Page 16 - MEMS and Microstructures in Aerospace Applications

Osiander / MEMS and microstructures in Aerospace applications DK3181_c001 Final Proof page 7 1.9.2005 11:41am

Microelectromechanical Systems and Microstructures in Aerospace Applications 7

1.4.1 AN UNDERSTANDING OF MEMS AND THE MEMS VISION
It is exciting to contemplate the various space mission applications that MEMS
technology could possibly enable in the next 10–20 years. The two primary
objectives of Chapter 2 are to both stimulate ideas for MEMS technology infusion
on future NASA space missions and to spur adoption of the MEMS technology in
the minds of mission designers. This chapter is also intended to inform non-space-
oriented MEMS technologists, researchers, and decision makers about the rich
potential application set that future NASA Science and Exploration missions will
provide. The motivation for this chapter is therefore to lead the reader to identify
and consider potential long-term, perhaps disruptive or revolutionary, impacts that
MEMS technology may have for future civilian space applications. A general
discussion of the potential of MEMS in space applications is followed by a
brief showcasing of a few selected examples of recent MEMS technology develop-
ments for future space missions. Using these recent developments as a point of
departure, a vision is then presented of several areas where MEMS technology
might eventually be exploited in future science and exploration mission applica-
tions. Lastly, as a stimulus for future research and development, this chapter
summarizes a set of barriers to progress, design challenges, and key issues that
must be overcome for the community to move on from the current nascent phase of
developing and infusing MEMS technology into space missions, in order to achieve
its full potential.
Chapter 3 discusses the fundamentals of the three categories of MEMS fabri-
cation processes. Bulk micromachining, sacrificial surface micromachining, and
LIGA have differing capabilities that include the achievable device aspect ratio,
materials, complexity, and the ability to integrate with microelectronics. These
differing capabilities enable their application to a range of devices. Commercially
successful MEMS devices include pressure sensors, accelerometers, gyroscopes,
and ink-jet nozzles. Two notable commercial successes include the Texas Instru-
1 1
ments Digital Mirror Device (DMD ) and the Analog Devices ADXL acceler-
ometers and gyroscopes. The paths for the integration of MEMS as well as some of
the advanced materials that are being developed for MEMS applications are dis-
cussed.
Chapter 4 discusses the space environment and its effects upon the design,
including material selection and manufacturing controls for MEMS. It provides a
cursory overview of the thermal, mechanical, and chemical effects that may impact
the long-term reliability of the MEMS devices, and reviews the storage and
application conditions that the devices will encounter. Space-mission environmen-
tal influences, radiation, zero gravity, zero pressure, plasma, and atomic oxygen and
their potential concerns for MEMS designs and materials selection are discussed.
Long-life requirements are included as well. Finally, with an understanding of the
concerns unique to hardware for space environment operation, materials selection is
included. The user is cautioned that this chapter is barely an introduction, and
should be used in conjunction with the sections of this book covering reliability,
packaging, contamination, and handling concerns.

© 2006 by Taylor & Francis Group, LLC