And that's not really the most important lesson to learn from the Challenger disaster!
The Challenger disaster wasn't a single mistake or flaw or random chance that resulted in the death of 7 people and the loss of a 2 billion dollar spaceship.
But we always want to optimize. We want to do things cheaper, quicker, more at once.
So going 110% as fast as the spec says? probably OK
You've been going 110% all the time. It's worked out just fine. You're doing great, no problems.
You start to think of 110% as the new normal, and you think of it as just 100%.
The computer tests all those except "never write it down". Guess which one gets violated?
But this kind of thing doesn't just happen to some punks in an office doing spreadsheets. It happens to actual rocket scientists.
You've normalized going outside the stated rules, and nothing went wrong. So why not go a little more? After all, 110% was just fine...
Steve wrote down his password and it's not like he got fired for doing that. So why not do it too?
You don't get any "HEY STOP WRITING DOWN YOUR PASSWORDS" feedback until the whole company gets hacked and your division is laid off.
Like, I like to joke that my roommate's cat is very smart. We want to keep her off the kitchen counter for sanitary reasons, so whenever we see her on the counter, we spray her with water.
... when there's someone there to see you.
So people learn.
They put their passwords in their wallet and in their phone.
The O-rings on the solid rocket boosters had a problem where hot gases would leak past them during lift-off, but every time this happened, the O-ring would shift and reseal the leak.
But other things were pushed.
If you had to launch at colder or hotter, you might need different materials and more expensive tests. So you decide on limits.
They don't self-seal if they're too hard and brittle from the cold. The gases keep leaking. The hole widens.
It happens at the time when the rocket is undergoing the strongest stresses from take-off, and the tank fails.
the crew probably survived in the reinforced cabin until it struck the ocean
And the road opens and it works perfectly at 50MPH.
The police stop a few of them.
But as people go on the road and get used to it, they start going 60 MPH, just cause they can and nothing bad seems to happen. The normal becomes 60 MPH
And it's fine, for a while.
And a bunch of people crash.
It's that you have to consider normalization of deviance when designing systems:
How will these rules interact with how people naturally bend the rules?
Cause 17 years after the Space Shuttle Challenger disintegrated on liftoff, the Space Shuttle Columbia broke up on re-entry.
It had to be covered in insulation to prevent ice from forming on it, and damaging the tank.
And this didn't cause a problem, the first 112 times they launched.
And it turns out that even relatively lightweight foam can make a big hole when it hits the wing while the orbiter is moving at Mach 2.46
But they'd gotten lucky 112 times in a row. So they didn't consider it a priority.
Your system not breaking doesn't mean it works and is a solid design.
It might just mean you've gotten lucky, a lot, in a row.
at a previous job we had some tests that ran on machines, and they had a step where they'd install some special tools to run the test with, then use them.
it turned out the "did we install the tools right?" part was always skipped.
So we'd get the expected success or the expected failure. Seems to work fine, right?
And that affected these tools, too.
But then someone accidentally broke the tools with a bad commit... and we didn't notice for weeks.
Which'd be fine and would have triggered failures, except we had that long-standing bug (that we didn't know about) where failing an install would still continue to run the test.
But now that we were keeping old files around, it meant the test would still run, as it'd use the files still on the box from the last time it'd worked.
We were wrong. Nothing was working. But we were lucky, so it looked like it did.
So no one noticed when another 5 lines of errors popped up in a 2000-line log file
Because they didn't hit all the failures at once. They rolled the same dice and didn't come up all 1s.
But sometimes the dice come up the wrong way and all of them happen at once.
You especially don't realize it when it's someone else hitting that limit!
You found a gem and a rusty sword and a health potion, but now you found a key and you don't have room in your backpack.
You definitely need the key, but that doesn't mean you have to break down and fail the mission.
Because you'll have a lot better success in getting things done once you have some capacity to deal with things.
But with disability you might be spending one every day just one the disability
Depression is one. Anxiety, PTSD, ADHD, OCD... there's plenty of illnesses that can use up spoons.
If you try to load 9 boxes in your car and only 7 will fit, you don't get mad at the car for not "roughing it out"
Keep that in mind.