Real-Time Quantification of Size-Resolved Bioaerosols and Inert Particles in Spacecraft Assembly Facilities at the NASA Jet Propulsion Laboratory.

Abstract Responsible space exploration is a cornerstone of planetary protection, particularly at sites in the Solar System with a high potential for the existence of extant life. To limit bioburden, spacecraft assembly occurs in cleanroom facilities. Cleanroom levels are established through air particulate counters that can assess particle size distribution and concentration but cannot detect bioaerosols. Additionally, these devices do not detect in real-time, which poses a risk to critical flight hardware assemblies or even mission timelines. A first-of-its-kind study was conducted to simultaneously detect bioaerosols, inert particles, and their size distribution in real-time in operational spacecraft assembly cleanrooms at NASA's Jet Propulsion Laboratory in Pasadena, CA, USA, using the BioVigilant IMD-A® 350 (Azbil Corporation, Tucson, AZ, USA). The IMD-350A continuously sampled during operations and no-operation 6 h intervals in two facilities per cleanroom class: ISO 6, ISO 7, and ISO 8. A positive correlation was established between human presence in the cleanroom and elevated bioaerosol counts. Smaller particles of sizes 0.5 and 1 µm constituted an average ∼91% of the total bioaerosols detected in At Work intervals across all ISO classes observed. The results of this study were used to establish bioburden particulate thresholds for the most stringent JPL cleanrooms used in the assembly of the Sample Caching System for the Mars 2020 Perseverance rover.

Planetary Protection Implementation of the InSight Mission Launch Vehicle and Associated Ground Support Hardware.

The InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) Mars mission launched from Vandenberg Air Force Base on an Atlas V 401 rocket on May 5, 2018. Prior to launch, the InSight spacecraft, associated launch vehicle hardware, and ground support equipment were required to satisfy Planetary Protection requirements to comply with international treaty obligations and demonstrate compliance with National Aeronautics and Space Administration (NASA) levied bioburden requirements. InSight was the first bioburden-controlled mission to launch from Vandenberg Air Force Base and required mission-unique policies and procedures to ensure Planetary Protection requirements were satisfied. All the launch vehicle hardware and associated ground support equipment with direct contact or line of sight to flight hardware were required to demonstrate a bioburden density of less than 1,000 spores/m2. Additionally, the environmental control system air ducts were required to demonstrate more stringent bioburden limits on internal duct surfaces (<100 spore/m2) and on air passing through the ducts (88 colony-forming units/m3). Although conservative approaches were used with the data analysis and launch recontamination analysis, InSight, the launch vehicle hardware, and ground support equipment were able to demonstrate compliance with the Planetary Protection requirements needed for launch approval. Here we detail the biological practices implemented on the launch vehicle hardware and ground support equipment that resulted in biologically clean hardware and the satisfaction of Planetary Protection.