This paper describes a Zero Trust Architecture (ZTA) approach for the survivability development of mission critical embedded systems. Designers could use ZTA as a systems analysis tool to explore the design space. The ZTA concept of “never trust, always verify” is being leveraged in the design process to guide the selection of security and resilience features for the codesign of functionality, performance, and survivability. The design example of a small drone for survivability is described along with the explanation of the ZTA approach.