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The Challenger Disaster
What went wrong!?
Challenger was the name of 
one of NASA’s space shuttle.
The purpose of the shuttle was to make 
multiple trips and launch satellites into space.
Challenger was one of NASA's greatest triumphs.
It was the second shuttle to reach space,
in April 1983.
Also, It successfully completed 
nine milestone missions.
But Challenger was also 
one of NASA's greatest tragedy.
On its 10th launch, on Jan. 28, 1986,
shuttle was torn apart,
its parts blew into flames
and fell off into water,
killing all of its crew members.
And all this happened just 73 seconds after its flight.
The accident changed the space program forever.
In this video we will see - 
what was the reason behind this accident.
But before that - 
lets see what exactly happened?
Challenger was on its 10th mission in space,
with the aim of deploying 
Tracking and Data Relay Satellites
and observe Halley’s comet.
Challenger was at the time the 
most-flown orbiter in NASA’s fleet,
setting numerous records.
The mission experienced trouble at the outset, 
as the launch was postponed for several days.
On the night before the final launch day,
central Florida was swept by a severe cold wave
that deposited thick ice on the launch pad.
some engineers warned higher officials 
regarding this and that this might be a problem,
but the warning went unheeded.
All appeared to be normal on the morning of launch,
when thousands of people 
on the ground,
including the families of astronauts
witnessed an explosion just 73 seconds after liftoff,
at an altitude of 14,000 metres (46,000 feet).
Millions more watched the wrenching 
tragedy unfold on live television.
But, why did this explosion happend?
Let us understand basic composition of any space shuttle
any Space Shuttle consists of three major components:
First, the Orbiter which houses the crew;
then we have, External Tank
that holds fuel for the main engines;
and two Solid Rocket Boosters
which provide most of the Shuttle's lift 
during the first two minutes of flight.
This happened because the space 
shuttle's external fuel tank collapsed,
releasing all its liquid hydrogen and liquid oxygen propellants.
As the chemicals mixed,
they ignited to create a giant fireball 
thousands of feet in the air.
Note at this point the shuttle itself was intact
and all crew members were safe and sound.
But due to the explosion in fuel tank,
the shuttle became unstable and 
was trying very hard to stay on its path,
and finally the tank broke off the shuttle.
The tail and the main engine section broke off.
Big chunks of the shuttle fell out of the sky, 
and they further broke up when they hit the water
with enough force to crush everything inside the cabin.
Debris rained into the Atlantic Ocean 
for more than an hour after the explosion;
searches revealed no sign of the crew.
The tragedy and its aftermath 
received extensive media coverage
which prompted NASA to suspend 
all its space missions immidiately.
And the question that now 
NASA had to answer was
what went wrong?
Shortly after the disaster,
President Ronald Reagan appointed a special commission
to see what actually went 
wrong with the Challenger.
This commission was headed by
former secretary of state William Rogers,
the commission included former astronaut Neil 
Armstrong and famous scientist - Richard Feynman.
Their investigation revealed that
It was a cold morning on 
the day of Challenger’s launch
Temperature was much below freezing point.
And some parts making the shuttle
specially the O-rings can not function properly.
To make things worse -
NASA had no prior experience of launching a shuttle
at a such cold temperature.
The O-rings used in Challenger's Rocket Boosters,
their main function was
to seal the joints so tightly
they would prevent violently hot gases 
from escaping as spears of flame.
O-rings become brittle in the cold temperature, 
and failed at doing its function.
Because of this gases got mixed, fire started
causing the spacecraft to explode and disintegrate.
Let us see this in more depth now,
In the booster rocket skin, there were 
grooves where structures called O-rings,
made of rubber,
were supposed to fit in.
And their fuction was to seal the joints.
Note that two O-rings were used in Challenger,
primary and secondary
Just in case first o-ring couldn’t do its work,
the second would be sufficient.
Please understand what was the fuction of O-ring here,
the O-rings do not initially seal the structure
their purpose is to start the work 
when initial gas leak is observed
When the initial bit of gas hits the first primary O-ring,
that pressure and temperature expands the o-ring
making the seal.
So now, as you would understand
 
 
 
And this is where the low temperature thing comes in.
At lower temperature, the o-rings lose flexibility
failing to expand and prevent the leak.
Scientist Richard Feynman, demonstrated the O-ring 
flaw to the public using a simple glass of ice water.
The O-rings were never tested 
in extreme cold in the first place.
Some Thiokol and NASA engineers did raise the problem 
on the morning of the launch, which went unheard.
Some higher officials of Thikol and NASA both knew 
the problem but they still failed to take any action.
As Richard Feynman concluded 
at the final meeting of this commission
thet Challenger was man-made disaster
which didn't have to happen.
The thinking of NASA’s and Thiokol’s officers that
“nothing has happened, so nothing will happen”
took the lives of 7 crew members.
But along came many learnings as well
NASA grounded its shuttles until 1988.
The problem with o-rings was fixed.
an additional heating pad was fit into the system,
to make sure that they remain warm enough to 
function properly, no matter how cold it gets outside.
NAS also changed many policies and management strucutre,
to ensure that a warning against 
a launch will newer again go unheard.
So it all comes down to materials, their properties 
at different temperature, pressure and other conditions.
 
If you are interested in all of this,
and if you want to study more about his,
you should download our app today
and watch videos for Mechanical properties of solids.
to understand all of this better.
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Travelling to space is one of the hardest and 
dangerous things humans have ever done
and space companies have been trying to do it right.
But the hard truth is
that we can learn and minimize risk
but we may not ever be able to do without it.
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