System lifecycle

The system lifecycle is the course of developmental changes through which a system passes from its conception to the termination of its use and subsequent salvage.

For example, a system lifecycle might include the phases and activities associated with the analysis, acquisition, design, development, test, integration, operation, maintenance, and modification of the system.

System engineering

In systems engineering, the system lifecycle is an examination of a system or proposed system that addresses all phases of its existence to include system design and development, production and/or construction, distribution, operation, maintenance and support, retirement, phase-out and disposal.

Conceptual Design

The Conceptual Design stage is where an identified need is examined, requirements for potential solutions are defined, potential solutions are evaluated and a System Specification is developed. The System Specification represents the 'technical requirements' that will provide overall guidance for system design. Because this document governs all future development, the stage cannot be completed until a Conceptual Design Review has determined that the System Specification properly addresses the motivating need.

Key steps within the Conceptual Design stage include:

Need Identification

Feasibility Analysis

System Requirements Analysis

System Specification

Conceptual Design Review

Preliminary System Design

During this stage of the system lifecycle, subsystems that perform the desired system functions are designed and specified in compliance with the system specification. A Development Specification is produced that is sufficient to perform detailed design and development.

Key steps within the Preliminary Design stage include

Functional Analysis

Requirements Allocation

Detailed Trade-Off Studies

Synthesis of System Options

Preliminary Design of Enginering Models

Development Specification'

Preliminary Design Review