Gravity is an enthralling, beautifully shot film with strong performances, especially from Sandra Bullock. The set designers show an impressive eye for realism. The writers do not.

It's best to view Gravity as a daydream or fantasy. It's entertaining. In fact, it is exactly the kind of story I used to sit and imagine as a kid, on long flights across the Atlantic.

The story unspools like a what if? daydream in which the daydreamer got their full understanding of space exploration by watching CNN. A central mindset is the lack of understanding of three-dimensional space and the scale of the Earth.

The story begins with the crew of the Space Shuttle Explorer performing repairs on the Hubble Space Telescope (HST). Clooney is a very experienced astronaut on his last flight and Sandy, although called a mission specialist, is more like what we used to call Payload specialists. She says she only trained six months for the mission. That would never happen for an EVA crew member, but okay. She also says she is a medical doctor but her purpose for being on this flight is to install hardware she designed on the Hubble Space Telescope. Not sure how that works out.

During that EVA a missile destroys a Russian satellite. That satellite debris hits other satellites, destroying those satellites. CapCom, in Houston, calls the Orbiter crew and tells them to abort because the debris is a threat to them. CapCom also tells them that the debris is going to take out the communication satellites, so contact with the ground will soon be lost.

This debris comes along and strikes the Orbiter and Hubble, destroying the Orbiter, leaving only two EVA crew members alive.

Here's a zoomed out 2D view that shows the scale of the orbits of the TDRSS (Communications satellites), the Hubble, and the ISS.

The blue circle represents the Earth, there are two small circles just around it - the ISS at around 400 km and the Hubble at around 560 km. Outside of that is a larger circle representing geosynchronous orbit - the location of the TDRSS.

And here's a side view, although not to accurate size scale for the TDRSS orbits.

There's an unfortunate line in the film where CapCom says the debris is headed up to their altitude. Let's just pretend he didn't say that, because it doesn't make any sense at all.

Now look at those two diagrams and try to imagine the orbit of the debris such that it will destroy the TDRSS and intersect the orbit of Hubble. Remember that orbits must pass through the center of the Earth.

Anyway, so our two crew members decide to use an MMU nitrogen powered jetpack to fly from the location of Hubble to the ISS, which Clooney's character points at and says it is about a 100 km away. There are two possible points in the orbit where Hubble and the ISS can be as close as 150 km apart - the two points where their orbits overlap in the side view. And, since Hubble and ISS do not travel at the same angular rate, the odds of both being at that point at the same time are pretty small. They are also moving in different inclinations, so they would only be that close for a few seconds.

Clooney calculates that the debris will return in about 90 minutes, based on its orbit. That means it is orbiting in LEO - which again raises the question of how TDRSS got taken out.

Anyway, they start heading towards the ISS - pretty impressive given that the real MMU had a range of about 150 meters. Also pretty impressive because for the real last Hubble repair flight, NASA analyzed whether the Orbiter itself could get from Hubble to ISS if they were to find damaged tiles on the Orbiter, and the answer was no. We almost didn't do that mission because of that.

This is where the orbital mechanics really falls apart. Not only do they head straight towards ISS, which any shooter can tell you is wrong - you aim ahead of your target, not at it. But orbital mechanics doesn't really work that way. Orbital velocity is dictated by altitude, so, for example, heading down towards the Earth will cause you to move faster in the forward direction. The maneuver that they needed to do would involve plane changes and altitude changes and would require a huge amount of energy.

Clooney keeps pronouncing Soyuz like it is a Spanish word. That's probably the Mexican director's fault. He also refers to the FGB as Zarya - an astronaut likely wouldn't do that. Zarya is only used by public relations and the general public.

They manage to get to the ISS. There's a lot of scrabbling over solar arrays which would likely electrocute the astronaut, but okay. Sandy also moves with greater speed and dexterity than would be possible in an EMU.

The ISS crew were ordered to evacuate, too. But there is one Soyuz left at the ISS. That doesn't make a lot of sense because the number of Soyuz attached to the ISS is always equal to the number of crew members divided by three. If one Soyuz left, there should still be three people on board. But there isn't.

The debris shows up and wipes out the ISS too. Sandy goes inside the ISS and removes her EMU (spacesuit). She does it rather easily (it isn't that easy) and we see that she is not wearing the liquid ventilation and cooling garment. Without that, she would have passed out from heat exhaustion during the EVA. Instead, she is just wearing a tank top and tight shorts. Sandra has amazing legs for a 20 year old, never mind a 49 year old, so I'm not complaining, but another blow to realism.

What Sandy wears while in her EMU

Notice the two laptops below her - the one on the left is an SSC (Station Support Computer) and the one on the right is a Russian Laptop. In another scene we see a US PCS laptop. All three have accurate screens on them (other than the flashing FIRE box). That's nice attention to detail.

While Sandy is in the ISS, there is a fire. That fire spreads way too fast, considering almost nothing on the ISS is combustible.

What real astronauts wear while in the EMU

Since her EMU is spent, Sandy puts on not a Russian Orlan suit (the suit used for EVA), but a Russian Sokol suit (the pressure suit worn inside the Soyuz).

Sandy uses the damaged Soyuz to head towards the Chinese Space station, which remarkably is also about 100 km away. Sandy says she crashed the Soyuz simulator each time she flew it. As a mission specialist assigned to a Hubble repair flight, she would never have received any Soyuz training, so I'm not sure how she managed to crash the simulator. Soyuz training is only given to assigned ISS crewmembers.

By the time Sandy gets there, the Chinese station is deorbiting. That's a months long process, but it happens in a couple of hours in this film.

So, to address the question - to anyone familiar with how space operations are done, the film is rather cringeworthy, but if you ignore all that and just go with it, it's a fun film and worth seeing.