Plasma particulate contamination control. I. Transport and process effects

Author(s):  
Gary S. Selwyn
1986 ◽  
Vol 29 (4) ◽  
pp. 19-22
Author(s):  
Suzanne Keilson

Large aerospace assemblies, such as the Optical Telescope Assembly (OTA) for the Hubble Space Telescope built by Perkin-Elmer, present a unique challenge to anyone evaluating clean room products for use on these programs. Very stringent requirements for molecular and particulate contamination control are often not taken into account by the manufacturers of clean room products. The realization that extractables of plastic products pose a serious contamination threat to optical assemblies is gaining wider recognition, but even so-called "solvent compatible" products may not meet the requirements of all sensitive payloads. A process is described for evaluating, selecting and monitoring products in the most widespread use—garments, gloves, and wipers. Notwithstanding well-trained, conscientious personnel, items such as garments, gloves and wipers can be used in such a variety of ways that their tolerance for misuse without untoward consequences must be considered. The final selection process must therefore consider both compatibility and durability and, as was discovered, a unique choice is not always possible for all applications.


2021 ◽  
Vol 2 ◽  
Author(s):  
Jennifer L. Eigenbrode ◽  
Robert Gold ◽  
John S. Canham ◽  
Erich Schulze ◽  
Alfonso F. Davila ◽  
...  

A key science priority for planetary exploration is to search for signs of life in our Solar System. Life-detection mission concepts aim to assess whether or not biomolecular signatures of life are present, which requires highly sensitive instrumentation. This introduces greater risk of false positives, and perhaps false negatives. Stringent science-derived contamination requirements for achieving science measurements on life-detection missions necessitate mitigation approaches that minimize, protect from, and prevent science-relevant contamination of critical surfaces of the science payload and provide high confidence to life-detection determinations. To this end, we report on technology advances that focus on understanding contamination transfer from pre-launch processing to end of mission using high-fidelity physics in the form of computational fluid dynamics and sorption physics for monolayer adsorption/desorption, and on developing a new full-spacecraft bio-molecular barrier design that restricts contamination of the spacecraft and instruments by the launch vehicle hardware. The bio-molecular barrier isolates the spacecraft from biological, molecular, and particulate contamination from the external environment. Models were used to evaluate contamination transport for a designs reference mission that utilizes the barrier. Results of the modeling verify the efficacy of the barrier and an in-cruise decontamination activity. Overall mission contamination tracking from launch to science operations demonstrated exceptionally low probability on contamination impacting science measurements, meeting the stringent contamination requirements of femtomolar levels of compounds. These advances will enable planetary missions that aim to detect and identify signatures of life in our Solar System.


1999 ◽  
Vol 42 (2) ◽  
pp. 32-39
Author(s):  
Glenn Aveni

The contamination control activity performed for the Multi-Angle Imaging Spectro-Radiometer (MISR) consisted of an overall system analysis for susceptibility to molecular and particulate contamination from both internal and external sources at the most sensitive sensor wavelength. This analysis considered the system long and short-term radiometric stability requirements, the expected sources of contaminants, the transport of those contaminants to the sensors, and the expected effects of those contaminants on sensitive surfaces. The derived requirements, including specific budgets, and a plan to meet them during assembly, test, and storage, were documented in the EOS MISR Contamination Control Plan. The final phase of control came from monitoring the hardware (recording data and implementing cleaning procedures) during assembly and thermal vacuum testing prior to shipment to the EOS integrator.


1998 ◽  
Vol 41 (5) ◽  
pp. 31-35 ◽  
Author(s):  
L. Nebenzahl ◽  
R. Nagarajan ◽  
J. Wong ◽  
L. Volpe ◽  
G. Whitney

As we approach the turn of the century, the demand for storage is rapidly increasing, fueled by multimedia and its associated applications. Hard disk drive (HDD) manufacturers continue to respond by chasing the areal density curve to provide higher capacity and higher performance disk drives. The required technology changes are expected to aggravate performance and reliability problems, such as stiction, associated with organic contamination; thermal asperities, associated with particulate contamination; and corrosion, associated with ionic contamination. Anticipation and proactive resolution of chemical integration and contamination control problems are key to the successful development and manufacturing of advanced HDDs. In this paper, types and sources of contamination that can impact HDD performance are described; various contamination-related problems are reviewed; and a methodology by which successful chemical integration in the hard disk drive business can be accomplished is outlined.


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