System
Rocket as a system of systems
An integrated launch vehicle is 18 interdependent domains. Propulsion is where APEX started; every other domain has its own purpose, interfaces, evidence and partner capabilities.

Why an engine is only the beginning
Building an engine is the beginning.
Progressing toward a credible launch system requires coordinated development across propulsion, structures, avionics, embedded systems, software, sensors, manufacturing, quality, testing, ground systems and specialist engineering.
- Propulsion
- Structures
- Avionics
- Embedded systems
- Software
- Sensors
- Manufacturing
- Quality
- Testing
- Ground systems
- Specialist engineering
The engine is where APEX started. Each discipline above is a system of its own, with interfaces to the others.
System explorer
Select a domain
Six groups, eighteen domains. Open a group, then a domain, for its purpose, interfaces, evidence, partner capabilities and dependencies. The technical view adds the interface matrix.
Authority
Where APEX fits
Partners contribute capability. Intent, architecture, configuration and acceptance stay with APEX.
APEX Rocket Systems
Rocket System & Propulsion Program OwnerSpecialist ecosystem partners contribute capabilities. APEX retains system intent and engineering authority.
Solid amber: what APEX holds. Dashed outer ring: where partners contribute.
Engineering governance
Review gates
Each gate asks one question and needs evidence to pass. They give investors, partners and authorities a shared view of maturity.
- GateMCRMission Concept ReviewIs the mission worth doing, and is the concept feasible?
- GateSRRSystem Requirements ReviewAre the requirements complete, consistent and verifiable?
- GatePDRPreliminary Design ReviewDoes the preliminary design meet the requirements with acceptable risk?
- GateCDRCritical Design ReviewIs the detailed design mature enough to build and test?
- GateTRRTest Readiness ReviewAre hardware, procedures, facilities and people ready to test safely?
- GateFRRFlight Readiness ReviewIs the evidence sufficient to fly?
Technical view
Questions a CTO will ask
- Who owns the architecture?
- APEX.
- Who owns technical decisions?
- APEX.
- How are interfaces managed?
- Through systems engineering: interface definitions, traceability and configuration baselines under APEX authority.
- How is hardware validated?
- Progressively — material, part, component, subsystem, engine, propulsion system, vehicle — with evidence at each rung.
- How is firmware validated?
- Unit and interface tests, software- and hardware-in-the-loop, then integration — each tied to a released baseline.
- How is model confidence built?
- By predicting before each test and correlating with measurements on the same configuration.
- How are changes controlled?
- A configuration-aware digital thread links every change to the hardware, firmware, software and model revisions it affects.
- How are partners kept from becoming silos?
- Every partner is mapped to capabilities, every capability to interfaces, and every interface to evidence.
