Gravity Kills: Comments on the Movie from an ISS perspective


I finally broke down and saw Gravity yesterday.  I was a bit reluctant to see it, because having worked in Mission Operations for 14 years, I knew that any technical inaccuracy would jump out at me.  It’s hard to lose yourself in the moment when in  the back of your mind you know that the color of the walls is off and the sign in the background is pointing the wrong direction.  But, I wanted to give it a chance.

Gravity is highly entertaining and it is a beautiful piece of motion picture art.  Director Alfonso Cuaron will likely do more to promote the existence of the International Space Station (ISS) and the Chinese Space Station (CSS) than anything that I will do in the course of my career.  Sandra Bullock was great in the lead role and I’ll happily add this to the list of movies I want my girls to see when they get a little older.  I enjoyed George Clooney’s character and appreciated the way he approached the character.

Was the film an accurate reflection of the real world?  It was hit and miss.  The inciting incident of the movie was inspired by a real-life event that has caused ISS many headaches over the years.  Some other minor details were great – the auroras, the inverted image in the water bubble, an accurate Station Support Computer (SSC) and Portable Computer System (PCS) in the ISS – but many other things were not.  I’d like to give a little insight into how some things really work, not in an attempt to tear down the movie, but more to educate on how things really are.   The frustration I have is that many of these could have been written into the movie without changing the narrative or changing the art and had some of these things been corrected, I would have spent less time focusing on the background details and more time immersed in the story.

I’m not going to address the biggest issue – Hubble, ISS, and CSS being in the same orbit and within line of sight – that’s already been done, nor am I going to harp on the worst moment of bad science when Clooney’s character floated away.  I’m also not going to address the shuttle, the spacesuits (EMUs), the Soyuz or the CSS, I have little to no expertise in each of those.  My friend and co-worker Michael Interbartolo III is quoted in this CNN article addressing some of the shuttle issues. Instead, I’m going to focus on ISS and some of the realities of ISS operations.

Let’s start with the Soyuz. (And Mr. Clooney, it’s pronounced ‘soy-yous’ not ‘soy-yez’. You needed to channel your inner Philadelphian and repeatedly practice saying ‘yous-guys’ to help get it right.) The Soyuz is the lifeboat for the ISS; however, there is no extra. We always have enough Soyuz craft available to bring the ISS crew home and that’s it.  The movie gave the impression that the ISS had a 3-person crew and an extra Soyuz capsule to come home in.  The ISS should have had 6-crew and 2 Soyuz, each capable of returning 3 people to Earth.  Rather than having an extra lifeboat, they could’ve easily written into the script that half the ISS crew was killed, after all the ISS had already taken a bit of a beating.  I recognize you needed the Soyuz for the narrative, it’s just too bad they didn’t do it in the confines of reality.

Ms. Bullock enters the ISS via the Russian Airlock when in reality she would have been more familiar with the US Airlock.  The Russian Segment set pieces looked great and made me wonder if the Russian Space Agency cooperated with them more than NASA did, which would explain their prominence in the film.  When she doffs the spacesuit, she should have been wearing a Liquid Cooling and Ventilation Garment although that would admittedly have been less..uh… visually appealing.

Not as attractive as a tank top and short shorts.

This is admittedly nit-picking, but these are the elements that really make a story convincing and immersive.

Now, the other big thing from an ISS perspective is the sudden raging inferno that forces our hero into the Soyuz.  My job for five years was to come up with fire cases like this in order to test the capabilities of astronauts and flight controllers.  Week after week, I and my fellow instructors would come up with devious, loosely plausible emergency scenarios that our tortured students would need to correctly address.  It was the most fun part of the job.

It was also incredibly challenging.  The engineers who designed and built ISS did a great job mitigating the risk of any potential fires.  ISS is built with materials that are designed to either not catch fire or not propagate a fire.  ISS oxygen levels are carefully regulated to ensure that the oxygen concentration stays below a certain level to reduce the risk of a fire.  The ISS is also extremely compartmentalized so that if a fire does start in one area, it won’t spread beyond that area.  In addition, when a fire does start the ISS immediately shuts down all fans and closes ventilation valves wherever possible.  This does two things. First, it stops feeding oxygen to the fire. Second, it stops toxic byproducts of the fire from spreading to other modules.  All of this means that a huge fire a la the one in Gravity was highly unlikely if not impossible.

Now, there are two things that are known fire hazards that could have made the situation more realistic.  There is an oxygen system, containing 100% oxygen, in the US airlock.  Astronauts receive special training on handling this system, because an incorrect action here could result in a catastrophic explosion.  If Bullock’s character had plugged something into this system, like say to recover from a mild case of decompression sickness from her spacewalk, then you could have done it easily.  Either that or the ISS does have a solid fuel oxygen generator, the same system that caused a dangerous fire on Mir.

So the fire as it occurred was unlikely, but there are ways to retcon it. The little detail I wish they had gotten right though was the fire extinguisher.  If memory serves, Ms. Bullock grabbed a fire extinguisher in either Node 1 or Node 2.  She should have grabbed a US fire extinguisher, instead she had what looked like a Russian fire extinguisher.


The orange ovoid is a US fire extinguisher.

The US fire extinguisher contains compressed carbon dioxide and it is propulsive, which means the little jolt she receives when firing it and thereby almost knocks herself out would have been correct if she had been using the right extinguisher.  The main difference between the US and Russian extinguishers – the Russian extinguisher discharges a sort-of soapy water instead of a gas.  Again this isn’t a big deal, but it is a detail they could have easily gotten right and not changed anything to do with the story.

The last  thing I have to address is the training aspect.  A shuttle payload specialist would almost never have been trained on the Soyuz. The only shuttle crew that I’m aware of receiving Soyuz training was the crew for STS-135.  Post Columbia accident, a protocol was enacted where the next Shuttle to launch would serve as the rescue vehicle for any shuttle that was damaged on launch or in-orbit.  With 135, that wasn’t possible.  So the plan was if the shuttle had been damaged, the crew would stay on ISS as a safe haven and mix in with the ISS crews in returning to Earth.  It would have taken us almost two years to fully return that 4-person shuttle crew to Earth if that had happened.  Because that was the rescue plan, they received some special Soyuz training.  However, they would have sat in the Soyuz right seat.  That crewmembers doesn’t have much more of a role than a living bag of sand.  They would have received no Soyuz pilot training.  No US astronaut has ever been trained to be a Soyuz pilot.  It’ll never happen.  I would have easily believed her if she had said she crashed the shuttle simulator, which I have had the pleasure of doing myself.

In the end, Gravity was highly entertaining and a gripping movie experience that looked absolutely fantastic, but it was much more space fantasy than it was hard science fiction. There were more issues than what I’ve detailed here, but I think I’ve beaten this horse enough.  I’ll happily share this movie with my girls when they’re the right age and I’ll enjoy it for what it is, but if you’ve read to this point you’ll have a little better understanding for how some of these things should have worked.