Life/Death/Agility 4: The Unbearable Lightness of Requirements

Another in the ongoing miniseries, Life/Death/Agility.

I've seen this argument online and heard it in conversation: the reason you can't use Agile on serious projects like the Shuttle is that there are hard requirements that can't be changed.

Apparently it's a principle of Agile that the developers can change requirements. 

I can just see a team explaining to a NASA manager, "We understand you thought you had this requirement, but you have to get over it and embrace change: because of the Agileological refactorization/cohesion principle, we're going to have to make the heat-resistant tiles out of Charmin."