Inside the Spaceflight of 'The Martian'

benonemusic writes: Science writer Michael Greshko partnered with a team of scientists and engineers to explore the spacecraft and mission plans in The Martian (novel and movie), down to the rescue plan itself. Incorporating the help of Andy Weir, the novel's author, he comes up with a calendar of events for The Martian, explores the hazards of going back to save Mark Watney, and explains how a real world interplanetary spacecraft would pull off a rescue maneuver.

Comments

Are and storms that fierce on Mars?

[peter303]

I know they have sandstorms, sometimes dense enough to hide the surface. But with an atmosphere that never exceeds 2% the density of Earth's, can it blow people down and topple spaceships?

Re:Are and storms that fierce on Mars?

[ClickOnThis]

I know they have sandstorms, sometimes dense enough to hide the surface. But with an atmosphere that never exceeds 2% the density of Earth's, can it blow people down and topple spaceships?

The short answer is no.

Re:Are and storms that fierce on Mars?

[SharpFang]

Andy Weir explained in one of the interviews that it was the only point where he used his artistic license against hard science. "I wanted Mars to deliver the first punch". He said he could have done this differently, but he wanted this to be Nature's fault, not a human shortcoming.

He stayed true to science best to his ability the rest of the time. Not that he didn't make any mistakes - he made quite a few, but none of them were intentional violations, just his lack of universal knowledge - or developments that happened after he wrote the book.

To name a few:
- water content in soil, making Hydrazine burning moot.
- Chlorides content in soil, making it totally unsuitable for plants and harmful to health, unless purified.
- raw potatoes being merely "awful" while in reality they are quite poisonous.
- hydrazine reaction heat being neglected (someone calculated it would heat up the Hab to 400C).
- space radiation being handwaved away by "Hab is radiation-proof" while it's an inflatable structure.

Re:Are and storms that fierce on Mars?

[Irate Engineer]

- raw potatoes being merely "awful" while in reality they are quite poisonous.

Wow, they sell 5 lb bags of raw potatoes in the store! What a reckless thing to do! Amazing the personal injury lawyers haven't jumped on that!

Seriously, properly grown potatoes are harmless, raw or cooked. However, being nightshades, if potatoes are not hilled properly the ones near the soil surface that are exposed to sunlight will turn green and produce solanine, a glycoakaloid poison. I grow potatoes in my garden and just make sure to toss any potatoes that have any green on them.

Fresh young potatoes from the garden, sliced thin and sprinkled with a little sea salt are pretty darned tasty, but eating nothing but potatoes would start to suck ass pretty quickly.

Re:Are and storms that fierce on Mars?

[Rei]

It is apart from solanine. Potato starch is indigestible raw. It passes all the way into the intestines intact, where it then begins to ferment under the influence of anaerobic bacteria. This yields significantly less caloric energy as well as indigestion and bloating.

Anyway, Weir wouldn't have had to worry about potatoes greening (solanine) because he had at least 2-3 orders of magnitude too little light to actually grow potatoes, thinks that the entire part of the plant above the soil is the "fruiting body", and thinks that potato mounding involves completely burying the plant and planting new potatoes directly on top of it. Not to mention the perchlorates, ethylene gas, or the 50 other things that would have actually killed his potatoes if grown as described. (Note to anyone who's ever owned a winter greenhouse or done significant indoor plant growing: expect to repeatedly hit your head against the wall if you read The Martian).

Oh, and try not to think too much about his plan of having humidity condense on the habitat and rain back down as a method for watering the plants (sensitive life-critical electrical systems and condensation: best friends 4everz!). It's bad enough when it happens in your apartment... I remember the day when my light fixture fell to the floor and broke because it had filled up with water and become too heavy to support itself - sure explained the reason why the breaker to that room kept throwing! At least in the movie they seem to have added a grow tent, judging from the trailer (haven't seen the movie yet). Although grow tents bring their own problems... and most clear plastic sheeting is polyethylene, which is a pain to bond.

Re:Fun Movie, Not Future Reality

[SharpFang]

Not entirely impossible, just unlikely. There was a lot that could go wrong, and very likely to go wrong. The deceleration through blowing the airlock would most likely send Hermes spinning instead of decelerating, the opening not being a precise nozzle but a random hole directing the air outside at a random angle. The rocket would most likely be unbalanced after such heavy strip-down, sending it spinning again.

OTOH everyone overestimates the "one chance" they had at the encounter.

You're moving 12m/s away from the target.
To reach 12m/s at 2mm/s^2 you need 6000s or 100 minutes. That puts the target at 72km distance.
Now give it a chase. Accelerate for half of that distance, decelerate the other half. 6m/s top speed, average 3m/s relative speed. That's another 6.6 hours.
Mark would need to spend about 8 hours waiting for Hermes to smoothly make a perfect rendez-vous after failing the initial encounter. There's no time pression of time like with suborbital trajectory - they are both on escape trajectory. Hermes would get a little off Purnell Maneuver trajectory, but 72km offset and 12m/s error is practically nothing for this kind of mission. The whole panic was simply unnecessary.

Re:Fun Movie, Not Future Reality

[Quarters]

Thanks for being the self-centered asshole who feels it's OK to fire up his phone screen in a darkened theater. Why should you have to bother to park your selfishness for 90-120 minutes and let the scores of other people see a movie in peace, right?

Re:Fun Movie, Not Future Reality

[RoccamOccam]

I just watched this tonight with a lady friend. I was bored enough to browse /. on my phone for a little while. Then she grabbed my hand and whispered that I'm supposed to be watching the movie.

Wow - you just casually admit to this? For the sake of others, please never do this again. There's a reason that theaters run the little public service announcements about turning off your phone before the movie. This should be a standard question on a test designed to identify sociopaths: "If you bored while watching a movie in a theater, do you a) suffer silently, b) leave the theater, or c) ignore the rest of the people in the theater that have paid to watch the movie and pull out your phone."