salvaged the Radioisotope thermoelectric generator (RTG) and this also saves his power.
11th Oct 2015
The Martian (2015)
Question: Is it realistic that Mars vehicles like Mark's rover or in some scenes his handcart would use rubber tyres? No Mars rover before used them and I would think they could not stand the low Martian atmosphere and temperature differences.
Chosen answer: Whatever was used before on Mars is irrelevant as to date, only robotic vehicles have been used. As this is depicting how humans would live and function on Mars, the vehicles would be designed quite differently. Presumably, the "rubber" tires have been specially manufactured to withstand Martian conditions. Mostly likely they would be solid and not have an inner tube filled with air or some other gas that is affected by the atmosphere.
Answer: Airlocks have two doors - open door 1, get in, close door 1, change atmosphere inside airlock, open door 2, get out. It's a built-in safety feature that only one door at a time can be open. As they couldn't overcome it, they had to blow out one of the doors while the other was open.