                   2.0 Fundamentals of Systems Engineering




                                                      TABLE 2.2-1 Project Life Cycle Phases
 Phase                                 Purpose                                                          Typical Outcomes
                     Pre-Phase A       To produce a broad spectrum of ideas and alternatives            Feasible system concepts




 Pre-Formulation
                     Concept           for missions from which new programs/projects can be             in the form of simulations,
                     Studies           selected. Determine feasibility of desired system, develop       analysis, study reports,
                                       mission concepts, draft system-level requirements, assess        models, and mock-ups
                                       performance, cost, and schedule feasibility; identify
                                       potential technology needs, and scope.


                     Phase A           To determine the feasibility and desirability of a suggested     System concept definition
                     Concept and       new system and establish an initial baseline compatibility       in the form of simulations,
                     Technology        with NASA’s strategic plans. Develop final mission concept,      analysis, engineering models
                     Development       system-level requirements, needed system technology              and mock-ups, and trade



 Formulation
                                       developments, and program/project technical management           study definition
                                       plans.

                     Phase B           To define the project in enough detail to establish an initial   End products in the form of
                     Preliminary       baseline capable of meeting mission needs. Develop               mock-ups, trade study results,
                     Design and        system structure end product (and enabling product)              specification and interface
                     Technology        requirements and generate a preliminary design for each          documents, and prototypes
                     Completion        system structure end product.

                     Phase C           To complete the detailed design of the system (and its           End product detailed designs,
                     Final Design      associated subsystems, including its operations systems),        end product component
                     and Fabrication   fabricate hardware, and code software. Generate final            fabrication, and software
                                       designs for each system structure end product.                   development

                     Phase D           To assemble and integrate the system (hardware, software,        Operations-ready system




 Implementation
                     System            and humans), meanwhile developing confidence that it             end product with supporting
                     Assembly,         is able to meet the system requirements. Launch and              related enabling products
                     Integration and   prepare for operations. Perform system end product
                     Test, Launch      implementation, assembly, integration and test, and
                                       transition to use.

                     Phase E           To conduct the mission and meet the initially identified         Desired system
                     Operations and    need and maintain support for that need. Implement the
                     Sustainment       mission operations plan.

                     Phase F           To implement the systems decommissioning/disposal plan           Product closeout
                     Closeout          developed in Phase E and perform analyses of the returned
                                       data and any returned samples.




processes (steps 1 through 9) in each project phase.                         and closes out (Phase F), the technical work shifts
The SE engine cycles five times from Pre-Phase A                             to activities commensurate with these last two proj-
through Phase D. Note that NASA’s management                                 ect phases. The next major horizontal band shows
has structured Phases C and D to “split” the tech-                           the eight technical management processes (steps 10
nical development processes in half in Phases C and                          through 17) in each project phase. The SE engine
D to ensure closer management control. The engine                            cycles the technical management processes seven
is bound by a dashed line in Phases C and D. Once                            times from Pre-Phase A through Phase F.
a project enters into its operational state (Phase E)




NASA SYSTEMS ENGINEERING HANDBOOK                                                                                                9
