Towards a passive limitation of particle surface contamination in the Columbus module (ISS) during the MATISS experiment of the Proxima Mission.

Future long-duration human spaceflight calls for developments to limit biocontamination of the surface habitats. The MATISS experiment tests surface treatments in the ISS's atmosphere. Four sample holders were mounted with glass lamella with hydrophobic coatings, and exposed in the Columbus module for ~6 months. About 7800 particles were detected by tile scanning optical microscopy (×3 and ×30 magnification) indicating a relatively clean environment (a few particles per mm2), but leading to a significant coverage-rate (>2% in 20 years). Varied shapes were displayed in the coarse (50-1500 µm2) and fine (0.5-50 µm2) area fractions, consistent with scale dices (tissue or skin) and microbial cells, respectively. The 200-900 µm2 fraction of the coarse particles was systematically higher on FDTS and SiOCH than on Parylene, while the opposite was observed for the <10 µm2 fraction of the fine particles. This trend suggests two biocontamination sources and a surface deposition impacted by hydrophobic coatings.

Antimicrobial surfaces for use on inhabited space craft: A review.

Biodegradation of materials on crewed spacecraft can cause disruption, loss of function and lost crew time. Cleaning of surfaces is only partially effective due in accessibility and resource concerns. Commonly affected surfaces are hand-touch sites, waste disposal systems and liquid-handling systems, including condensing heat exchangers. The use of materials on and within such affected systems that reduce the attachment of and degradation by microbes, is an innovative solution to this problem. This review aims to examine both terrestrial and space-based experiments that have aimed to reduce microbial growth which are applicable to the unique conditions of crewed spacecraft. Traditional antimicrobial surfaces such as copper and silver, as well as nanoparticles, long-chain organic molecules and surface topographical features, as well as novel "smart" technologies are discussed. Future missions to cis-lunar and Martian destinations will depend on materials that retain their function and reliability for their success; thus, the use of antimicrobial and antifouling materials is a pivotal one.

Optical feedback interferometry for microscale-flow sensing study: numerical simulation and experimental validation.

Optical feedback interferometry (OFI) performance for microscale-flow sensing is studied theoretically and experimentally. A new numerical modeling approach for OFI flow meter spectrum reproduction is presented in this work to study the optical effect on the signal due to the micro-scale channel geometry. Two well-defined frequency peaks are found in the OFI spectrum, this phenomenon can be attributed to the reflection of the forward scattered light on the channel rear interface. The flow rate measurement shows good accuracy over a range of fluid velocities from 16.8 mm/s to 168 mm/s, thus providing a promising tool to study and to optimize the OFI microfluidic sensor system.