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Handling and Contamination Control for Critical Space Applications 295

In general, the following measures can help reduce or eliminate ESD problems
in device manufacturing and test areas:

. Ensure that all workstations are static-free
. Handle devices only at static-free workstations
. Implement ESD training for all operators
. Control RH to within 40 to 60%
. Transport all devices in static-free containers
. Ground yourself before handling devices

Because of the catastrophic failure caused by ESD, all personnel who work with
MEMS should be trained in the proper procedures for handling the devices.
Furthermore, these procedures should be documented and readily available for
reference. Typically, the procedures include the methods, equipment, and materials
used in the handling, packaging, and testing of MEMS. Further guidance for device
handling is available in the Electronics Industry Association JEDEC Publication
8
EIA 625 and MIL-STD-1686. 9

13.6 CONTAMINATION CONTROL
In aerospace applications, contaminants are commonly referred to as any undesired
foreign materials which emerge at any phase of a mission. The presence of
contaminants, either molecules or particles, degrades the performance of hardware
to various degrees of severity. In a worst-case scenario, contaminants may render an
instrument worth millions of dollars useless. As a result, maintaining hardware to its
designed cleanliness conditions through all mission phases becomes a demanding
task. Therefore, an effective contamination control program starts with conceptual
design phase of the mission and proceeds through its on-orbit operations.

13.6.1 CONTAMINATION CONTROL PROGRAM
The effort of contamination control depends on the specific mission goals, instru-
ment designs, and planned operating scenarios. This dependence may be simply
interpreted as the ‘‘contamination sensitivity’’ of the mission. It is noticeable that a
mission with high contamination sensitivity requires a more elaborate contamin-
ation control effort. In the cases of payloads which are not sensitive to conta-
mination, this program may still be required due to cross-contamination potentials
to other payloads or orbiter systems. The contamination control program is applic-
able to all payloads, subsystems, instruments, and components during all mission
phases. A typical mission, small or big, consists of sequential phases from its
conceptual design, fabrication, assembly, integration and test, storage, transport,
launch site preparation, launch, to its on-orbit operations. In certain occasions, the
last phase of contamination control is extended to handle space-returned hardware
such as the investigation of the returned hardware of the Long Duration Exposure
Facility (LDEF) mission. To accomplish contamination control, it is necessary for

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