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366 MEMS and Microstructures in Aerospace Applications

host vehicle. Mission integration and test practices and procedures will be the over
arching guidance for all activity in the I&T phase. The I&T phase may provide
potentially detrimental handling, storage, and test conditions. Caution should be
exercised to assure protection from moisture and contaminants of MEMS devices.
The use of red tag items (covers and protective devices) that will be removed
prior to flight is encouraged. The provider must be prepared for excessively long
storage periods that have been caused by drawn-out flight schedule delays.
Although I&T is performed in a controlled environment, conditions during test
may change dramatically and storage conditions will be less controlled. Storage due
to standdown time of launch vehicles has traditionally varied from 4 months to
close to 3 years. 12
The qualification test of a spacecraft is a lengthy and demanding process.
Besides proving the design, the entirety is demonstrated for the first time. The
qualification test sequence normally matches the expected flight sequence: vibra-
tion, shock, and thermal vacuum. We may also configure the spacecraft to match
the operational sequence by folding the solar array and deployables during the
vibration and test and deploying or removing them during thermal vacuum. 13
Any susceptibility of the MEMS during these tests should be identified and
planned for early. The design may need to have aliveness test points rather than test
MEMS out of a vacuum. The whole life cycle must be planned early to prevent
problems encountered late in the build.

16.7 CONCLUSION
The lack of historical data and well-defined test methodologies for the emerging
MEMS in space presents a problem for the flight assurance manager, quality
engineer, and program manager among others. The well-defined military and
aerospace microcircuit world forms the basis for assurance requirements for micro-
electromechanical devices. This microcircuit base, with its well-defined specifica-
tions and standards, is supplemented with MEMS-specific testing along with the
end item application testing as close to a relevant environment as possible. This
chapter provides a guideline for the user rather than a prescription; that is, each
individual application will need tailored assurance requirements to meet the needs
associated with each unique situation.

REFERENCES
1. Hartzell, A. and Woodilla, D., MEMS reliability, characterization and test, Presented at
Reliability, Testing, and Characterization of MEMS/MOEMS, San Francisco, CA,
October 22–24, 2001.
2. Pfeifer, T. et al., Quality control and process observation for the micro assembly process,
Measurement: Journal of the International Measurement Confederation, 30(1), 1, 2001.
3. Ermolov, V. et al., MEMS for mobile communications, Circuits Assembly, 13(7), 46,
2002.

© 2006 by Taylor & Francis Group, LLC