# INCOSE/ISO 15288 Life Cycle Processes

ISO/IEC/IEEE 15288 defines a comprehensive set of processes for systems throughout their life cycle. This is the backbone of modern Systems Engineering.

## Life Cycle Stages

| Stage | Purpose | Activities |
|---|---|---|
| **Concept** | Identify stakeholder needs, explore solutions | Business/mission analysis, stakeholder needs, feasibility |
| **Development** | Define and build the system | Requirements, architecture, design, implementation, integration, verification |
| **Production** | Produce/replicate the system | Manufacturing/deployment, configuration |
| **Utilization** | Use the system to achieve intended purpose | Operation in environment |
| **Support** | Sustain system capability | Maintenance, training, logistics, updates |
| **Retirement** | End of life | Disposal, data migration, decommissioning |

## Process Categories

### 1. Agreement Processes
Deal with agreements between organizations.

| Process | Purpose | Key Outputs |
|---|---|---|
| **Acquisition** | Obtain product/service from supplier | Acquisition agreement, acceptance criteria |
| **Supply** | Provide product/service to acquirer | Proposal, delivery, support agreement |

### 2. Organizational Project-Enabling Processes
Enable the organization to perform projects.

| Process | Purpose | Application |
|---|---|---|
| **Life Cycle Model Management** | Define and improve processes | Choose V-Model, Agile-SE, hybrid for project |
| **Infrastructure Management** | Provide tools, facilities, environment | Dev environments, CI/CD, labs |
| **Portfolio Management** | Prioritize projects | Resource allocation |
| **Human Resource Management** | Skills, training | Team building |
| **Quality Management** | Quality policy and assurance | Standards, reviews |
| **Knowledge Management** | Capture lessons learned | Wikis, post-mortems |

### 3. Technical Management Processes
Manage technical effort throughout project.

| Process | Purpose | When Used |
|---|---|---|
| **Project Planning** | Plan scope, schedule, resources | Start of project, continuously updated |
| **Project Assessment and Control** | Monitor progress, take corrective action | Ongoing |
| **Decision Management** | Structured decision making | Trade studies, architecture decisions |
| **Risk Management** | Identify, analyze, mitigate risks | Continuous |
| **Configuration Management** | Baselines, change control | Throughout |
| **Information Management** | Manage technical information | Throughout |
| **Measurement** | Metrics for decision making | Throughout |
| **Quality Assurance** | Process compliance | Throughout |

### 4. Technical Processes
The core engineering processes.

| Process | Purpose | Key Activities |
|---|---|---|
| **Business or Mission Analysis** | Define problem/opportunity | Identify stakeholders, analyze gaps, propose solutions |
| **Stakeholder Needs and Requirements Definition** | Elicit and refine needs | Interviews, CONOPS, stakeholder requirements |
| **System Requirements Definition** | Transform to system requirements | Requirements analysis, allocation, traceability |
| **Architecture Definition** | Define system architecture | Functional/physical architecture, views |
| **Design Definition** | Detailed design of system elements | Interfaces, components, data structures |
| **System Analysis** | Support analysis-based decisions | Trade studies, modeling, simulation |
| **Implementation** | Realize system elements | Code, configure, build |
| **Integration** | Assemble into complete system | Integration testing, interface verification |
| **Verification** | Confirm conformance to requirements | Tests, reviews, analysis |
| **Transition** | Move to operational environment | Deployment, training, data migration |
| **Validation** | Confirm meets stakeholder needs | Acceptance testing, user validation |
| **Operation** | Use system | Monitoring, support |
| **Maintenance** | Sustain and improve | Bug fixes, updates, enhancements |
| **Disposal** | Retire system | Decommission, archive, secure deletion |

## Tailoring 15288 for Software/AI Projects

15288 is process-agnostic - you tailor it. For modern software/AI:

| Process | Tailoring Approach |
|---|---|
| **Business/Mission Analysis** | Use product discovery, user research |
| **Requirements** | Lightweight but still capture needs; user stories + acceptance criteria |
| **Architecture** | ADRs, diagrams, evolve iteratively |
| **Design** | API contracts, schemas, agent designs |
| **Implementation** | Agile/sprints, CI/CD |
| **Integration/Verification** | Automated tests, eval suites |
| **Transition/Validation** | Canary releases, feature flags, A/B testing |
| **Operation/Maintenance** | Observability, on-call, continuous improvement |
| **Risk/Config Management** | Git, feature flags, risk registers |
| **Decision Management** | ADRs serve as decision records |

## Practical Application to AI Systems

| 15288 Process | AI System Application |
|---|---|
| **Stakeholder Needs** | "Reduce support costs", "Automate research", etc. |
| **System Requirements** | Accuracy, latency, cost, safety, eval thresholds |
| **Architecture Definition** | Agent architecture, tools, memory, RAG, routing |
| **Verification** | Unit tests, schema validation, guardrail tests |
| **Validation** | Eval sets, human eval, red teaming, user acceptance |
| **Operation** | Observability, evals in prod, cost monitoring |
| **Maintenance** | Prompt updates, model updates, eval regression |

## Quick Reference Checklist

For a new project, ensure coverage of:
- [ ] **Needs captured** - Stakeholder needs documented
- [ ] **Requirements defined** - System requirements with traceability
- [ ] **Architecture decided** - Documented with trade studies
- [ ] **Interfaces managed** - ICDs/contracts defined
- [ ] **Risks tracked** - Risk register maintained
- [ ] **V&V planned** - Test/eval plan exists
- [ ] **Decisions recorded** - ADRs for key decisions
- [ ] **Config managed** - Version control in place
- [ ] **Observability planned** - Monitoring from day one
- [ ] **Lifecycle considered** - Ops, maintenance, eventual retirement

## Related Notes

- [[Lifecycle/V-Model-Application.md]] — V-Model details
- [[Foundations/Systems-Engineering-History-Standards.md]] — Standards context
- [[Trade-Studies/Trade-Study-Methodology.md]] — Decision management
- [[Verification-Validation/V-Model-And-VV-Planning.md]] — V&V
- [[../AgenticEngineering/Production/Deployment-Architecture.md]] — Deployment

## Sources

* ISO/IEC/IEEE 15288:2015  
* INCOSE Systems Engineering Handbook v5  
* NASA Systems Engineering Handbook  
* MITRE Systems Engineering Guide