Unformatted text preview: grated into the design, and the manufacturing
process and controls are defined and validated.
Configuration management continues to track and
control design changes as detailed interfaces are
defined. At each step in the successive refinement of
the final design, corresponding integration and
verification activities are planned in greater detail.
During this phase, technical parameters, schedules, and
budgets are closely tracked to ensure that undesirable
trends (such as an unexpected growth in spacecraft
mass or increase in its cost) are recognized early
enough to take corrective action. (See Section 4.9.)
Phase C culminates in a series of critical design
reviews (CDRs) containing the system-level CDR and
CDRs corresponding to the different levels of the
system hierarchy. The CDR is held prior to the start of
fabrication/production of end items for hardware and
prior to the start of coding of deliverable software
products. Typically, the sequence of CDRs reflects the
integration process that will occur in the next phase—
that is, from lower-level CDRs to the system-level CDR.
Projects, however, should tailor the sequencing of the
reviews to meet their individual needs. The final product
of this phase is a "build-to" baseline in sufficient detail
that actual production can proceed. NASA Systems Engineering Handbook
The Project Life Cycle for Major NASA Systems
Purpose: To complete the detailed design of the system (and its associated subsystems, including
its operations systems).
Major Activities and their Products:
Add remaining lower-level design specificationsto the
Refine requirements documents
Refine verification plans
Prepare interface documents
(Repeat the process of successive refinement to get
"build-to" specifications and drawings,
verification plans, and interface documents at
Augment baselined documents to reflect the growing
maturity of the system: system architecture,
verification requirements matrix, work
breakdown structure, project plans...
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