Biotechnology and Planetary Protection Group, California Institute of Technology, Jet Propulsion Laboratory, Pasadena, California, USA.
Department of Chemistry and Biochemistry, California State University, Northridge, California, USA.
Astrobiology. 2023 Aug;23(8):825-834. doi: 10.1089/ast.2022.0046. Epub 2023 Jul 3.
The Mars 2020 Flight System comprises a Cruise Stage; Aeroshell; Entry, Descent, and Landing system; Perseverance rover; and the Ingenuity helicopter. The Perseverance rover was successfully delivered to Jezero Crater on February 18, 2021. Among its science objectives, Perseverance is meant to search for rocks that are capable of preserving chemical traces of ancient life, if it existed, and to core and cache rock and regolith samples. The Perseverance rover is gathering samples for potential return to Earth as part of a Mars Sample Return campaign. Thus, controlling the presence of Earth-sourced biological contamination is important to protect the integrity of the scientific results as well as to comply with international treaty and NASA requirements governing Planetary Protection prior to launch. An unprecedented campaign of sampling and environmental monitoring occurred, which resulted in over 16,000 biological samples collected throughout spacecraft assembly. Engineering design, microbial reduction measures, monitoring, and process controls enabled the mission to limit the total spore bioburden to 3.73 × 10 spores, which provided 25.4% margin against the required limit. Furthermore, the total spore bioburden of all landed hardware was 3.86 × 10, which provided 87% margin against the required limit. This manuscript outlines the Planetary Protection implementation approach and verification methodologies applied to the Mars 2020 flight system and its surrounding environments.
火星 2020 飞行系统包括巡航级；气壳；进入、下降和着陆系统；毅力号火星车；以及机智号直升机。毅力号火星车于 2021 年 2 月 18 日成功运抵杰泽罗陨石坑。其科学目标之一是寻找能够保存古代生命化学痕迹的岩石，如果存在的话，还将对岩石和风化层样本进行取芯和缓存。毅力号火星车正在收集样本，以备作为火星样本返回活动的一部分送回地球。因此，控制源自地球的生物污染的存在对于保护科学结果的完整性以及遵守国际条约和 NASA 关于发射前行星保护的要求非常重要。进行了一次前所未有的采样和环境监测活动，在整个航天器组装过程中收集了超过 16000 个生物样本。工程设计、微生物减少措施、监测和过程控制使该任务能够将总孢子生物负荷限制在 3.73×10 个孢子以内，比所需限值高出 25.4%。此外，所有着陆硬件的总孢子生物负荷为 3.86×10，比所需限值高出 87%。本文概述了应用于火星 2020 飞行系统及其周围环境的行星保护实施方法和验证方法。
