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In Situ Real-Time Monitoring for Aseptic Drilling: Lessons Learned from the Atacama Rover Astrobiology Drilling Studies Contamination Control Strategy and Implementation and Application to the Icebreaker Mars Life Detection Mission.
Bonaccorsi, Rosalba; Glass, Brian; Moreno-Paz, Mercedes; García-Villadangos, Miriam; Warren-Rhodes, Kimberley; Parro, Victor; Manchado, Juan Manuel; Wilhelm, Mary Beth; McKay, Christopher P.
Affiliation
  • Bonaccorsi R; SETI Institute, Mountain View, California, USA.
  • Glass B; NASA Ames Research Center, Moffett Field, California, USA.
  • Moreno-Paz M; NASA Ames Research Center, Moffett Field, California, USA.
  • García-Villadangos M; Department of Molecular Evolution, Centro de Astrobiología (INTA-CSIC), Madrid, Spain.
  • Warren-Rhodes K; Department of Molecular Evolution, Centro de Astrobiología (INTA-CSIC), Madrid, Spain.
  • Parro V; SETI Institute, Mountain View, California, USA.
  • Manchado JM; NASA Ames Research Center, Moffett Field, California, USA.
  • Wilhelm MB; Department of Molecular Evolution, Centro de Astrobiología (INTA-CSIC), Madrid, Spain.
  • McKay CP; Department of Molecular Evolution, Centro de Astrobiología (INTA-CSIC), Madrid, Spain.
Astrobiology ; 23(12): 1303-1336, 2023 12.
Article in En | MEDLINE | ID: mdl-38133823
ABSTRACT
In 2019, the Atacama Rover Astrobiology Drilling Studies (ARADS) project field-tested an autonomous rover-mounted robotic drill prototype for a 6-Sol life detection mission to Mars (Icebreaker). ARADS drilled Mars-like materials in the Atacama Desert (Chile), one of the most life-diminished regions on Earth, where mitigating contamination transfer into life-detection instruments becomes critical. Our Contamination Control Strategy and Implementation (CCSI) for the Sample Handling and Transfer System (SHTS) hardware (drill, scoop and funnels) included out-of-simulation protocol testing (out-of-sim) for hardware decontamination and verification during the 6-Sol simulation (in-sim). The most effective five-step decontamination combined safer-to-use sterilants (3%_hydrogen-peroxide-activated 5%_sodium-hypochlorite), and in situ real-time verification by adenosine triphosphate (ATP) and Signs of Life Detector (SOLID) Fluorescence Immunoassay for characterization hardware bioburden and airborne contaminants. The 20- to 40-min protocol enabled a 4-log bioburden reduction down to <0.1 fmoles ATP detection limit (funnels and drill) to 0.2-0.7 fmoles (scoop) of total ATP. The (post-cleaning) hardware background was 0.3 to 1-2 attomoles ATP/cm2 (cleanliness benchmark background values) equivalent to ca. 1-10 colony forming unit (CFU)/cm2. Further, 60-100% of the in-sim hardware background was ≤3-4 bacterial cells/cm2, the threshold limit for Class <7 aseptic operations. Across the six Sols, the flux of airborne contaminants to the drill sites was ∼5 and ∼22 amoles ATP/(cm2·day), accounting for an unexpectedly high Fluorescence Intensity (FI) signal (FI ∼6000) against aquatic cyanobacteria, but negligible anthropogenic contribution. The SOLID immunoassay also detected microorganisms from multiple habitats across the Atacama Desert (anoxic, alkaline/acidic microenvironments in halite fields, playas, and alluvial fans) in both airborne and post-cleaning hardware background. Finally, the hardware ATP background was 40-250 times lower than the ATP in cores. Similarly, the FI peaks (FImax) against the microbial taxa and molecular biomarkers detected in the post-cleaned hardware (FI ∼1500-1600) were 5-10 times lower than biomarkers in drilled sediments, excluding significant interference with putative biomarker found in cores. Similar protocols enable the acquisition of contamination-free materials for ultra-sensitive instruments analysis and the integrity of scientific results. Their application can augment our scientific knowledge of the distribution of cryptic life on Mars-like grounds and support life-detection robotic and human-operated missions to Mars.
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Full text: 1 Collection: 01-internacional Database: MEDLINE Main subject: Robotics / Cyanobacteria / Mars Limits: Humans Language: En Journal: Astrobiology Journal subject: BIOLOGIA Year: 2023 Document type: Article Affiliation country: United States

Full text: 1 Collection: 01-internacional Database: MEDLINE Main subject: Robotics / Cyanobacteria / Mars Limits: Humans Language: En Journal: Astrobiology Journal subject: BIOLOGIA Year: 2023 Document type: Article Affiliation country: United States