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My $500M Mars rover mistake

chrislewicki.com

151–160 of 361 posts

Re: My $500M Mars rover mistake

#151
In my company people aren’t allowed to change org level GitHub settings without a second person watching over them, but NASA let a 28 year old kid run electricity into spacecraft without oversight?

Really seems like anything which when done improperly could cause millions of dollars in damage, there should be a second person reviewing your setup first.

Re: My $500M Mars rover mistake

#152
post #151

In my company people aren’t allowed to change org level GitHub settings without a second person watching over them, but NASA let a 28 year old kid run electricity into spacecraft without oversight? Really seems like anything which when done improperly could cause millions of dollars in damage, there should be a second person reviewing your setup first.

The average age of engineers running Apollo 11 was supposedly 28

https://www.popularmechanics.com/space/a4288/4318625/?utm_so...

Re: My $500M Mars rover mistake

#153

I am a Mechanical/Aerospace engineer.... I wish my scariest stories 'only' involved a potential bricking of a main computer on an unmanned $500M rover. No... I was the senior safety-crit signoff on things carrying human lives. I had to look over pictures of parts broken from a crash and have the potential feeling of 'what-if that's my calculation gone wrong'. My joint that slipped. My inappropriate test procedure inv…

That reminds me of a fiction-quote by one of my favorite authors, where a welding-instructor has just finished sharing a (somewhat literal) post-mortem anecdote of falsified safety inspections.

> He gathered his breath. “This is the most important thing I will ever say to you. The human mind is the ultimate testing device. You can take all the notes you want on the technical data, anything you forget you can look up again, but this must be engraved on your hearts in letters of fire.

> “There is nothing, nothing, nothing more important to me in the men and women I train than their absolute personal integrity. Whether you function as welders or inspectors, the laws of physics are implacable lie-detectors. You may fool men. You will never fool the metal. That’s all.”

> He let his breath out, and regained his good humor, looking around. The quaddie students were taking it with proper seriousness, good, no class cut-ups making sick jokes in the back row. In fact, they were looking rather shocked, staring at him with terrified awe.

-- Falling Free by Lois McMaster Bujold

Re: My $500M Mars rover mistake

#154
post #146

I am a Mechanical/Aerospace engineer.... I wish my scariest stories 'only' involved a potential bricking of a main computer on an unmanned $500M rover. No... I was the senior safety-crit signoff on things carrying human lives. I had to look over pictures of parts broken from a crash and have the potential feeling of 'what-if that's my calculation gone wrong'. My joint that slipped. My inappropriate test procedure inv…

And the engineers designing safety mechanisms for nuclear weapons probably think you have it easy.

[flagged]

Re: My $500M Mars rover mistake

#155
post #38

Ohhhh I hate things that you “just have to not screw up.” A fiddly manual process with so many possible ways to screw something up is almost guaranteed to see a catastrophic failure. If this really manual fiddly process was really the only way they could test the motors, I’d say that’s a big failure on the design engineer’s part.

Test requirements often arise after system design is complete. Engineers need time to examine the system, theorize failure modes, and design the tests. Also time to test the system, find some unexpected failure mode, and then design yet more tests.

Would it be so hard to add a diagnostic interface? That’s all we’re talking about here. It seems like you’re making the problem more difficult than it is. And they’d had to have known ahead of time if they wanted to test voltage curves of motors.

Your answer is good in the general case, but for the anecdote, the design was clearly bad.

Re: My $500M Mars rover mistake

#157

Really well written story. As a software engineer, I have a couple stories like this from earlier in my career that still haunt me to this very day. Here’s a short version of one of them: Like 10 years ago, I was doing consulting work for a client. We worked together for months to build a new version of their web service. On launch day, I was asked to do the deployment. The development and deployment process they had…

Around 15 years ago, I was packing up getting ready to leave for a long weekend. One of our marketing people I was friends with comes over with a quick change to a customers site.

I had access to the production database, something I absolutely should not have had but we were a tiny ~15 person company with way more clients than we reasonably should have. Corners were cut.

I write a quick little UPDATE query to update some marketing text on a product and when the query takes more than an instant I knew I had screwed up. Reading my query, I quickly realize I had ran the UPDATE entirely unbounded and changed the description of thousands and thousands of products.

Our database admin with access to the database backups had gone home hours earlier as he worked in a different timezone. It took me many phone calls and well over an hour to get ahold of him and get the descriptions restored.

The quick change on my way out the door ended up taking me multiple hours to resolve. My friend in marketing apologized profusely but it was my mistake, not theirs.

As far as I remember we never heard anything from the client about it, I put that entirely down to it being 5pm on Friday of a holiday weekend.

Re: My $500M Mars rover mistake

#158

I am a Mechanical/Aerospace engineer.... I wish my scariest stories 'only' involved a potential bricking of a main computer on an unmanned $500M rover. No... I was the senior safety-crit signoff on things carrying human lives. I had to look over pictures of parts broken from a crash and have the potential feeling of 'what-if that's my calculation gone wrong'. My joint that slipped. My inappropriate test procedure inv…

> I had to look over pictures of parts broken from a crash and have the potential feeling of 'what-if that's my calculation gone wrong'.

Does it inevitably come down to that for someone? I mean even if its a detail that a procedure couldn’t have caught, someone is responsible for forming good procedures. I suppose there could be several factors. But it seems like ultimately someone is going to be pretty directly responsible.

Just interesting to think about in the context of software engineering and kinda even society at large where an individual’s mistakes tend to get attributed to the group.

Re: My $500M Mars rover mistake

#159
post #146

I am a Mechanical/Aerospace engineer.... I wish my scariest stories 'only' involved a potential bricking of a main computer on an unmanned $500M rover. No... I was the senior safety-crit signoff on things carrying human lives. I had to look over pictures of parts broken from a crash and have the potential feeling of 'what-if that's my calculation gone wrong'. My joint that slipped. My inappropriate test procedure inv…

And the engineers designing safety mechanisms for nuclear weapons probably think you have it easy.

Yep, that's fair!

But my understanding is the default behaviour of most nuclear weapons (other than Hiroshima-style ones) is "blows itself to pieces without detonating the nuclear part", rather than "vapourises everyone within a mile".

Everything needs to go right for a nuclear weapon to actually blow up with a significant yield.

Re: My $500M Mars rover mistake

#160

Really well written story. As a software engineer, I have a couple stories like this from earlier in my career that still haunt me to this very day. Here’s a short version of one of them: Like 10 years ago, I was doing consulting work for a client. We worked together for months to build a new version of their web service. On launch day, I was asked to do the deployment. The development and deployment process they had…

At a place I was consulting about 10 years ago one of the internal guys on another product dropped the prod database because he was logged into his dev db and the prod db at the same time in different windows and he dropped the wrong one. Then when they went to restore the backups hadn't succeeded in months (they had hired consultants to help them with the new product for good reason).

Luckily the customer sites each had a local db that synced to the central db (so the product could run with patchy connectivity), but the guy spent 3 or 4 days working looooong days rebuilding the master db from a combination of old backups and the client-site data.

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