[AKN #21] Why did the Challenger explode on national television and THE ultimate horse girl
another krappy newsletter #21
Sup homies?
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Just like your tryhard colleague who shamelessly plays the corporate grift, I respond to all emails. I am your tryhard.
This is the part of the newsletter where I tell you where I am sending it from. Mostly I send it from the same place every week due to the quarantine, but today I have the joy of writing to you from my parents’ home in New York.
I feel obligated to explain myself for traveling during this time period.
I was very careful. I reduced my exposure to other people two weeks before getting on the plane, I got tested 72 hours before getting on the plane, I am getting tested a few days after being off the plane, I picked a flight during a downtime in the airport, I wore my tight-fitting mask for the entire flight, I picked an airline that guaranteed no one sitting next to me throughout the flight…you get the point. Overall, I have high confidence that I was not infected before, during, or after the flight.
BUT, still, with all of those precautions, there are a lot of people who would lecture me about how I am not being responsible. They believe you should not be traveling. Period. No matter how thoughtful you were. No matter how much you mitigated risk. You will be lampooned by this perpetually outraged group that wears not seeing their family during COVID like a weird badge of pride.
Look. You are better than me. Congrats. I hope you enjoy the praise your fake Internet friends bestow upon the rage porn you spew from your mentally unstable fingertips.
That last paragraph might be how I sign off my Christmas card next year.
On to the newsletter!
Table of contents
What is full of krapp?
The explosion of the Challenger
THE Horse girl
1. What is full of krapp?
For newbies who may not remember signing up for this and for long time readers who struggle to describe what goes on here, I think now is a good time to reflect on what this newsletter even is. Good for me to reflect on it too. Cause I am not really sure I get it either…
What is this?
It is a newsletter about nothing. The only common thread between the topics discussed is that I wrote them. No other “theme”. But they are mostly long form comedy posts describing my feelings and/or a deep dive on a complicated or taboo subject. The ideal post brings a smile to your face, but also teaches you something in the process. Just like an episode of Gilmore Girls.
Here are some examples:
When do you send it?
I send out an email every Tuesday in this format.
In the future, I will publish solo essays as well. Which I am hearing would be easier for you all to share than these meaty ass newsletters I seem to love so much.
Why do you write this?
I have three goals with this newsletter:
Increase laughter. The world is too serious. Have you read the news recently? Man. That show sucks. I cannot believe it keeps getting renewed for another season. I think you can be informed without constantly being sad.
Decrease entropy. The world tends toward disorder. The deluge of information being created at all times leaves us more confused than we started. There is a lot of value in sucking up all of the information out there and condensing it into a coherent message. Bringing order to the disorder.
Increase exposure to interesting people. I have met some very cool people during this whole journey. One of the benefits of writing this has been finding more people who are interested in the stuff I am into. As the show goes on, I hope to keep finding more of those people.
A holiday thanks for all of you reading
Thanks to all of you for reading this week over week. I enjoy writing it and I love to hear that some of you love reading it. I hope you enjoy your holiday season. Whatever you choose to celebrate and wherever you choose to do it.
See how I didn’t fall into the Merry Christmas trap? Pretty impressive, I know. I went to Berkeley so I can do the agnostic, politically correct sign off in my sleep.
Looking forward to another year together with you <3
2. The explosion of the Challenger
On January 28, 1986, the Space Shuttle Challenger (OV-099) broke apart 73 seconds into its flight, killing all seven crew members aboard. All on national television…
I have a morbid fascination with why things break. In fact that’s what I do for a living. So naturally, I found myself down a serious rabbit hole on this one.
Allow me to teach you what I learned about it.
The loss of the Challenger originated with a system failure of one of its solid rocket boosters.
What is a solid rocket booster (SRB)?
You need a lot of force to leave Earth’s gravitational field. The twin solid rocket boosters on the Space Shuttle were responsible for producing enough force (also called thrust) to escape the gravitational pull and get into orbit.
These things are VERY expensive. So instead of letting them blow up or disintegrate in the atmosphere, they were designed to remove themselves from the Space Shuttle once they were no longer needed for ascent and parachute into the Atlantic Ocean where they were recovered, examined, refurbished, and reused.
Pretty cool, right? Wrong. It is really cool. We are talking about space! It is dope!
Until it explodes at which point it is decidedly not cool…
So what was the reason this SRB blew up?
The 5 Whys approach to failure analysis
When we begin a failure investigation, we like to channel our inner 5-year-old and ask why ad nauseum until we can’t ask why anymore. The idea is that you are drilling down into the exact reason that explains what you saw.
For the failure of the SRB, this would look something like this:
Why did the Challenger break apart 73 seconds into its flight?
Aerodynamic forces broke up the orbiter.
Why was it susceptible to aerodynamic forces?…Isn’t it a rocket?
Prior to it breaking apart, there was a separation of the right-hand SRB's aft field joint attachment and the external tank exploded (resulting in a a structural failure). This structural breakdown compromised its ability to survive the aerodynamic forces from the launch.
Well…why did that happen?
An O-ring seal failed on liftoff that caused a breach in the SRB joint. Without the seal, pressurized burning gas from within the solid rocket motor was now able to reach the external fuel tank.
And in what may be the least surprising thing you read in this: when you add a burning fire into an ungodly large fuel tank, you will often times get an explosion…
What is an O-ring?
O-rings are used to prevent leaks by creating a seal between two parts.
Specifically, in the Challenger, the function of this O-ring was to dynamically seal off the exit route for the burning gas to reach the outside.
When it is working properly, upon launch the pressure from the gas exerts pressure on the O-ring and that O-ring seals the gap.
But why did the O-ring fail?
O-ring seals used in the joint were not designed to handle the unusually cold conditions that existed at this launch.
Why was the O-ring susceptible to failure in cold conditions?
When an O-ring is cooled below its Tg (glass transition temperature), it loses its elasticity and becomes brittle. The cold O-ring, once compressed, will take longer than normal to return to its original shape.
A diagram of the O-rings and how they operate at the two different temperatures:
So because it was cold before the launch, the O-ring was not as flexible as it needed to be at the time of launch. Thus, it did not move as quickly as it needed upon launch in order to block the burning gas from making its way to the external fuel tank.
Meaning: If we launched the Challenger above the glass transition temperature, this shuttle would not have had this failure occur. Literally all they had to do to prevent this tragedy was delay the flight for warmer temperatures.
Some additional fun facts:
Morton Thiokol (the maker of the SRB) had been so concerned about the O-rings that they recommended NASA not launch the shuttle in temperatures below 53 degrees. They just didn't have enough data to determine if the O-rings would seal properly at lower temperatures. Unfortunately, they pushed forward and got one more data point…
The redesign of the SRB incorporated three O-rings instead of two, with the joints themselves having onboard heaters that can be turned on when temperatures drop below 50 °F (10 °C). No O-ring issues have occurred since Challenger.
Richard Feynman was a member of the commission that investigated the cause of the explosion. He played an integral role in TV history when he demonstrated the O-ring issue by placing a small O-ring into ice-cold water and subsequently showed its loss of flexibility.
Sources for you to geek out further on this if you are into that kind of thing:
I highly recommend the Netflix documentary on the Challenger.
Material science explanation of the O-ring property change that occurs in the polymer chains at the glass transition temperature
3. THE Horse girl
I need you to know that there exists a woman in Norway who taught herself how to run and jump like a horse.
The human spirit is amazing.
Closing time
As always, reply to this email and say what’s up. Promise to hit you back with an artisanal, hand-crafted response.
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