Node A6 · Acronym decoder
HSI
Human Systems Integration
What it actually means
The discipline ensuring the human is engineered into the system, not bolted on: manpower, personnel, training, human factors, safety, habitability, and survivability considered as design domains with requirements and trades. The cheapest place to fix a usability disaster is in the requirements, and HSI is how that's supposed to happen.
Where you'll meet it
DoD systems engineering plans and design reviews, especially for crewed systems.