European Space Agency, Mars Exploration Group, Noordwijk, The Netherlands.
NASA Headquarters, Office of Planetary Protection, Washington, DC, USA.
Astrobiology. 2022 Jun;22(S1):S186-S216. doi: 10.1089/ast.2022.0017.
The Committee on Space Research (COSPAR) Sample Safety Assessment Framework (SSAF) has been developed by a COSPAR appointed Working Group. The objective of the sample safety assessment would be to evaluate whether samples returned from Mars could be harmful for Earth's systems ( environment, biosphere, geochemical cycles). During the Working Group's deliberations, it became clear that a comprehensive assessment to predict the effects of introducing life in new environments or ecologies is difficult and practically impossible, even for terrestrial life and certainly more so for unknown extraterrestrial life. To manage expectations, the scope of the SSAF was adjusted to evaluate only whether the presence of martian life can be excluded in samples returned from Mars. If the presence of martian life cannot be excluded, a Hold & Critical Review must be established to evaluate the risk management measures and decide on the next steps. The SSAF starts from a positive hypothesis (there is martian life in the samples), which is complementary to the null-hypothesis (there is no martian life in the samples) typically used for science. Testing the positive hypothesis includes four elements: (1) Bayesian statistics, (2) subsampling strategy, (3) test sequence, and (4) decision criteria. The test sequence capability covers self-replicating and non-self-replicating biology and biologically active molecules. Most of the investigations associated with the SSAF would need to be carried out within biological containment. The SSAF is described in sufficient detail to support planning activities for a Sample Receiving Facility (SRF) and for preparing science announcements, while at the same time acknowledging that further work is required before a detailed Sample Safety Assessment Protocol (SSAP) can be developed. The three major open issues to be addressed to optimize and implement the SSAF are (1) setting a value for the level of assurance to effectively exclude the presence of martian life in the samples, (2) carrying out an analogue test program, and (3) acquiring relevant contamination knowledge from all Mars Sample Return (MSR) flight and ground elements. Although the SSAF was developed specifically for assessing samples from Mars in the context of the currently planned NASA-ESA MSR Campaign, this framework and the basic safety approach are applicable to any other Mars sample return mission concept, with minor adjustments in the execution part related to the specific nature of the samples to be returned. The SSAF is also considered a sound basis for other COSPAR Planetary Protection Category V, restricted Earth return missions beyond Mars. It is anticipated that the SSAF will be subject to future review by the various MSR stakeholders.
空间研究委员会（COSPAR）样本安全评估框架（SSAF）是由 COSPAR 任命的工作组开发的。样本安全评估的目的是评估从火星返回的样本是否对地球系统（环境、生物圈、地球化学循环）有害。在工作组的审议过程中，很明显，全面评估引入新环境或生态系统中的生命的影响是困难的，甚至对于地球生命也是不可能的，对于未知的外星生命更是如此。为了管理预期，SSAF 的范围被调整为仅评估从火星返回的样本中是否可以排除火星生命的存在。如果不能排除火星生命的存在，必须建立一个保留和关键审查，以评估风险管理措施，并决定下一步行动。SSAF 从一个积极的假设（样本中有火星生命）开始，这与通常用于科学的零假设（样本中没有火星生命）互补。测试积极的假设包括四个要素：（1）贝叶斯统计，（2）抽样策略，（3）测试序列，和（4）决策标准。测试序列能力涵盖自我复制和非自我复制的生物学和生物活性分子。与 SSAF 相关的大多数调查都需要在生物遏制设施内进行。SSAF 被描述得足够详细，以支持样本接收设施（SRF）的规划活动，并为科学公告做准备，同时承认在制定详细的样本安全评估协议（SSAP）之前还需要进一步的工作。为了优化和实施 SSAF，需要解决三个主要的未决问题（1）为有效排除样本中火星生命的存在设定一个置信度水平，（2）开展模拟测试计划，（3）从所有火星样本返回（MSR）飞行和地面元素中获取相关污染知识。虽然 SSAF 是专门为在当前计划的 NASA-ESA MSR 活动的背景下评估来自火星的样本而开发的，但这个框架和基本的安全方法适用于任何其他火星样本返回任务概念，只需对与返回样本的具体性质相关的执行部分进行微小调整。SSAF 也被认为是其他 COSPAR 行星保护类别 V 的坚实基础，限制了火星以外的地球返回任务。预计 SSAF 将接受各种 MSR 利益相关者的未来审查。
