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Design Documentation
Space Power Supplies require extensive
design documentation efforts for two general reasons. The first reason is design disclosure.
This allows the customer to thoroughly review the design and construction prior to hardware
fabrication. The second reason to document all aspects of the unit is for configuration control
and to assure that the unit was built exactly as intended.
A comprehensive documentation program may be streamlined by drawing heavily on existing
engineering documentation. It is important to distinguish between customer review of existing
documentation and customer approval of existing documentation. The former has modest cost impact
as no drawings or procedures will be changed. The latter has greater possibility of cost impact
since changes are usually inherent in the approval. Drawing packages may be generated to DoD-STD-1000
guidelines. There are three levels of drawing packages in this document, Level 1, 2 or 3. Level 1
is an engineering drawing package, and is intended solely for the purposes of design disclosure.
Levels 2 and 3 are suitable for use to document configuration control, as differentiated from design
disclosure packages. Level 3 is the most comprehensive, and theoretically gives sufficient information
for re-procurement if necessary.
The types of drawings contained in a Level 2 or Level 3 package follow a hierarchy, starting
with the outline/ installation drawing, next the top assembly drawing, then the lower level
assemblies. This is followed by detailed fabrication drawings. When components are purchased,
the drawing package includes source and spec. control drawings. These are supplemented by schematics,
block diagrams, manufacturing procedures, etc. Very often, due to schedule requirements, there will be
more than one configuration supplied. In that event, “as built” drawings are provided, depicting
specific configurations.
Schematics and block diagrams are used as tools for design reviews and later analysis.
With space power supplies, if any repairs or modification is required, only the original source
should be entrusted with this work, so schematics and block diagrams are not needed as submittals
for customer maintenance.
Block diagrams and schematics are also useful in conjunction with theories of operation,
which describe how a unit operates.
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