Movie "Gravity" happens in reality?

[ThunderStorm]

I think this might had asked somewhere or even here million times but could not find here:
Will the space stations hit by small space junks often without escape?
Or even by meteorites?

[pluto]

The ISS does get hit by small debris quite often. You can see evidence of it in photos of the windows etc.
Pieces of debris which are deemed large enough to possibly cause a major breach are generally large enough to be tracked. When one of these larger objects is calculated to come within a certain unsafe distance of the station either they attempt to change the orbit of the ISS so that it will pass safely or, if it's too late for a manuver, the crew suit up and enter their Soyuz spacecraft, ready to undock and potentially deorbit, and wait until the object has safely passed. This has happened a few times during the life of the station.

What happens in the film could happen, though not in the way it is depicted. In the film a satellite in GEO is destroyed and most of its debris is all of a sudden crossing the orbit of the HST+Shuttle. You could do the maths properly but in reality it would take many hours for that debris to reach them, probably at least 10 hours, maybe a few bits sooner. And when it did reach them it wouldn't all be all together, the pieces would be very spread out - still very dangerous of course but it wouldn't have torn through them like shrapnel. In reality they would have plenty of time to safely deorbit.

I won't go into all the other things wrong with the way orbital flight is depicted in the film (like since when are the HST, the ISS and Tiangong 1 in even remotely similar orbits... wtf) but I will say that once I realised I needed to turn my brain off I did very much enjoy the visual spectacle of the film, and have a couple of more times since :)

[ThunderStorm]

Thanks for detailed explanation.
Assume the speed of debris same as bullets and small could not be detected beforehand, how do the space stations survive? (Assume the station build materials are strong enough?)

[pluto]

The space environment in low Earth orbit is well known so spacecraft, and especially long term spacecraft like the ISS, are designed to be able to survive relatively frequent small impacts.

Here's a PDF from Nasa which explains some of the protection systems: https://www.nasa.gov/externalflash/ISSRG/pdfs/mmod.pdf

And here's a story from NSF talking about some specific incidences of impact damage: https://www.nasaspaceflight.com/2014/07/iss-managers-evaluating-mmod-radiator/

[OICURMT]

Object down to 2" are tracked by the DoD and NASA...

NASA have a good website regarding what/how they track items.

http://www.nasa.gov/mission_pages/station/news/orbital_debris.html

[The_bluester]

There was only one part I could just not see my way past. Most of the time I could suspend my disbelief but when the time came to dispense with George Clooney's services they had to have him dangling perilously from the far end of something (At rest compared to Sandra Bullock) Only to "Fall" away on letting go. Selective gravity?

Makes me grit my teeth every time!

[Kunama]

Maybe he 'fired' his 'AFTerburner' and the gases propelled him like an attitude control thruster.....? That methane has a power all its own.....

[pluto]

hahahaha :rofl:

[markbakovic]

I enjoyed, once I was done shouting abuse at my television, looking up "all the bad physics in the movie Gravity" on the internets and chuckling heartily at all the cleverer-than-Hollywood commentators blogging up their lists of inaccuracies in the movie which neatly demonstrate what a fickle thing the human memory and perception system is (or how rarely bloggers check their facts). My personal highlight was "At the start of the film the Hubble is attached to the end of the robotic arm and the arm is extended straight up from the cargo bay: this could never work as the arm would bend when subjected to the differential loads of masses as large as Hubble and the Orbiter at different altitudes" - while the "myth is busted" I guess (they orbit at slightly different speeds), that actually doesn't happen in the movie. In scene 1 Hubble is attached to the Hubble dock in the cargo bay, and that person's brain invented them a movie-myth to be clever and bust, all on its own.

Sort of back on topic, though, there's a report somewhere that claims we're about 20 years away from a "space economy", ie a proportion of global commerce conducted purely within space: products/services provided from space to other parties in space, with no involvement of earthbound entities at all. Some startups are already identifying "tracking and/or neutralising space junk" as probably the first industry that will fit that description.

https://commons.wikimedia.org/wiki/File:Space_debris_impact_on_Space_S huttle_window.jpg
etc.

[AEAJR]

When I read about the various meteor showers we experience I wonder about the ISS and the satelites. They must be passing through these areas which means they could be getting hit.

We sit on the ground hopeful of seeing some big streak across the sky but for the orbiting craft these have to be deadly things that need to be dodged.

Or, is that not the case?

[pluto]

That certainly is the case, hence the need for the protective systems and procedures mentioned previously. However, space is big, to put it mildly, and even with all the objects flying around in all sorts of orbits the chances of a significant piece hitting the ISS, or something else manmade, without being tracked and avoided beforehand is fairly remote - although not impossible and there have been satellite deaths which have been attributed to impacts in orbit.