GRAVITY is the most realistic space movie ever. I mean, that Clooney guy looks just like me!

Actually I've been besieged with questions about what I thought about this movie ever since it came out. Just here at work at SpaceX last week, I was asked that question about a dozen times a day. I quipped that "What do you think of Gravity?" was becoming every astronaut's least favourite question, surpassing even "How do you poop in space?"

So, to help me deal with this onslaught, here is my more serious attempt at a movie review:

First of all, it's a great movie. The pace and story was definitely engaging and I think it was the best use of the 3-D IMAX medium to date. Rather than using the medium as a gimmick, Gravity uses it to depict a real environment that is completely alien to most people.

But the question that most people want me to answer is, how realistic was it? The very fact that the question is being asked so earnestly is a testament to the verisimilitude of the movie. When a bad science fiction movie comes out, no one bothers to ask me if it reminded me of the real thing.

media_camera Garrett Reisman (second from the right) with the US space shuttle Endeavour crew. AFP Photo/Bruce Weaver

The movie does an outstanding job of capturing what it is like to do a spacewalk - much better than any previous sci fi film. Having done three spacewalks myself, I can tell you - this is legit. The visual impact of having nothing but the glass of your helmet between you and the Earth is captured very well. (Although the Earth is a bit more sharp and vivid in the movie than the real thing. Plus there is almost always an interesting landmass to look at when in reality you spend most of your time looking down at a less-interesting ocean view.) Also, the movement and physicality of doing a spacewalk is rendered in a very accurate manner. The ease of starting a motion and the difficulty of stopping it in the vacuum of space is captured accurately in many scenes.

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It's amazing how many things Gravity gets right. When Sandra Bullock's character turns the two valves to shut off oxygen flow to the Soyuz - those are exactly the correct valves to turn. When she wants to command the orbital manoeuvring engine, the CKD, she pushes the correct button which is also labelled correctly. The interiors of the Soyuz and the International Space Station, are pretty realistic although the various modules are not the correct position.

And the danger of space debris is very real. During my first spacewalk, my partner, Rick, had to bring in a handle that was stowed on the outside of the station. When he got it inside he noticed a hole, about a millimetre in diameter, that was shot through the half-inch solid aluminium material by a piece of orbital debris. It looked like someone had taken a cocktail straw and shoved it right through the metal. He looked at me and said, "If that hit one of us…" There was no need to finish that sentence, since such an event would have been instantly fatal, although I pointed out that he is about 6'2" tall and I am about 5'5" so it was much more likely to hit him instead of me.

media_camera Garrett Reisman doing what he does best in May 17, 2010. Picture: NASA

Ironically, the fact that the movie got so many things correct made it very disconcerting for me when the movie did get several things completely wrong.

SPOILER ALERT! Stop reading now if you do not want key plot points revealed.

Yes, there are major violations of the laws of physics and minor violations of typical astronaut behaviour in the movie. The biggest error is that there is no way to go hopping from one spacecraft or space station to another so easily. It takes tremendous energy and careful planning to change orbits. For example, as was made so clear in the aftermath of the Space Shuttle Columbia tragedy, even with it's flight computer, a full tank of propellant and hundreds of people on the ground to support, there was no way for the crew Columbia to reach the safety of the International Space Station. You can't just look around and see another spacecraft and then get there by simply pointing in the general direction with some soft landing jets and a fire extinguisher.

media_camera Gravity screenwriter Jonas Cuaron (left) with actors George Clooney and Sandra Bullock and director Alfonso Cuaron. AP Photo/David Azia

Another huge error was - there was absolutely no reason for Clooney to sacrifice himself!!! Once Sandra caught him, he would be just floating there. A small tug on his tether would send him back to the space station. And as my wife put it, when you have a hold of George Clooney, only an idiot would let him go.

Of course, at the speed he was tumbling by her, there is no way she would have caught him in the first place. He weighs a few hundred pounds and his suit weighs a few hundred more. Try lying on a sheet of ice while a 500 pound weight goes flying by and then try to grab a tether attached to that weight while wearing a pair of gloves from a medieval suit of armour. Not so easy.

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Also, how was Clooney going to beat Anatoly's space walk record if astronauts apparently don't wear either a diaper or a cooling garment under their spacesuits? That would be one smelly suit. Although I have to admit, that Sandra Bullock looked much sexier in her tank-top and boy shorts than I did when I took off my spacesuit:

media_camera Garrett Reisman, left, a former NASA astronaut.

Yes, I could go on and on about all the things Gravity got wrong. If you put me in a Chinese spaceship, there is no way I would be able to figure out how to fly it home. An astronaut that took joy rides around the Hubble Telescope with a jet pack shouldn't even bother coming home. And a debris field in low earth orbit would never take out geostationary communication satellites.

But who cares?

All of these inaccuracies were done to help advance the plot or to add drama to the film which is exactly the artistic license we should be willing to grant the filmmakers. This is entertainment, not a documentary.

Recently, I was at an event where Neil Armstrong's son talked about his father's many wonderful qualities and one bad one - it was very difficult to watch a sci fi movie with his dad. He would complain if one instrument was out of place on an aircraft's panel. He objected to the catapulting of fighters off the Battlestar Galactica - it's not like they have to build up airspeed to get aloft - why not just plop them out the door?

With all due respect to one of humanity's greatest individuals, I don't want to be like that.

It's just a movie - and a very good one.

This article originally appeared on Forbes

Originally published as What an astronaut thinks of Gravity