Department for Internal Medicine, Section of Infectious Diseases and Tropical Medicine, Medical University of Graz, Graz, Austria.
BioTechMed-Graz, Graz, Austria.
Microbiome. 2017 Oct 25;5(1):143. doi: 10.1186/s40168-017-0358-3.
The ExoMars 2016 mission, consisting of the Trace Gas Orbiter and the Schiaparelli lander, was launched on March 14 2016 from Baikonur, Kazakhstan and reached its destination in October 2016. The Schiaparelli lander was subject to strict requirements for microbial cleanliness according to the obligatory planetary protection policy. To reach the required cleanliness, the ExoMars 2016 flight hardware was assembled in a newly built, biocontrolled cleanroom complex at Thales Alenia Space in Turin, Italy. In this study, we performed microbiological surveys of the cleanroom facilities and the spacecraft hardware before and during the assembly, integration and testing (AIT) activities.
Besides the European Space Agency (ESA) standard bioburden assay, that served as a proxy for the microbiological contamination in general, we performed various alternative cultivation assays and utilised molecular techniques, including quantitative PCR and next generation sequencing, to assess the absolute and relative abundance and broadest diversity of microorganisms and their signatures in the cleanroom and on the spacecraft hardware.
Our results show that the bioburden, detected microbial contamination and microbial diversity decreased continuously after the cleanroom was decontaminated with more effective cleaning agents and during the ongoing AIT. The studied cleanrooms and change room were occupied by very distinct microbial communities: Overall, the change room harboured a higher number and diversity of microorganisms, including Propionibacterium, which was found to be significantly increased in the change room. In particular, the so called alternative cultivation assays proved important in detecting a broader cultivable diversity than covered by the standard bioburden assay and thus completed the picture on the cleanroom microbiota.
During the whole project, the bioburden stayed at acceptable level and did not raise any concern for the ExoMars 2016 mission. The cleanroom complex at Thales Alenia Space in Turin is an excellent example of how efficient microbiological control is performed.
2016 年 3 月 14 日，“ExoMars 2016”任务从哈萨克斯坦拜科努尔发射升空，由“痕量气体轨道器”和“夏帕瑞丽着陆器”组成，于 2016 年 10 月抵达目的地。根据强制性的行星保护政策，“夏帕瑞丽着陆器”必须满足严格的微生物清洁度要求。为了达到所需的清洁度，“ExoMars 2016”飞行硬件在意大利都灵的泰雷兹阿莱尼亚航天公司新建的生物控制洁净室综合体中进行组装。在这项研究中，我们在组装、集成和测试 (AIT) 活动之前和期间，对洁净室设施和航天器硬件进行了微生物调查。
除了作为一般微生物污染代理的欧洲航天局 (ESA) 标准生物负荷测定法外，我们还进行了各种替代培养测定法，并利用分子技术，包括定量 PCR 和下一代测序，来评估洁净室和航天器硬件上微生物的绝对和相对丰度以及最广泛的多样性及其特征。
我们的结果表明，在洁净室用更有效的清洁剂进行消毒以及在持续的 AIT 过程中，生物负荷、检测到的微生物污染和微生物多样性不断下降。研究中的洁净室和更衣室被非常不同的微生物群落占据：总体而言，更衣室容纳了更多和更多样化的微生物，包括丙酸杆菌，它在更衣室中被发现明显增加。特别是，所谓的替代培养测定法在检测比标准生物负荷测定法涵盖的更广泛的可培养多样性方面证明是重要的，从而完成了洁净室微生物组的图片。
在整个项目期间，生物负荷保持在可接受的水平，没有给“ExoMars 2016”任务带来任何担忧。泰雷兹阿莱尼亚航天公司在都灵的洁净室综合体是高效微生物控制的一个极好范例。
