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Mars Movies Entertainment

Inside the Spaceflight of 'The Martian' 124

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.
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Inside the Spaceflight of 'The Martian'

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  • what we see are the shadows on the screen.
    • by umghhh ( 965931 )
      Better than what this old fart Plato had. Now we can share our shadows on the wall of the cave and see it all while drinking beer and eating popcorn.
  • by peter303 ( 12292 ) on Saturday October 03, 2015 @08:23PM (#50653829)
    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?
    • by Anonymous Coward

      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?

      You're not watching a science documentary. So a little bit of artistic license is good.

    • by ClickOnThis ( 137803 ) on Saturday October 03, 2015 @08:40PM (#50653897) Journal

      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. [popsci.com]

      • But, presumably, when the air is filled with sand it is a lot denser than standard Martian atmosphere. They do not appear to account for this change in atmo density, so I am not sure about their calculations.
        • That's an effect, but unless you increase the viscosity of the (saltus, 'a leap') grains don't stay suspended for more than a couple of seconds once the turbulence drops even for a small amount.

          If you look at rock pedestals [google.co.uk], then their most severe erosion is strongly at the base. Compare the images with a more typical pyramidal hill to get the difference in erosive force between base and top.

          Preventing landed craft from over-tipping with such a strongly concentrated low-level force is a job for outriggers [google.co.uk]

    • by Jhon ( 241832 )

      If you are in low gravity, you can pick up much heavier objects and throw them at your friends. Getting hit with a 1 lbs rock will do less damage than getting hit with a 100 lbs rock -- gotta love how mass works.

      Is there enough wind to MOVE huge rocks and people in space suits? Not really. But explosive decomp in lower gravity could possibily toss a 180 lbs human out the door and a decent rate of speed. And if there was a sudden stop (slamming in to a cliff or another habitat module), that could be pret

    • by SharpFang ( 651121 ) on Saturday October 03, 2015 @09:30PM (#50654099) Homepage Journal

      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.

      • by Irate Engineer ( 2814313 ) on Saturday October 03, 2015 @10:29PM (#50654269)

        - 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.

        • Well, a tested method in the army here, to get a few days off e.g. missing some heavy exercises, was to eat a couple raw potatoes. Guaranteed heavy diarrhea and a bit of fever.

          They aren't so poisonous as to "eat one and you die" and I guess a few slices surely won't hurt, but a few potatoes eaten raw just cause a severe indigestion. I believe it's completely apart from solanine, simply human digestion is incapable of dissolving any bigger pieces of them properly.

          • I have eaten raw potatoes plenty. Never had any poisoning or anything. It is the green that kills, and the potato is not green unless you left it in the sun.
          • by Rei ( 128717 ) on Sunday October 04, 2015 @06:27AM (#50655287) Homepage

            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.

            • It's not *that* bad - he used electric lighting and the solar farm was much bigger than Hab, so consider sunlight->electricity->light used that way a kind of lensing.
              His plan to condense moisture was silly but it wouldn't come to it with the water reclaimer and the dry soil acting as a sponge. Never mind any running electronics would be warmer than the walls exposed to near-vacuum on the other side, meaning a plenty of condensing surface long before the electronics would be endangered.
              But yeah, he'd f

              • by Rei ( 128717 ) on Sunday October 04, 2015 @07:37AM (#50655467) Homepage

                Yes, it is that bad. And he makes it even worse by boasting about how "incredible" the efficiency of the "super-efficient" panels and then giving it a terrible efficiency, something in the ballpark of 11% if I recall correctly. And then states that the panels are at a fixed tilt (with the "scientist" protagonist not understanding why they'd choose a particular angle... *snicker*) - so they're not sun tracking. Combine this with Mars's low solar constant. Combine this with the dust that he says he has to keep wiping off the panels. Combine this with the not-all-that-impressive panel area to begin with. Combine this with the maybe 20-30% efficiency you might get in producing PAR with a good LED grow light. Combine this with the fact that these are not grow lights, but rather the normal room lighting built into the habitat (white phosphor = loss of energy). Combine this with the fact that anyone who thinks you can grow caloric crops on normal room lighting is a moron, regardless of how much power you have available to you.

                I can break it down with exact numbers for you if you want, but I'll just sum it up for you: it's 2-3 orders of magnitude off, and that's assuming that there's no bottleneck of how many lights the habitat was built with, which would actually probably bottleneck it to 3-4 orders of magnitude off. To people who've never grown caloric plants without sunlight, they can be forgiven for not understanding how vastly much energy it takes. Trust me: it takes a *ton*. The sun at Earth imparts about a kilowatt of light per square meter. Per *square meter* - and that's light, meaning to reproduce the sun, you have to use several kilowatts per square meter to account for the losses. Think of how much power an efficient light bulb consumes. Now think of how many of them you need to use to equal a kilowatt of power consumption. And how much of your light you lose to straying.

                You have a few things going for you. The sun goes down at night. The sun isn't always high overhead, so you have cosine scaling. So you don't have to produce as much energy as the above implies. But it's still a mind-boggling vast amount of light to need to produce across a very large area. A very good yield of potatoes (which contrary to his claims, you absolutely will not get in his situation even if you had sufficient light - going into why would be a longer post than even this one) - is about 50 tonnes per hectare per year, or 5 kg per square meter per year, or 11000 calories per square meter per year, or about 3-4 days worth of calories for our anything-but-sedentary protagonist, meaning a farm area of about 100 square meters. If one assumes that the reduced solar output caused by sun angles and night to roughly compensate for the energy losses to convert electricity into light and the amount of light that strays, then you need about 1kW constantly per square meter, or 100kW, to match the energy input from the sun. That's the power consumed by 80 average houses in the US. Not like his hab would have 100kW of lights just built into it....

                It's easy to forget how intense of an energy source the sun is, and how much energy it takes to keep a human going.

                The thing is, had the author not been totally ignorant about plants (despite making his main character a botanist... a botanist that somehow nonetheless seems disgusted by manure ;) ), there are ways one could have reasonably written in a doable scenario. But botany is one of the many, many things that Weir totally bungled in the book.

                • Give the habitat spotlights from Rover 1, spotlights from MDV, spotlights from Hab's outside lighting and all the spare bulbs for everything.

                  The solar panels are hindered by fixed angle and distance from the Sun, but boosted by equatorial latitude and thin atmosphere not dissipating nearly as much light as Earth. Although yeah, 11% is lousy. Let's assume space technology of 2035, and give them a healthy 65%, blaming the 11% on Mark being a botanist.

                  Remember, individual care of individual plants, optimal tem

                  • by Rei ( 128717 )

                    Are you really incapable of doing the math?

                    A LED headlight is something like 30W. Times 2 for two of them. Times three for "super ultra powerful Mars headlights even though an actual Mars mission would be about saving power". Times 4 for "all of the other things you mentioned". That's still only 720W, what you might use to light up a single square meter.

                    Don't you get it yet? You simply don't "scrounge up" enough light bulbs to grow an entire person's diet worth of food. It's an impossibility - unless you

                    • sh1t, did some serious math, then accidentally closed the tab.
                      First, 1KW light output is if you want Earth's equatorial sunlight, which is far more than plants need - they saturate their input at far less than that. I arrived at 500W (input) of LEDs to produce the needed output for 1m^2, and about 2.5m^2 of solar panels to power them up.

                      Still, obtaining the needed lamps - yep, 1m^2 per spotlight, 12 per rover (per movie), 10 from other sources, Hab lighting for another 4 or so meters... weaker sources focus

                    • by Rei ( 128717 )

                      First, 1KW light output is if you want Earth's equatorial sunlight, which is far more than plants need - they saturate their input at far less than that.

                      Yes, one has to incorporate a "capacity factor" to account for angles, night and clouds. Something like 15% would be typical for potato-growing regions. But at the same time, when light is coming from LED lighting, you have to account for stray lighting (light that's not hitting your grow area) and efficiencies at generating PAR, which are 20-30% for proper

                    • Not even close. Your solar array too has a capacity factor - in the ballpark of 15% if fixed, maybe 35% or so if tracking. Then you have your panel efficiencies. The best large scale commercial panels are 22-23% efficiency. You might get 30%-ish if you used absurdly-crazy-expensive spectrolab cells. Then factor in dust constantly settling on the panels - say 25% loss even with regular cleaning. And Mars's solar constant is only 588W/m^2 *in space*. Earth's is about 1kW/m^2 *on the surface*, 1,4kW in space.

                      I

                    • One thing more:

                      But at the same time, when light is coming from LED lighting, you have to account for stray lighting (light that's not hitting your grow area) and efficiencies at generating PAR, which are 20-30% for proper grow lights, lower for normal room lights (as the phosphor wastes part of the light energy to make it a comfortable white rather than a painful pink).

                      Did you account for PAR fraction of sunlight? LED growth lights have a significantly better PAR coefficient than sunlight - which covers mu

                • by Reziac ( 43301 ) *

                  He didn't do too well on the microbiology either. Being freeze-dried doesn't kill an awful lot of bacteria; it just makes 'em encapsulate until conditions improve.

      • - hydrazine reaction heat being neglected (someone calculated it would heat up the Hab to 400C).

        Yes, if the calculation assumes a completely adiabatic Hab, and the heat release occurs quickly. A trickle of hydrazine in a Hab in contact with the ground with ambient temps around 0 deg. C doesn't seem farfetched to me.

      • by steveha ( 103154 )

        - space radiation being handwaved away by "Hab is radiation-proof" while it's an inflatable structure.

        At least the story is internally consistent: because the Hab is radiation-proof, radio waves don't go through it, which is why Mark Watney has to go outside the Hab just to check his email. (Actually, I think he ought to have strung a network cable; he cheerfully did more difficult tasks than that at various points in the book. But then the plot complication caused by going outside so often might not have

        • by Rei ( 128717 )

          At least the story is internally consistent: because the Hab is radiation-proof, radio waves don't go through it

          Yet another Weir misunderstanding, confusing all forms of radiation as if they're the same thing. If you want to block radio waves with as little mass as possible, you use metals. If you want to block streams of charged particles with as little mass as possible (the actual goal), you use hydrogen-rich materials, ideally with a borated inner liner. Weir has a history of misunderstanding radiation

          • by Rei ( 128717 )

            Clarification on radiation shielding: you generally don't use just a hydrogen rich layering, there may be metallic layers as well (such as the craft's outer skin, tankage, etc). But most of the high energy solar and GCR is charged particles, mainly protons. The lower end of the energy range will almost entirely impact whatever shielding you use, creating a small shower of secondaries. Some high energy particles will impact, some will pass right through. Those that pass through will most likely pass through

          • don't products of decay of Pu-238 create all other kinds of radiation than Alpha? With it sitting there for a couple years, there would be quite a few...

            • by Rei ( 128717 )

              Nope - it decays to 234U, which has a 246k year half life and is also an alpha emitter. There's some minor spontaneous fission in 238Pu, which can produce basically whatever, but the spontaneous fission half life is 4,77e10 years, which is dwarfed by the alpha half life of 87,77 years. There's also the potential for the occasional alpha side reaction, but the cross sections are extremely low.

          • by steveha ( 103154 )

            He's not "joking around", the rant is like a page and a half long, describing it as vastly more dangerous than Pu-239, with a long line of superlatives for how to describe its incredible "danger".

            Either you and I have very different ideas about what Andy Weir wrote, or else your copy of the book is different from mine. Since mine is an ebook, I can search it, and the string "239" has zero hits in my copy of the book.

            Here's what my copy says:

            ...[NASA] never used large RTGs on manned missions until the Ares

            • by Rei ( 128717 )

              You cut short the rant. The full rant is:

              Well shit.

              I came up with a solution, but remember when I burned rocket fuel in the Hab? This’ll be more dangerous.

              No, it would in no way, shape or form be. NASA technicians mess assembling probes and rovers do so without any special radiation precautions, just precautions against burning themselves. NASA technicians do not burn toxic hydrazine inside enclosed spaces that they're breathing that they can't ventilate.

              I’m going to use the RTG.

              The RTG (Radioi

              • by steveha ( 103154 )

                Seriously, how can you read this tripe without wanting to hit your head against a wall? How can you call a novel that has this sort of nonsense and does almost every single chemistry equation wrong "hard science fiction"? Does anything that spouts pseudoscientific BS qualify as "hard science fiction" these days?

                IMHO you are being too hard on the book. In the book, the things Watney does are plausible solutions to problems that make sense to me.

                Andy Weir said he didn't want Watney being "hit by lightning" o

              • by steveha ( 103154 )

                You know, it occurs to me that you probably quit reading the novel at the worst possible place. You are so qualified to spot mistakes with chemistry and indoor gardening that you were repeatedly outraged and stopped a quarter of the way through. You missed on the later parts where the problems being solved had nothing to do with chemistry and indoor gardening.

                I read an article where a couple of orbital dynamics guys said that Any Weir got the orbital dynamics stuff basically right; I've read multiple comm

      • by Rei ( 128717 )

        There were far more major glaring errors than that. I managed to read about a quarter of the book, needing something to bang my head into on almost every page. No, I don't want to turn this thread into yet another "rip on the terrible 'science' in The Martian" thread, so I'm not going to start yet another "list" like I've done the last times the book came up on Slashdot.

        Honestly, with how much he screwed up the science in general, I doubt Weir's "I did it for artistic license" excuse about the dust storm. I

      • by drsmithy ( 35869 )

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

        No they're not, I eat them regularly and have for 30+ years.

      • by umghhh ( 965931 )
        I know this feeling - something is outrageously wrong and you want to tell the world about it. Believe me I have experience with this - this is pointless. It is a nice flick nothing less or more(*). I tend to get this surges of anger too - I sit and write an essay for myself only and list all things that are wrong. Most often though I find that the most annoying parts are not omissions, errors and some such - they are stories where humans hardly play a role or/and which are inconsistent internally. No SF c
    • by Agripa ( 139780 )

      To borrow a phrase from Niven's "How the Heroes Die":

      The sandstorm was at the height of its fury, which made it about as dangerous as an enraged caterpillar.

      http://www.e-reading.club/book... [e-reading.club]

  • I'd like to watch it when does it become available on VOD services so I can buy and watch it online?

    Still can't find a date anywhere...

    • unlikely to be soon - too early after cinema premiere. BTW, for the story, read the book, it's vastly superior. For the visuals go to 3D theater, they made Mars beautiful. Home-viewing quality of the movie is the worst of both worlds.

    • by KGIII ( 973947 )

      As I posted up-thread, it's not worth seeing at home in my opinion unless you've a *very* good setup. There's little redeeming value other than the eye candy and good acting. It is marginally better than above average and that's only due to seeing it on the big screen. I don't expect it to do well once out of the theater unless they add some compelling content. (I do wonder if it would make an interesting video game, however.)

    • by tlhIngan ( 30335 )

      I'd like to watch it when does it become available on VOD services so I can buy and watch it online?

      Still can't find a date anywhere...

      You need a date? You can consider in general, a movie hits VOD around 3 months after first premiering. Or probably closer to two months after its off first run status and the cheap theatres get it. This frees up the good prints for other regions.

      Movies that have particularly good runs that say in first-run status for a long time will be delayed longer. But 3-6 months is typi

  • Ever since 1977, when a little movie called Star Wars caught the public’s attention, the space opera has been the go-to subgenre for mainstream movie sci-fi. There’s room for other takes, like Duncan Jones’ 2009 cult hit Moon or this year’s excellent Ex Machina, but those are usually tiny films that play at the edges. When it comes to big studios and big budgets, it’s all about action and sweeping melodrama (with a little futuristic dystopia thrown in from time to time) —
  • how a real world interplanetary spacecraft would pull off a rescue maneuver

    Well, for starters, they wouldn't leave someone behind who wasn't dead and buried. "Dead" in the sense of "injuries incompatible with life" and/ or "failure to revive" and/ or "decomposing". This has been established by long history of mountain, cave and other remote area search and rescue incidents. If you want a ball-shrivelling account of how hard it can be to tell, read Joe Simpson's "Touching the Void" (the film wasn't too bad e

    • This has been established by long history of mountain, cave and other remote area search and rescue incidents.

      Wait what? iirc the path up to the summit of Everest is littered with bodies of climbers who couldn't make it. Including one who was reportedly injured but alive for several hours. Other climbers talked to him as they passed, but there wasn't anything they could do as attempts to help would just result in both of them dead.

      • Yes, they knew where he was and couldn't (or wouldn't) do anything to help him. But they knew where he was. The big difficulty, particularly for people who are intending to help, is if you can't find someone who you think is missing, or if you think someone is missing, but don't know they are missing. Or in the cave rescue scenario, you know someone is in a cave somewhere within walking distance of here, but you have to thoroughly search every one (including the unexplored or un-published ones), when there
        • Everest isn't a good example of normal mountaineering

          I suspect that Mars isn't a good example of standard operating procedure for mounting a rescue either.

    • In the book (haven't seen the movie yet), the storm slammed a piece of metal into Watney's suit and into his body. He was knocked unconscious, so he was unresponsive, and IIRC they couldn't see his body immediately. The instruments in his suit were damaged, and so his telemetry was gone. It was a crisis situation. People will leave an unburied colleague behind in those circumstances, if they think him or her dead.

      • Wait - hang on. The wind was sufficiently powerful to pick up an item of mean density 3 or 4 tonnes/ cubic metre. and "slam it into" something of mean density about 1+a-bit tonnes per cubic metre which wasn't moving. I don't know about you, but when I last got picked up by the wind, my ice axes (metal and GFRP ; they sink, I float) stayed laying on the ground because they were denser than me. (My rope also held, which is why I was using a rope.)

        Oh, sorry, I'm forgetting that the "left behind on Mars" is a

        • It's a way of leaving Watney behind that seems maybe plausible if you don't think about it. That's the best I can say about it. It does explain why the rest of the expedition might leave without verifying his death.

          In Earth's atmosphere, it is possible for wind to drive solid objects through others, but it typically takes a tornado. I have no idea what sort of wind would be required for the Martian air to do that.

          • It's a way of leaving Watney behind that seems maybe plausible if you don't think about it. That's the best I can say about it.

            That's not a lot to say, really. I prefer my sf to engage my braincell a bit more than that. Well, I'll probably see it at some point, but I can't say that I'm motivated to actually go out of my way (e.g., to a city with a cinema, or to log onto the wife's DVD library website to book it) for it. I'll see if the copy of the book turns up on the recreation room's library. Frequently t

            • Unfortunately, since I haven't seen the movie, I was talking about the book. It's probably more accurate, but it is disappointing when a hard SF book starts off totally fudging something. I'll probably see the movie Sunday.

              I swap tweets from time with a guy whose signature line was "There is a robot on Mars. I give it instructions, and it does what I tell it to do."

              Cool!

              • Niven, of Ringworld, once wrote that he likes to keep his SF to no more than 6 impossible things per story, because much more than that allows you to get the protagonists out of any scrape. The "with one mighty leap, he was free" syndrome. So, faster-than-light travel at 3 LY/day (subjective), plus ageing-retarding "boosterspice" makes for a more interesting "universe" than infinite velocity and infinte lifetimes. An unbreachable protective shield ruins wars, unless it needs someone on the outside to turn t
  • What about that? For me, that was the weakiest idea in whole movie. Almost vacuum outside - 0.6 kPa (0.6% of Earth's atmosphere pressure), lowest possible inside (if pure oxygen): 56 kPa. Hole diameter about 2 m, which gives 176 kN (or more easy to imagine 16 tons of Monty Python's sudden weight)...
  • Wow...I do hope that slashdotters realize that this was a MOVIE...FICTION. Geez...it's not Star Wars, which really was scientifically accurate, down to the ability to vulcan mind meld. oh...wait. Wrong movie. oops...Beam me Up!

"I got everybody to pay up front...then I blew up their planet." "Now why didn't I think of that?" -- Post Bros. Comics

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