Unformatted text preview: s). In developing the system maintenance
concept, it is useful to consider the mission profile, how
the system will be used, its operational availability goals,
anticipated useful life, and physical environ ments.
Traditionally, a description of the system
maintenance concept is hardware-oriented, though this
need not always be so. The system maintenance
concept is typically described in terms of the anticipated
levels of maintenance (see sidebar on maintenance
levels), general repair policies regarding corrective and
preventive maintenance, assumptions about supply
system responsiveness, the availability of new or
existing facilities, and the maintenance environment.
Initially, the system maintenance concept may be based
on experience with similar systems, but it should not be
exempt from trade studies early in the project life cycle.
These trade studies should focus on the cost
effectiveness of alternative maintenance concepts in the
context of overall system optimization.
Maintenance Levels for
Space Station Alpha Intermediate Depot/
Vendor 6.4.3 Work Performed
On-orbit crew performs ORU Few.
inspections, minor servicing
KSC maintenance facility
repairs ORUs, performs detailed inspections, servicing,
modifications. • More
• Extensive Factory performs major
and complex calibrations.
• The Maintenance Plan, which appears as a major
technical section in the Integrated Logistics Support Designing Maintainable Space
Systems Designing NASA space-based systems for
maintainability will be even more important in the future.
For that reason, the system engineer should be aware of
basic design features that facilitate IVA and EVA
maintenance. Some examples of good practice include: • As with many complex systems, the maintenance concept for Alpha calls for three maintenance levels:
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