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Comment by fosap | Hacker News Reader

I'm almost 100% sure engineers use the SI system. (unlike physicist that use a system that seems to be fitting). And the SI system says that 100.000 and 100,000 are the same. The Si system only uses space to group numbers like 12 343,123 12 for twelf thousand and so on.

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My thought was that anything that used the decimal comma could be confusing when dealing with vectors.

However, I wouldn't go so far as to say they use SI across the board. I know aerospace engineering in the US can often switch between imperial and metric depending on which contractors work on the project (this resulted in a mission failure on at least one occassion: http://en.wikipedia.org/wiki/Mars_Climate_Orbiter) and it could be the same for other fields.

You'd be right. At NASA we could use whatever we wanted. There was no directive to do one thing or another (at least not one I ever knew about) - only the conventions that allowed you could communicate with your peers. Much of the technology we used had evolved over decades. Changing it to metric would have been insane.

An interesting line from that wikipedia article: This error has since been known as the "metric mixup" and has been carefully avoided in all missions since by NASA.

This is categorically not true, as I worked before and after that, and it had zero impact on the units we used or how we checked them. Most of the time nothing was metric, so it didn't matter.

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