PSAM 16 Conference Paper Overview
Welcome to the PSAM 16 Conference paper and speaker overview page.
Lead Author: Arman Seuylemezian Co-author(s): Arman Seuylemezian- arman.seuylemezian@jpl.nasa.gov
Amy Baker- amy.l.baker@nasa.gov
Christine Moissl-Eichinger - christine.moissl-eichinger@medunigraz.at
| Probabilistic Modeling of Recovery Efficiency of Sampling Devices used in Planetary Protection Bioburden Estimation |
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| Microbial contamination has been of concern to the planetary protection (PP) discipline since the Viking missions in the 1970s. In order to mitigate this risk and ensure compliance with international policy, the PP discipline continually monitors the microbial bioburden present on spacecraft and associated surfaces. Spacecraft missions destined for other planetary bodies must abide by a set of requirements put forth by NASA based on recommendations from the Committee on Space Research (COSPAR). Compliance to these biological cleanliness requirements are demonstrated by direct sampling of spacecraft hardware and associated surfaces to enumerate the number of microorganisms present on the surface. The PP discipline has employed a variety of tools to perform direct sampling including four different types of swabs (Cotton Puritan, Cotton Copan, Polyester, and Nylon Flocked) as well as two different types of wipes including (TX3211, and TX3224) which are typically used to sample surfaces no larger than 25 cm2 and 1 m2 respectively. The sampling efficiency of these devices is a critical parameter used to generate spacecraft level cleanliness estimates. In this study, we investigate how recovery efficiency differs by inoculum amount and species. This is analyzed across different sampling devices using a set of microbial organisms applied to stainless steel surfaces. Two different recovery techniques were employed the NASA standard assay as well as the European Space Agency (ESA) standard assay and two different techniques for plating: Milliflex filtration method and direct plating. Data were analyzed by first developing a probabilistic model of the end-to-end experimental process capturing uncertainty from the inoculation of species onto the coupon through recovery and growth. The model was aimed to quantify the mean recovery efficiency, a key metric for understanding the probability that an individual microorganism is recovered and predicting the number of microorganisms present on a surface. A cost function was developed to compare the recovery efficiency of various sampling devices and processes and identify those that provide optimal bioburden estimation capability. The results suggest the nylon flocked swab and the TX 3211 wipe yielded the highest recovery efficiency and optimal bioburden estimation capability. Results from this study will be integrated into the Bayesian statistical framework used to perform bioburden calculations for demonstrating PP requirements compliance. |
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Author and Presentation Info
Lead Author Name: Arman Seuylemezian (arman.seuylemezian@jpl.nasa.gov)
Bio: Arman has been a research scientist with the Biotechnology and Planetary Protection group at JPL for the past 5 years with a background in microbiology and bioinformatics. His work encompasses all aspects of planetary protection including bacterial detection and enumeration using both traditional culture based techniques and molecular methods. Arman has experience in the development of microbial reduction modalities and has primarily been focusing his work on UV-C based methods. He is passionate about the applying the latest microbiological technologies to the planetary protection discipline.
Country: United States of America
Company: Jet Propulsion Laboratory
Job Title: Research Scientist
Bio: Arman has been a research scientist with the Biotechnology and Planetary Protection group at JPL for the past 5 years with a background in microbiology and bioinformatics. His work encompasses all aspects of planetary protection including bacterial detection and enumeration using both traditional culture based techniques and molecular methods. Arman has experience in the development of microbial reduction modalities and has primarily been focusing his work on UV-C based methods. He is passionate about the applying the latest microbiological technologies to the planetary protection discipline.
Country: United States of America
Company: Jet Propulsion Laboratory
Job Title: Research Scientist