The Short Answer
A space ship would actually never stop because it ran out of fuel in the first place.
Due to a complete lack of air resistance, any vehicle with an empty tank would simply continue to travel at the same speed until something blocked its path and caused a collision.
Rescue is next to impossible, as is survival beyond a few weeks.
Stranded In Space - What Happens When The Tank Runs Dry
This is one of those thoughts that keep me awake at night, despite the fact I am not a qualified astronaut, nor do I stand a very high chance of boarding a cruiser to the moon any time soon. Have you SEEN what Elon Musk is charging?!
Perhaps I’ve just seen Sandra Bullock undergo significant trauma in Gravity one too many times, but running out of fuel in space is a strangely regular fear for me.
Imagine: you’re drifting happily through the vast expanse of the universe, safe in the knowledge you’re on the right track. Whatever your mission is, you’re ready to complete it.
Then all of a sudden - a quick flash of red warning light indicates your fuel tank is running low. Dangerously low. How could this be?! This mission has been planned to the letter!
What would you do?
Scream and cry? Maybe that’s just me. It certainly isn’t something to smile about!
If you’ve forgotten what you learned in Physics class, you may be thinking… “What’s the problem here?
Surely they’ll just drift to a gentle stop and wait for a rescue mission to come and bring them some more fuel?
Surely they would have enough food to simply hang out until the cavalry arrived?”
That’s where you’d be wrong. Unfortunately, my friend, the media has once again misled you, and you’ve fallen for it hook, line and sinker.
Unlike on Earth, where a car will grind to a halt once the gas tank runs dry, there is no air resistance in space, nor any friction whatsoever.
As a result, there is also nothing to pull your ship to a halt once the jets stop burning.
You’ll simply keep traveling in the same direction, at the same speed, because the tiny little particles, gases and other various lights in space are far too small to possibly drag you back or reduce the momentum of your movements.
This is the reason that, primarily, most space vehicles will have their engines turned off for the duration of their flights - any movies or TV shows that suggest otherwise are inaccurate and encourage extreme fuel wastage!
Stopping In Space - Harder Than It Sounds...
A space ship’s engine is actually only fired up for a short period of time as they depart from Earth, and again in order to decelerate when re-entering the atmosphere upon their return.
Continuing to travel even when you’ve run out of fuel might sound like a financial dream come true, but it’s actually very scary - there’s literally no way of stopping the ship now!
Deceleration is the operative word here, as that’s how you would normally slow down or prepare to come to a halt in space.
It basically involves strategically firing a set of thrusters faced forward, which work to create drag and help you reduce acceleration.
Again, where cars have brakes that are very easy to deploy, it’s not quite as simple on a space ship, as timing and accuracy are everything in deceleration.
It’s very difficult to achieve, and re-entering our Earth’s atmosphere is perhaps the scariest part of space travel because of the chance for failure.
Hit it too fast and you’ll burn to a crisp as you re-enter at hundreds of thousands of miles per hour.
Coming in too slowly is also a problem, as you could miss Earth’s orbit altogether and completely bypass the whole planet, meaning your chances of re-entry are very slim unless you have the fuel to come back around.
Possible Solutions - Will I Survive?
So, now that we know stopping is impossible once you’re out of gas, what happens next? Will you survive this fate?
Given that it’s highly unlikely NASA would waste money on a rescue mission - by the time they launch someone, you’ll have drifted so far into space it would take years to reach you - the answer to this question is more grisly than you might expect.
Unfortunately, once you’ve left the Earth’s orbit, it’s highly unlikely and nearing impossible you’ll make it back without fuel, so anybody aboard that ship is going to die before the chance of rescue can even come close.
Like George Clooney, untethered and floating away forever, your ship will simply continue to travel through interstellar space until it collides with something else.
Its fate is sealed - to drift until it can drift no more.
If by some miracle you have enough food and water to keep surviving, the power systems will shut down after a couple of years, rendering it physically impossible to cook or clean yourself after that.
Would survival even be worth it at this point? I don’t think so. I would open that air lock before you could say exploding head!
Not to be a spoilsport, but anyone still thinking that they might have better odds at this point has probably seen The Martian one too many times.
Just because Matt Damon survived being abandoned on Mars (to an incredible soundtrack, it has to be said) doesn’t mean you stand a chance of rescue too.
As I have explained, it’s all about science - the simple fact is, it’s nye on impossible to come to a stop without the fuel to power your thrusters.
Unless you manage to somehow bypass the laws of Physics and figure out an improvised braking system, then put in an SOS call to Cape Canaveral before you lose signal, you should probably not hold out much hope of making it home.