A Real-Life Space Botanist Comments On the Potato Garden In 'The Martian' (cnet.com)

MarkWhittington writes: In the hit movie, The Martian, stranded astronaut Mark Watney famously survives on Mars by creating a potato garden using Martian soil mixed in with composted human excrement. According to a story in CNET, NASA believes that the movie is on the right track as far as astronauts growing their own food on long-duration space missions. However, some caveats exists concerning how the film depicted space agriculture.

Comments

MST3K

[CajunArson]

If you're wondering how Matt Damon eats or breathes, and other science facts.
LALALALA

You should remind yourself it's just a show I should really just relax.

Re:MST3K

[Rei]

It's scientifically accurate in that "it's possible to grow plants on Mars, just not in the way done in the movie and certainly not in the way done in the book".

As for the way done in the movie:

But those nitpicking details could be crucial in real life.

The biggest problem, he said, is that Mars is about 1.5 times farther from the sun than the Earth is, and only gets about 60 percent of the light. This means that plants on Mars would grow at about 60 percent of the rate of Earth plants, even when exposed to full Mars light. Watney's habitat was designed to block radiation, which would lower the light levels even more.

"How would he get enough light for his plants? He didn't go into that. But plants need bright, bright light," Bugbee said. "We normally use a lot of solar panels and a lot of electric lights, but one of the things we're working on now is fiber optics: big, concentrating mirrors and fiber optics to bring that bright light in to grow plants."

Not to mention that the room, as shown in the movie, can easily be calculated to be significantly too small even if it was getting Earth light. But at least the situation in the movie (one order of magnitude too little energy to sustain a person) is better than in the book where potatoes are being grown on normal room lights ;) Most people don't realize how much vastly dimmer it is, from an energy perspective, inside than outside - our eyes compensate for it, otherwise you wouldn't be able to see details in bright areas and dim areas at once. But that little "nitpicking detail" - 2-4 orders of magnitude too little light, give or take - is indeed critical to plants growing, and especially to them producing energy to store that humans can eat.

Had Weir had any experience whatsoever with growing caloric plants indoors, he would have realized this and there are many things he could have done in his design to ensure that the plants would get enough sun. The best option is exactly what the actual botanist above mentions: solar concentrators. A solar thermal power plant is a perfectly plausible way to generate electricity on Mars and Watney - had he been given a solar thermal farm and habitat with lots of transparent plastic - could have redirected heliostats to reflect large amounts of light into the habitat and stripped off insulation (adding it back on every night) to compensate for the dramatically increased heat load. That would have thus avoided the solar to electricity losses and the electricity to light losses, giving an order of magnitude more power, as well as avoiding the need to have quantities of lights onboard hundreds of times brighter (and correspondingly more power-hungry) than you actually would ever find. And it's plausible he could have taken existing heliostats and aluminum scrap and significantly boosted their parabolic area and thus light output (assuming the drive mechanism could take the additional load or he could modify it to).

But, that's not how it went.

There's tons of other things that would have killed the plants grown as described in the book (getting caloric crops to grow right in sealed spaces indoors is difficult even in controlled circumstances, there's such a huge range of things that can suddenly and dramatically wipe them out - which is why, as mentioned in TFA, NASA has a whole department researching the topic to try to create the controlled conditions to prevent this), but let's just stick to the most fundamental aspects here for now. The light was, pardon the pun, the most glaring problem. ;)

Re:MST3K

[Wahakalaka]

Unlike a lot of other "science fiction" books/stories, Andy Weir seemed to make a genuine effort to get as much right as possible, and did his best to drag along the film producer. If all of science fiction was at this level, it would be a miracle. And as you've pointed out, where the science does fail, it fails in such a way as to spark discussion and interest in the real science. I don't feel like my intelligence was insulted after having watched/read it, or that errors and omissions were a result of laziness or "the audience is too dumb/doesn't care anyway, so why bother". (Although the book was better than the movie in that regard.) If anything it served as a launching (punnnns) point for learning more about growing food on Mars and other similar problems.

space pirate, ARRRRRRRR!

[Thud457]

I'd be more interested in his take on maritime law.

Re:Sigh

[Major Blud]

A few years ago I saw a comedian on TV who was talking about watching Dr. Doolittle with his wife who happened to be a lawyer. When Dr. Doolittle's wife offered to defend him in a court case, the lawyer wife said "That would never happen in real life, the court would never let a spouse represent a defendant". The comedian responded with "Did you miss the part 5 minutes ago where they had a talking alligator?"

Re:What part of Science Fiction do you not get?

[Baron_Yam]

>My favorite example was "Gravity" where orbital dynamics where simply ignored wholesale, mainly because what would take weeks/months/years to develop in reality, needed to happen on much shorter time frames for the sake of the story. If you liked the movie, I'll bet you didn't notice this the first time you watched it.

I gotta tell you, my grasp of orbital mechanics is at Kerbal levels, but that was enough that it ruined major portions of Gravity for me.

It would have been better if the movie (like Interstellar) hadn't been promoted as scientifically accurate when there was obviously no real intention to make it so.