MEMS and Microstructures in Aerospace Applications - Robert Osiander et al (Eds) Part 1 pptx

A CRC title, part of the Taylor & Francis imprint, a member of the
Taylor & Francis Group, the academic division of T&F Informa plc.
MEMS and
Microstructures

in

Aerospace
Applications
Edited by
Robert Osiander
M. Ann Garrison Darrin
John L. Champion
Boca Raton London New York
© 2006 by Taylor & Francis Group, LLC
Published in 2006 by
CRC Press
Taylor & Francis Group
6000 Broken Sound Parkway NW, Suite 300
Boca Raton, FL 33487-2742
© 2006 by Taylor & Francis Group, LLC
CRC Press is an imprint of Taylor & Francis Group
No claim to original U.S. Government works
Printed in the United States of America on acid-free paper
10987654321
International Standard Book Number-10: 0-8247-2637-5 (Hardcover)
International Standard Book Number-13: 978-0-8247-2637-9 (Hardcover)
Library of Congress Card Number 2005010800
This book contains information obtained from authentic and highly regarded sources. Reprinted material is
quoted with permission, and sources are indicated. A wide variety of references are listed. Reasonable efforts
have been made to publish reliable data and information, but the author and the publisher cannot assume

responsibility for the validity of all materials or for the consequences of their use.
No part of this book may be reprinted, reproduced, transmitted, or utilized in any form by any electronic,
mechanical, or other means, now known or hereafter invented, including photocopying, microfilming, and
recording, or in any information storage or retrieval system, without written permission from the publishers.
For permission to photocopy or use material electronically from this work, please access www.copyright.com
( or contact the Copyright Clearance Center, Inc. (CCC) 222 Rosewood Drive,
Danvers, MA 01923, 978-750-8400. CCC is a not-for-profit organization that provides licenses and registration
for a variety of users. For organizations that have been granted a photocopy license by the CCC, a separate
system of payment has been arranged.
Trademark Notice: Product or corporate names may be trademarks or registered trademarks, and are used only
for identification and explanation without intent to infringe.
Library of Congress Cataloging-in-Publication Data
Osiander, Robert.
MEMS and microstructures in aerospace applications / Robert Osiander, M. Ann Garrison Darrin,
John Champion.
p. cm.
ISBN 0-8247-2637-5
1. Aeronautical instruments. 2. Aerospace engineering Equipment and supplies. 3.
Microelectromechanical systems. I. Darrin, M. Ann Garrison. II. Champion, John. III. Title.
TL589.O85 2005
629.135 dc22 2005010800
Visit the Taylor & Francis Web site at

and the CRC Press Web site at

Taylor & Francis Group
is the Academic Division of T&F Informa plc.
© 2006 by Taylor & Francis Group, LLC
Preface
MEMS and Microstructures in Aerospace Applications is written from a program-

matic requirements perspective. MEMS is an interdisciplinary field requiring
knowledge in electronics, micromechanisms, processing, physics, fluidics, pack-
aging, and materials, just to name a few of the skills. As a corollary, space missions
require an even broader range of disciplines. It is for this broad group and especially
for the system engineer that this book is written. The material is designed for the
systems engineer, flight assurance manager, project lead, technologist, program
management, subsystem leads and others, including the scientist searching for
new instrumentation capabilities, as a practical guide to MEMS in aerospace
applications. The objective of this book is to provide the reader with enough
background and specific information to envision and support the insertion of
MEMS in future flight missions. In order to nurture the vision of using MEMS in
microspacecraft — or even in spacecraft — we try to give an overview of some of
the applications of MEMS in space to date, as well as the different applications
which have been developed so far to support space missions. Most of these
applications are at low-technology readiness levels, and the expected next step is
to develop space qualified hardware. However, the field is still lacking a heritage
database to solicit prescriptive requirements for the next generation of MEMS
demonstrations. (Some may argue that that is a benefit.) The second objective of
this book is to provide guidelines and materials for the end user to draw upon to
integrate and qualify MEMS devices and instruments for future space missions.
Osiander / MEMS and microstructures in Aerospace applications DK3181_prelims Final Proof page iii 1.9.2005 8:59pm
© 2006 by Taylor & Francis Group, LLC
Editors
Robert Osiander received his Ph.D. at the Technical University in Munich,
Germany, in 1991. Since then he has worked at JHU/APL’s Research and Tech-
nology Development Center, where he became assistant supervisor for the sensor
science group in 2003, and a member of the principal professional staff in 2004.
Dr. Osiander’s current research interests include microelectromechanical systems
(MEMS), nanotechnology, and Terahertz imaging and technology for applications
in sensors, communications, thermal control, and space. He is the principal inves-

tigator on ‘‘MEMS Shutters for Spacecraft Thermal Control,’’ which is one of
NASA’s New Millenium Space Technology Missions, to be launched in 2005.
Dr. Osiander has also developed a research program to develop carbon nanotube
(CNT)-based thermal control coatings.
M. Ann Garrison Darrin is a member of the principal professional staff and is a
program manager for the Research and Technology Development Center at The
Johns Hopkins University Applied Physics Laboratory. She has over 20 years
experience in both government (NASA, DoD) and private industry in particular
with technology development, application, transfer, and insertion into space flight
missions. She holds an M.S. in technology management and has authored several
papers on technology insertion along with coauthoring several patents. Ms. Darrin
was the division chief at NASA’s GSFC for Electronic Parts, Packaging and
Material Sciences from 1993 to 1998. She has extensive background in aerospace
engineering management, microelectronics and semiconductors, packaging, and
advanced miniaturization. Ms. Darrin co-chairs the MEMS Alliance of the Mid
Atlantic.
John L. Champion is a program manager at The Johns Hopkins University Applied
Physics Laboratory (JHU/APL) in the Research and Technology Development
Center (RTDC). He received his Ph.D. from The Johns Hopkins University, De-
partment of Materials Science, in 1996. Dr. Champion’s research interests include
design, fabrication, and characterization of MEMS systems for defense and space
applications. He was involved in the development of the JHU/APL Lorentz force
xylophone bar magnetometer and the design of the MEMS-based variable reflect-
ivity concept for spacecraft thermal control. This collaboration with NASA–GSFC
was selected as a demonstration technique on one of the three nanosatellites for the
New Millennium Program’s Space Technology-5 (ST5) mission. Dr. Champion’s
graduate research investigated thermally induced deformations in layered struc-
tures. He has published and presented numerous papers in his field.
Osiander / MEMS and microstructures in Aerospace applications DK3181_prelims Final Proof page v 1.9.2005 8:59pm
© 2006 by Taylor & Francis Group, LLC

Contributors
James J. Allen
Sandia National Laboratory
Albuquerque, New Mexico
Bradley G. Boone
The Johns Hopkins University Applied
Physics Laboratory
Laurel, Maryland
Stephen P. Buchner
NASA Goddard Space Flight Center
Greenbelt, Maryland
Philip T. Chen
NASA Goddard Space Flight Center
Greenbelt, Maryland
M. Ann Garrison Darrin
The Johns Hopkins University Applied
Physics Laboratory
Laurel, Maryland
Cornelius J. Dennehy
NASA Goddard Space Flight Center
Greenbelt, Maryland
Dawnielle Farrar
The Johns Hopkins University Applied
Physics Laboratory
Laurel, Maryland
Samara L. Firebaugh
United States Naval Academy
Annapolis, Maryland
Thomas George
Jet Propulsion Laboratory

Pasadena, California
R. David Gerke
Jet Propulsion Laboratory
Pasadena, California
Brian Jamieson
NASA Goddard Space Flight Center
Greenbelt, Maryland
Robert Osiander
The Johns Hopkins University Applied
Physics Laboratory
Laurel, Maryland
Robert Powers
Jet Propulsion Laboratory
Pasadena, California
Keith J. Rebello
The Johns Hopkins University Applied
Physics Laboratory
Laurel, Maryland
Jochen Schein
Lawrence Livermore National
Laboratory
Livermore, California
Theodore D. Swanson
NASA Goddard Space Flight Center
Greenbelt, Maryland
Danielle M. Wesolek
The Johns Hopkins University Applied
Physics Laboratory
Laurel, Maryland
Osiander / MEMS and microstructures in Aerospace applications DK3181_prelims Final Proof page vii 1.9.2005 8:59pm

© 2006 by Taylor & Francis Group, LLC
Acknowledgments
Without technology champions, the hurdles of uncertainty and risk vie with cer-
tainty and programmatic pressure to prevent new technology insertions in space-
craft. A key role for these champions is to prevent obstacles from bringing
development and innovation to a sheer halt.
The editors have been fortunate to work with the New Millennium Program
(NMP) Team for Space Technology 5 (ST5) at the NASA Goddard Space Flight
Center (GSFC). In particular, Ted Swanson, as technology champion, and Donya
Douglas, as technology leader, created an environment that balanced certainty,
uncertainties, risks and pressures for ST5, micron-scale machines open and close
to vary the emissivity on the surface of a microsatellite radiator. These ‘‘VARI-E’’
microelectromechanical systems (MEMS) are a result of collaboration between
NASA, Sandia National Laboratories, and The Johns Hopkins University Applied
Physics Laboratory (JHU/APL). Special thanks also to other NASA ‘‘tech cham-
pions’’ Matt Moran (Glenn Research Center) and Fred Herrera (GSFC) to name a
few! Working with technology champions inspired us to realize the vast potential of
‘‘small’’ in space applications.
A debt of gratitude goes to our management team Dick Benson, Bill D’Amico,
John Sommerer, and Joe Suter and to the Johns Hopkins University Applied Physics
Laboratory for its support through the Janney Program. Our thanks are due to all the
authors and reviewers, especially Phil Chen, NASA, in residency for a year at the
laboratory. Thanks for sharing in the pain.
There is one person for whom we are indentured servants for life, Patricia M.
Prettyman, whose skills and abilities were and are invaluable.
Osiander / MEMS and microstructures in Aerospace applications DK3181_prelims Final Proof page ix 1.9.2005 8:59pm
© 2006 by Taylor & Francis Group, LLC
Contents
Chapter 1
Overview of Microelectromechanical Systems and Microstructures

in Aerospace Applications 1
Robert Osiander and M. Ann Garrison Darrin
Chapter 2
Vision for Microtechnology Space Missions 13
Cornelius J. Dennehy
Chapter 3
MEMS Fabrication 35
James J. Allen
Chapter 4
Impact of Space Environmental Factors on Microtechnologies 67
M. Ann Garrison Darrin
Chapter 5
Space Radiation Effects and Microelectromechanical Systems 83
Stephen P. Buchner
Chapter 6
Microtechnologies for Space Systems 111
Thomas George and Robert Powers
Chapter 7
Microtechnologies for Science Instrumentation Applications 127
Brian Jamieson and Robert Osiander
Chapter 8
Microelectromechanical Systems for Spacecraft Communications 149
Bradley Gilbert Boone and Samara Firebaugh
Chapter 9
Microsystems in Spacecraft Thermal Control 183
Theodore D. Swanson and Philip T. Chen
Osiander / MEMS and microstructures in Aerospace applications DK3181_prelims Final Proof page xi 1.9.2005 8:59pm
© 2006 by Taylor & Francis Group, LLC
Chapter 10
Microsystems in Spacecraft Guidance, Navigation, and Control 203

Cornelius J. Dennehy and Robert Osiander
Chapter 11
Micropropulsion Technologies 229
Jochen Schein
Chapter 12
MEMS Packaging for Space Applications 269
R. David Gerke and Danielle M. Wesolek
Chapter 13
Handling and Contamination Control Considerations
for Critical Space Applications 289
Philip T. Chen and R. David Gerke
Chapter 14
Material Selection for Applications of MEMS 309
Keith J. Rebello
Chapter 15
Reliability Practices for Design and Application of Space-Based MEMS 327
Robert Osiander and M. Ann Garrison Darrin
Chapter 16
Assurance Practices for Microelectromechanical Systems
and Microstructures in Aerospace 347
M. Ann Garrison Darrin and Dawnielle Farrar
Osiander / MEMS and microstructures in Aerospace applications DK3181_prelims Final Proof page xii 1.9.2005 8:59pm
© 2006 by Taylor & Francis Group, LLC
1
Overview of
Microelectromechanical
Systems and
Microstructures in
Aerospace Applications
Robert Osiander and M. Ann Garrison Darrin

CONTENTS
1.1 Introduction 1
1.2 Implications of MEMS and Microsystems in Aerospace 2
1.3 MEMS in Space 4
1.3.1 Digital Micro-Propulsion Program STS-93 4
1.3.2 Picosatellite Mission 5
1.3.3 Scorpius Sub-Orbital Demonstration 5
1.3.4 MEPSI 5
1.3.5 Missiles and Munitions — Inertial Measurement Units 6
1.3.6 OPAL, SAPPHIRE, and Emerald 6
1.3.7 International Examples 6
1.4 Microelectromechanical Systems and Microstructures
in Aerospace Applications 6
1.4.1 An Understanding of MEMS and the MEMS Vision 7
1.4.2 MEMS in Space Systems and Instrumentation 8
1.4.3 MEMS in Satellite Subsystems 9
1.4.4 Technical Insertion of MEMS in Aerospace Applications 10
1.5 Conclusion 11
References 12
The machine does not isolate man from the great problems of nature but plunges him
more deeply into them.
Saint-Exupe
´
ry, Wind, Sand, and Stars, 1939
1.1 INTRODUCTION
To piece together a book on microelectromechanical systems (MEMS) and micro-
structures for aerospace applications is perhaps foolhardy as we are still in the
Osiander / MEMS and microstructures in Aerospace applications DK3181_c001 Final Proof page 1 1.9.2005 11:41am
1
© 2006 by Taylor & Francis Group, LLC

When we think of MEMS or micromachining, wrist and pocket watches do not
necessarily come to our mind. While these devices often are a watchmaker’s piece
of art, they are a piece of their own, handcrafted in single numbers, none like the
other. Today, one of the major aspects of MEMS and micromachining is batch
processing, producing large numbers of devices with identical properties, at the
same time assembled parallel in automatic processes. The introduction of micro-
electronics into watches has resulted in better watches costing a few dollars instead
of a few thousand dollars, and similarly the introduction of silicon surface micro-
machining on the wafer level has reduced, for example, the price of an accelerom-
eter, the integral part of any car’s airbag, to a few dimes.
Spacecraft application of micromachined systems is different in the sense that
batch production is not a requirement in the first place — many spacecraft and the
applications are unique and only produced in a small number. Also, the price tag is
often not based on the product, but more or less determined by the space qualifi-
cation and integration into the spacecraft. Reliability is the main issue; there is
typically only one spacecraft and it is supposed to work for an extended time
without failure.
In addition, another aspect in technology development has changed over time.
The race into space drove miniaturization, electronics, and other technologies.
Many enabling technologies for space, similar to the development of small chro-
nometers in the 15th and 16th centuries, allowed longitude determination, brought
accurate navigation, and enabled exploration. MEMS (and we will use MEMS to
refer to any micromachining technique) have had their success in the commercial
industries — automotive and entertainment. There, the driver as in space is cost,
and the only solution is mass production. Initially pressure sensors and later
accelerometers for the airbag were the big successes for MEMS in the automotive
industry which reduced cost to only a few dimes. In the entertainment industry,
Texas Instruments’ mirror array has about a 50% market share (the other devices
used are liquid crystal-based electronic devices), and after an intense but short
development has helped to make data projectors available for below $1000 now.

One other MEMS application which revolutionized a field is uncooled IR detectors.
Without sensitivity losses, MEMS technology has also reduced the price of this
equipment by an order of magnitude, and allowed firefighters, police cars, and
luxury cars to be equipped with previously unaffordable night vision. So the
question is, what does micromachining and MEMS bring to space?
Key drivers of miniaturization of microelectronics are the reduced cost and
mass production. These drivers combine with the current significant trend to
integrate more and more components and subsystems into fewer and fewer chips,
enabling increased functionality in ever-smaller packages. MEMS and other sensors
and actuator technologies allow for the possibility of miniaturizing and integrating
entire systems and platforms. This combination of reduced size, weight, and cost
per unit with increased functionality has significant implications for Air Force
missions, from global reach to situational awareness and to corollary civilian
scientific and commercial based missions. Examples include the rapid low-cost
global deployment of sensors, launch-on-demand tactical satellites, distributed
Osiander / MEMS and microstructures in Aerospace applications DK3181_c001 Final Proof page 3 1.9.2005 11:41am
Microelectromechanical Systems and Microstructures in Aerospace Applications 3
© 2006 by Taylor & Francis Group, LLC
2
Vision for
Microtechnology Space
Missions
Cornelius J. Dennehy
CONTENTS
2.1 Introduction 13
2.2 Recent MEMS Technology Developments for Space Missions 16
2.2.1 NMP ST5 Thermal Louvers 16
2.2.2 JWST Microshutter Array 18
2.2.3 Inchworm Microactuators 20
2.2.4 NMP ST6 Inertial Stellar Camera 21

2.2.5 Microthrusters 23
2.2.6 Other Examples of Space MEMS Developments 23
2.3 Potential Space Applications for MEMS Technology 25
2.3.1 Inventory of MEMS-Based Spacecraft Components 26
2.3.2 Affordable Microsatellites 26
2.3.3 Science Sensors and Instrumentation 27
2.3.4 Exploration Applications 28
2.3.5 Space Particles or Morphing Entities 28
2.4 Challenges and Future Needs 29
2.4.1 Challenges 29
2.4.2 Future Needs 29
2.5 Conclusions 32
References 33
2.1 INTRODUCTION
We live in an age when technology developments combined with the innate human
urge to imagine and innovate are yielding astounding inventions at an unpreced-
ented rate. In particular, the past 20 years have seen a disruptive technology called
microelectromechanical systems (MEMS) emerge and blossom in multiple ways.
The commercial appeal of MEMS technologies lies in their low cost in high-volume
production, their inherent miniature-form factor, their ultralow mass and power,
their ruggedness, all with attendant complex functionality, precision, and accuracy.
We are extremely interested in utilizing MEMS technology for future space mission
for some of the very same reasons.
Osiander / MEMS and microstructures in Aerospace applications DK3181_c002 Final Proof page 13 1.9.2005 11:49am
13
© 2006 by Taylor & Francis Group, LLC
Recently dramatic progress has been occurring in the development of
ultraminiature, ultralow power, and highly integrated MEMS-based microsystems
that can sense their environment, process incoming information, and respond in a
precisely controlled manner. The capability to communicate with other microscale

devices and, depending on the application, with the macroscale platforms they are
hosted on, will permit integrated and collaborative system-level behaviors. These
attributes, combined with the potential to generate power on the MEMS scale,
provide a potential for MEMS-based microsystems not only to enhance, or even
replace, today’s existing macroscale systems but also to enable entirely new classes
of microscale systems.
As described in detail in subsequent chapters of this book, the roots of the
MEMS technology revolution can be found in the substantial surface (planar)
micromachining technology investments made over the last 30 years by integrated
circuit (IC) semiconductor production houses worldwide. Broadly speaking, it is also
a revolution that exploits the integration of multidisciplinary engineering processes
and techniques at the submillimeter (hundreds of microns) device size level. The
design and development of MEMS devices leverages heavily off of well-established,
and now standard, techniques and processes for 2-D and 3-D semiconductor fabrica-
tion and packaging. MEMS technology will allow us to field new generations of
sensors and devices in which the functions of detecting, sensing, computing, actuat-
ing, controlling, communicating, and powering are all colocated in assemblies or
structures with dimensions of the order of 100–200 mm or less.
Over the past several years, industry analysts and business research organizations
have pointed to the multibillion dollar-sized global commercial marketplace for
MEMS-based devices and microsystems in such areas as the automotive industry,
communications, biomedical, chemical, and consumer products. The MEMS-
enabled ink jet printer head and the digital micromirror projection displays are
often cited examples of commercially successful products enabled by MEMS
technology. Both the MEMS airbag microaccelerometer and the tire air-pressure
sensors are excellent examples of commercial applications of MEMS in the automo-
tive industry sector. Implantable blood pressure sensors and fluidic micropumps for
in situ drug delivery are examples of MEMS application in the biomedical arena.
Given the tremendous rapid rate of technology development and adoption over
the past 100 years, one can confidently speculate that MEMS technology, especially

when coupled with the emerging developments in nanoelectromechanical systems
(NEMS) technology, has the potential to change society as did the introduction of the
telephone in 1876, the tunable radio receiver in 1916, the electronic transistor in 1947,
and the desktop personal computer (PC) in the 1970s. In the not too distant future,
once designers and manufacturers become increasingly aware of the possibilities that
arise from this technology, it may well be that MEMS-based devices and microsys-
tems become as ubiquitous and as deeply integrated in our society’s day-to-day
existence as the phone, the radio, and the PC are today.
Perhaps it is somewhat premature to draw MEMS technology parallels to the
technological revolutions initiated by such — now commonplace — household
electronics. It is, however, very probable that as more specific commercial
Osiander / MEMS and microstructures in Aerospace applications DK3181_c002 Final Proof page 14 1.9.2005 11:49am
14 MEMS and Microstructures in Aerospace Applications
© 2006 by Taylor & Francis Group, LLC
applications are identified where MEMS is clearly the competitively superior
alternative, and the low-cost fabrication methods improve in device quality and
reliability, and industry standard packaging and integration solutions are formu-
lated, more companies focusing solely on commercializing MEMS technology will
emerge and rapidly grow to meet the market demand. What impact this will have on
society is unknown, but it is quite likely that MEMS (along with NEMS), will have
an increasing presence in our home and our workplace as well as in many points
in between. One MEMS industry group has gone so far as to predict that before
2010 there will be at least five MEMS devices per person in use in the United States.
It is not the intention of this chapter to comprehensively describe the far-
reaching impact of MEMS-based microsystems on humans in general. This is
well beyond the scope of this entire book, in fact. The emphasis of this chapter
is on how the space community might leverage and exploit the billion-dollar
worldwide investments being made in the commercial (terrestrial) MEMS industry
for future space applications. Two related points are relevant in this context.
First, it is unlikely that without this significant investment in commercial

MEMS, the space community would even consider MEMS technology. Second,
the fact that each year companies around the world are moving MEMS devices out
of their research laboratories into commercial applications — in fields such as
biomedicine, optical communications, and information technology — at an increas-
ing rate can only be viewed as a very positive influence on transitioning MEMS
technology toward space applications. The global commercial investments in
MEMS have created the foundational physical infrastructure, the highly trained
technical workforce, and most importantly, a deep scientific and engineering
knowledge base that will continue to serve, as the strong intellectual spring-
board for the development of MEMS devices and microsystems for future space
applications.
Two observations can be made concerning the differences between MEMS
in the commercial world and the infusion of MEMS into space missions. First,
unlike the commercial marketplace where very high-volume production and con-
sumption is the norm, the niche market demand for space-qualified MEMS devices
will be orders of magnitude less. Second, it is obvious that transitioning commercial
MEMS designs to the harsh space environment will not be necessarily trivial. Their
inherent mechanical robustness will clearly be a distinct advantage in surviving the
dynamic shock and vibration exposures of launch, orbital maneuvering, and lunar or
planetary landing. However, it is likely that significant modeling, simulation,
ground test, and flight test will be needed before space-qualified MEMS devices,
which satisfy the stringent reliability requirements traditionally imposed upon space
platform components, can routinely be produced in reasonable volumes. For ex-
ample, unlike their commercial counterparts, space MEMS devices will need to
simultaneously provide radiation hardness (or at least radiation tolerance), have the
capability to operate over wide thermal extremes, and be insensitive to significant
electrical or magnetic fields.
In the remainder of this chapter, recent examples of MEMS technologies
being developed for space mission applications are discussed. The purpose of
Osiander / MEMS and microstructures in Aerospace applications DK3181_c002 Final Proof page 15 1.9.2005 11:49am

Vision for Microtechnology Space Missions 15
© 2006 by Taylor & Francis Group, LLC
Center (GSFC), developed by the Johns Hopkins University Applied Physics
Laboratory (JHU/APL) and fabricated at the Sandia National Laboratory. In JHU/
APL’s rendition, the radiator is coated with arrays of micro-machined shutters, which
can be independently controlled with electrostatic actuators, and which controls the
apparent emittance of the radiator.
1
The latest prototype devices are 1.8 mm  0.88
mm arrays of 150 Â 6 mm shutters that are actuated by electrostatic comb drives to
expose either the gold coating or the high-emittance substrate itself to space. Figure
2.2 shows an actuator block with the arrays. Prototype arrays designed by JHU/APL
have been fabricated at the Sandia National Laboratories using their SUMMiT V
1
process. For the flight units, about 38 dies with 72 shutter arrays each will be
combined on a radiator and independently controlled.
The underlying motivation for this particular technology can be summarized as
follows: Most spacecraft rely on radiative surfaces (radiators) to dissipate waste
heat. These radiators have special coatings that are intended to optimize perform-
ance under the expected heat load and thermal sink environment. Typically, such
radiators will have a low absorptivity and a high infrared emissivity. Given the
variable dynamics of the heat loads and thermal environment, it is often a challenge
to properly size the radiator. For the same reasons, it is often necessary to have
some means of regulating the heat-rejection rate in order to achieve proper thermal
FIGURE 2.1 The NMP ST5 Project is designing and building three miniature satellites that
are approximately 54 cm in diameter and 28 cm in height with a mass less than 25 kg per
vehicle. (Source: NASA.)
Osiander / MEMS and microstructures in Aerospace applications DK3181_c002 Final Proof page 17 1.9.2005 11:49am
Vision for Microtechnology Space Missions 17
© 2006 by Taylor & Francis Group, LLC