This is the space shuttle lifting off on what was about to become one of its most dangerous Journeys into space.
Almost immediately fuel started leaking out of its right engine
and just 5 seconds later an electrical supply failed
knocking its engine control computers offline.
Unaware of what was really going on beneath them
the space shuttle crew spent the next 8 minutes just moments away from a catastrophic failure
when suddenly they ran out of liquid oxygen.
The shuttle had experienced two major problems that should have ended the mission
but miraculously, they happened in such a way
that actually ended up saving the crew from complete disaster.
We modeled the entire thing to show you the tiny objects that led to these huge problems
and how sheer luck and miraculous circumstances
ended up saving the space shuttle.
In order to understand why this flight was so dangerous in the first place
we need to look inside the shuttle's payload bay.
It was carrying the Chandra Observatory Telescope
which was the largest and heaviest thing shuttle ever launched.
This combination put the mission over the shuttle's weight limit.
It had to shave off several tons before the flight
and so the crew was limited to five people
a lighter external tank was used
and all three main engines were swapped out for lighter ones.
One of these was engine 2019
which had already flown on 18 missions
making it one of the most used space shuttle engines.
Over time cracks had started to show in a couple of its liquid oxygen posts
These are the thin pipes that carry liquid oxygen into the combustion chamber.
If one of these failed mid-flight it would rip the engine apart and destroy the entire vehicle.
Instead of replacing these NASA simply deactivated them
by placing a small metal pin at the top which stopped the liquid oxygen from flowing through.
This was common practice for NASA and it saved the engine from going through a lengthy refurbishment
but as space shuttle Columbia ignited its engines, one of these metal pins worked its way loose
and shot itself into the combustion chamber at over 30 m/ second.
In the blink of an eye it bounced off the chamber walls
and punctured a hole in the delicate engine nozzle.
This part of the engine is made up of over 1,000 thin tubes
which circulate the ultra-cold liquid hydrogen to stop the nozzle from melting.
From here the hydrogen makes its way into the combustion chamber
where it ignites and produces thrust.
When the pin collided with the nozzle it ripped a hole in three of the pipes
and liquid hydrogen began pouring out of the engine.
If just two more of these pipes had been damaged the nozzle would have melted
causing a chain reaction that would have completely destroyed the vehicle.
The space shuttle was just barely hanging on but all of this went completely unnoticed
since none of the sensors could detect the leak.
What the sensors did detect was a lower chamber pressure
since less hydrogen was making its way into the combustion chamber.
In order to fix this
the onboard computers automatically started pumping more liquid oxygen into the engine
which brought the pressure back up to the correct amount.
This meant that the shuttle was now burning through its liquid oxygen too quickly
and if it continued like this it would run out way before reaching orbit.
But while all this was going on a completely unrelated electrical problem had occurred in the vehicle
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Space Shuttle Columbia had just left the launch pad and was already on the verge of a complete disaster.
Its right engine was burning through too much liquid oxygen and if it ran out
the shuttle might not have made it into orbit or even worse, the engines could have ripped themselves apart.
Amazingly a completely separate problem was about to save the day.
Inside the payload bay were a series of electrical wires that carried power to instruments all over the vehicle.
One of these wires ran alongside a small screw that had been overtightened and had a very sharp edge.
Over the course of many flights, this wire had rubbed against the screw
and its insulation had been slowly worn away.
5 seconds into the flight the exposed wire arced onto the screw
causing a short circuit and setting a number of instruments offline.
This immediately set off all kinds of warnings inside the cockpit
one of which was a fuel cell warning.
The fuel cells aboard shuttle used hydrogen and oxygen to produce all of the electricity for the vehicle.
If one of these went wrong the results would be catastrophic.
Luckily this was just a faulty reading and there was nothing wrong with the fuel cells.
The real problem was lurking down below.
Two computers in charge of controlling the shuttle's engines had been knocked offline
thanks to the electricity shortage.
Each engine had a main computer and a backup computer which would take over if something went wrong.
The right engine, which was leaking fuel had just lost its backup computer
and the center engine lost its main computer.
This caused a unique problem that actually turned into a solution.
You see, under normal circumstances both computers run simultaneously.
The data from both computers is compared and averaged out and this is what is used to control the engines.
This means that if a sensor on one of the computers is reading abnormally high or low
it won't have such a big effect on the engine.
As it turned out, the pressure sensor on the backup computer was reading incorrectly
and it was sending back an abnormally high pressure reading.
Since the main computer wasn't there to cancel this out
it tricked the engine into thinking the pressure was too high.
Because of this the engine started pumping less liquid oxygen into the engine to reduce the pressure.
This now meant that although the right engine was guzzling through too much oxygen
the center engine was using less than normal
and so the problems canceled each other out.
If the center engine didn't have a faulty sensor or if the electrical supply hadn't failed
the whole shuttle would have run out of liquid oxygen much sooner
and it wouldn't have reached orbit.
Had this actually happened, the crew would have had to make an aborted landing back on Earth
still carrying the enormous telescope on their backs.
By sheer coincidence, two completely separate problems occurred that perfectly canceled each other out
allowing shuttle to reach orbit just 5 m/ second off its desired speed.
In the end, the shuttle was able to make up for this by using its OMS engines
and the Chandra Telescope was successfully deployed.
Since its main engines weren't needed for the rest of the mission, the shuttle and its crew safely made it
back to Earth without any issues.
Now time for the Primal Space giveaway.
The winner of the previous giveaway is Eric. Congrats!
In the next video, we'll be giving away this custom Primal Space design Shuttle poster available in our store.
All you need to do is sign up at the link below
like the video, and leave a comment saying what you think about the Space Shuttle.
Thank you very much for watching and I'll see you in the next video.