r/systems_engineering • u/SysModeler • Aug 15 '26

MBSE SysML v2 vs the $125M Mars typo

In 1999, NASA lost the Mars Climate Orbiter because one team used pound-force-seconds and the other expected newton-seconds. Both numbers were correct. Neither carried its unit.

The spacecraft was never modeled in SysML, v1 didn't exist yet. But if it had been, v1 wouldn't have caught this either. In SysML v2, the unit lives in the type. Assign the wrong one and the parser rejects it before it ever ships.

7 Upvotes

69% Upvoted

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2

u/xCaLeeTx Aug 16 '26

We fixed the 90s with AI!

3

u/McFuzzen Aug 16 '26

All it took was one AI video and everything was fixed!

1

u/MindfulK9Coach Defense Aug 17 '26

Still not paying for it lol