Page 79 - MEMS and Microstructures in Aerospace Applications

Osiander / MEMS and microstructures in Aerospace applications DK3181_c004 Final Proof page 67 25.8.2005 3:40pm

4 Impact of Space

Environmental Factors on

Microtechnologies

M. Ann Garrison Darrin

CONTENTS

4.1 Introduction.................................................................................................... 67
4.2 Mechanical, Chemical, and Electrical Stresses ............................................ 68
4.2.1 Thermal Mechanical Effects.............................................................. 68
4.2.2 Mechanical Effects of Shock, Acceleration, and Vibration.............. 71
4.2.3 Chemical Effects................................................................................ 72
4.2.4 Electrical Stresses .............................................................................. 73
4.3 Design through Mission Operation Environments........................................ 74
4.4 Space Mission-Specific Environmental Concerns........................................ 76
4.5 Conclusion ..................................................................................................... 81
4.6 Military Specifications and Standards Referenced....................................... 81
References............................................................................................................... 82

4.1 INTRODUCTION
Microelectromechanical systems (MEMS) devices used in space missions are
exposed to many different types of environments. These environments include
manufacturing, assembly, and test and qualification at the part, board, and assembly
levels. Subsystem and system level environments include prelaunch, launch, and
mission. Each of these environments contributes unique stress factors. An overview
of these stress factors is given along with a discussion of the environments.
For space flight applications, microelectronic devices are often standard parts in
accordance with NASA and Department of Defense (DoD)-generated specifications.
Standard parts are required to be designed and tested for high reliability and long life
through all phases of usage including storage, test, and operation. In contrast, there
are no standard components in the MEMS arena for space flight application and no
great body of knowledge or years of historical data and de-rating systems to depend
on when addressing concerns for inserting devices in critical missions.
Civilian and military space missions impose strict design requirements for
systems to stay within the allocations for size, weight, cost, and power. In addition,
each system must meet the life expectancy requirements of the mission. Life

67

© 2006 by Taylor & Francis Group, LLC