Requirement specification document
Pick the format you are held to. Each one runs the same workflow against the same model, and only the document shape changes.
Other tools hand you empty templates to type into. Because the document chain maps to requirement levels in the model — stakeholder needs at the top, system requirements below, satisfied by parts — one Dalus model emits the whole chain and cross-document traceability comes free.
ISO/IEC/IEEE 29148
3 documentsSystem Requirements Specification (SyRS)
The default, and the document most teams mean when they say requirement spec: requirements, verification methods, interfaces and traceability, which is where the model has the most to give.
Operational Concept Document (OpsCon / CONOPS)
Generates from the model directly: use cases, actors and states are its raw material. Ships as a formal programme deliverable where operational concept and use cases are called out separately.
Software Requirements Specification (SRS)
For software-heavy scope, completing the 29148 family.
MIL-STD-961E DID
1 documentECSS-E-ST-10-06C
2 documentsTechnical Requirements Specification (TS)
The European space standard, for missions run to ECSS. Also freely available to load.
System Requirements Document (SRD)
The same DRD under the name most ESA projects actually use, applied at system level: the Level-1 requirements for the system as a whole, derived from the Level-0 end-user requirements above it.