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Comment by Jare | Hacker News Reader

I would say Ad Astra is filled to the brim with fantastic and implausible elements. The visual design is very realistic, and this contrast adds to the movie's sense of disconnect (which is great it you like it, and a movie killer if you don't).

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If we are talking at implausibility, Gravity is filled to the brim with it. It does a very lousy presentation of orbital mechanic: you don't point at a general direction of space station which is 70km away, give an impulse away from it and slowly drift to it. It is not how it works!

On top of this implausibility, the criteria in the parent post was ‘there’s no “supernatural” element whatsoever,’ which given the heroic ghost of Kowalski‘s role in saving the protagonist (as a “hallucination”), should also rule it out. Never mind that the film was essentially disorienting scenes and Sandra Bullock repeatedly shouting into the cameras

Hallucinations aren’t supernatural. Kowalski wasn’t a ghost. This was evident in the movie.

The Martian’s bad physics and chemistry should also rule it out from the list based on your criteria. Which would be sad, because despite that, it’s a great movie and book.

Book chemistry and physics (other than dust storm) looks rather plausible, what didn't you like there? Movie added some ridiculous stuff when flying with punctured space suit, that was pathetic.

Why not? What's inaccurate about it?

Objects in space in adjacent orbits around aren't floating in space, they are falling on Earth at a great speed. If you apply an impulse in the way as shown in the movie, you'll expand or shrink the orbit excentricity and you will likely start moving up or down rapidly relative to your target, instead of closing in. This way to get to your target you'll need to burn an insane amount of fuel and do orbit corrections every second. The right way is to make one impulse to change your orbit in such a way that your new orbit will intersect the orbit of your target (and that you both will be there at the same time), and the direction of such impulse might be far from obvious. More likely one impulse will result in a very long transit orbit, so a better course would be two or more orbital corrections.

Ah, that makes sense, thanks!

So is The Martian. The physics in the movie and book are absolutely magical: windstorms powerful enough to impale people but not enough air pressure to require a top to the spacecraft. Toxic, perchlorate soil growing potatoes… Both the book and movie are wonderful, but have huge gaps of implausibility.

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