An Operational Requirements Document (ORD) was replaced by the Capability Development Document (CDD). The ORD described the overall requirements for one system, how it interacts with other systems, and a systems performance goals. An ORD is generally more detailed than a Concept of Operations (CONOPS). Older programs will have an ORD.
The Mission Needs Statement (MNS) was replaced by the Initial Capabilities Document (ICD).
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