What didn't make sense about "The Martian".

Okay, the film's like eight years old now and there have been numerous articles about it, but none really go into very many of the problems it has. But this is a sufficiently nerdy place to try outlining them.

- The storm could not have carried that much force.

Most articles touch on this one. Mars' surface pressure is less than 1% of Earths. It has dust storms all the time, but the main problem they'd present is visibility. Even 100kph winds would not so much as raise a pebble, let alone jeopardize an ascent vehicle or impale an astronaut.

- If somehow your ascent vehicle IS about to blow over, the *worst* thing you can possibly do is launch it.

What's wrong with stakes and guy wires? Better than taking off, instantly losing the only thing that's keeping you stable and upright, and immediately tumbling and blasting into a hillside, or the ground. NASA doesn't launch rockets in a hurricane. For good reason.

- Non-organic potatoes are sprayed with a sprouting inhibitor. You can't plant them.

Given that they were sealed in transparent plastic, NASA would not have skipped this step. Okay, that's nitpickery. But this isn't:

-- Mars is 50% further from the sun than Earth is (inverse square law, anyone?) and the habitat's skylights are at best translucent. It's VERY difficult to believe the spuds got enough light.

- Retaining a full atmosphere of pressure over a two-metre diameter hole requires an extremely strong structure. Plastic wrap and duct tape won't cut it by, many orders of magnitude.

- You cannot achieve measurable delta-V by poking a hole in your glove. You just depressurise your suit and die without going anywhere much.

- You cannot lose 40m/s velocity in a massive ship by venting some of its atmosphere forward. The math doesn't work, again, by orders of magnitude.

- No competent crew would have mutinied and gone off on that rescue without a known, feasible mission plan. A course is not a mission plan. Incredibly difficult problems were only solved after they were committed. Not even one of those astronauts would have gotten their job if they were that irrational, let alone all five.

But even give all that, it's a fun movie to watch. But more as a kind of meditation and an appreciation of what we can do than as hard SF.