Finally got to see the movie last night. What’s to say that hasn’t already been said up-thread; only that I thought physically clicking the pen off of Kristen Wiig’s forehead to demonstrate the MAV launching was comedic genius.
In addition to what carnivorousplant and ElvisL1ves said, there’s also this:
So now Ares 4 is stuck delivering for Ares 5, and don’t get to land themselves.
It’s clear that the original Ares mission plan is fubar owing to the need to recover one astronaut, which again illustrates a dramatic limitation of crewed exploration using marginal technology and resources, i.e. the need to bring astronauts home at planned end of mission versus leaving a probe or rover in place to operate indefinitely and without recovery. The rescue effort itself is exciting and inspiring, but like the Apollo 13 mission, it ends up reducing the scientific yield specifically because of the limitations of people as instrument carriers.
The more I consider them, the more the MAVs (as portrayed in the movie, at least) are problematic. They clearly aren’t designed to withstand reasonable worst case environments (never mind even the highest winds on Mars would not impose enough load to topple an otherwise stable structure). In-situ fuel synthesis may have been a baseline in the novel but in the movie there appears to be no equipment or power to synthesize fuel nor a descent downstage separate from the ascent first stage, so it appears that it carries its fuel down and then for the ascent. This is possible and one of several possible mission architectures, but requires essentially the same propulsive and mass ratio performance as an Earth-launched single stage to orbit (SSTO) vehicle. (We don’t have any details about descent so it is possible that it used an aerobraking decelerator rather than fully propulsive descent and just propulsion for a final targetted landing.)
In that case it doesn’t make a lot of sense to pre-stage the lander and hope that it will function after several years on surface, but of course this is necessary to make the story work. It’s a pedantic nitpick in a film that hews much closer to realism than anything produced by Michael Bay or Roland Emmerich, but it the story is contrived to make the rescue possible, whereas there might be any number of other developments which could prevent it regardless of any effort or be immediately lethal to Watney.
Stranger
BTW was that a Delta Heavy I saw launching at the end?
Yes, and an Atlas V that failed during the first resupply launch. I guess Elon didn’t want to pay for product placement to get the Falcon Heavy in there.
Also, nobody in mission control cheers just after liftoff. It’s a collective breath-hold all the way through fairing ejection and payload release, and in fact, sphincters don’t unclench until the insertion parameters are confirmed as nominal.
Stranger
In the book, Andy Weir states that for every pound of hydrogen you take to Mars, you can make something like 13 pounds of fuel using elements on Mars. According to the novel it takes 2 years to make enough fuel to fill the tank so the MAV needs to get there early. As mentioned above it’s the job of the Hermes to land it on the surface. The RTG that Watney digs up to keep warm in the rover was originally used to power the refuel operations for the MAV - it get’s buried by the crew on arrival for their own safety. The movie did portray that there were 2 stages - an ascent and descent stage but only barely - it was the descent stage where he found the hydrazine which he used to make water.
It could be worse than that. Hermes is going to need some serious overhaul after what Ares 3 put it through, the bomb damage being only part of it, so they’ll have to wait, probably years, just for the flyby. Unless NASA launches 2 MAV’s and a load of fuel for at least one of them, so the Ares 4 pilot can land them both from orbit and the crew can use one and the fuel to perform their own mission.
Speaking of the Hermes damage, didn’t the book mention that the bomb took off the aerodynamic nose? The film Hermes was obviously incapable of re-entry (maybe they used an Orion to bring crew up and down, like a Soyuz to the ISS), but was that the mission profile in the book?
Hermes in the book was designed for aerobraking, for capture into orbit at Earth and Mars. The entire thing would have been conical and designed for aerodynamic travel. It was also intended that the entire thing would spin, rather than having a gravity wheel, possibly after separating into two pieces connected by cables or struts.
So, in the book, they’re all gonna die, from shooting off into space instead of entering Earth orbit, or from burning up trying. Good thing the last chapter was still back over Mars. 
But Rich Purnell has a year and a half to figure something out.
They have the ion engine. They just have to start slowing down earlier to get back into earth orbit.
They could do that anyway, with or without the aeroshell. So, why the aeroshell then?
Yes. I think I read somewhere the footage was from the Orion launch (Exploration Flight Test 1) last year. This was the unmanned test flight of the Orion capsule which is designed to support human spaceflight to the Moon and beyond.
If you’re like me, you don’t like reading a book version of a film after watching the film, but I would encourage people who enjoyed the film to go ahead and read the book. It’s chock-full of readable technical details that help explain a lot. Plus you’ll see what happens during that seven-month period they jumped over.
Books are generally better than films.
Best out of context quote in a long time…
Loved the book. It’s been a long time since I’ve had my hands on a page turner like this. I picked it up for a camping trip and it was awesome to have on hand during the rest and relaxation.
The mission commander mentioned that they were committing “mutiny.” Dramatic license, or actually true? Do NASA astronauts swear oaths, or are they legally-bound to obey lawful orders from NASA superiors? The commander and the pilot were said to be “Navy,” but I assume that’s “former Navy,” given the separation of the U.S. military from the civilian space agency.
NASA is a civilian agency. Although members of the military may be seconded to NASA for astronaut or other duty, they’re not under military authority in regards to their duty to NASA management. Technically they can be held accountable for violations of the UCMJ but I can’t think of a particular violation that would occur other than conduct unbecoming or some similar conduct violation. “Mutiny” is a general is a rebellion against lawful authority of a ship. Given the extraterritorially of interplanetary space it seems unlikely that NASA or the US government could do anything more than terminate employment and (maybe) pursue civil suit due to damages, but I don’t think any criminal proceedings could be justified.
Stranger
That mad lady astronaut (“diapernaut”) from a few years ago, Lisa Nowak, was Navy and then returned to her parent department and then cashiered.
So there is precedent.
Yeah, the commander said specifically that she and Martinez could be court-martialed. How realistic is that do you think?