Report of the workshop for life detection in samples from Mars

Abstract

International audienceThe question of whether there is or was life on Mars has been one of the most pivotal since Schiaparellis' telescopic observations of the red planet. With the advent of the space age, this question can be addressed directly by exploring the surface of Mars and by bringing samples to Earth for analysis. The latter, however, is not free of problems. Life can be found virtually everywhere on Earth. Hence the potential for contaminating the Mars samples and compromising their scientific integrity is not negligible. Conversely, if life is present in samples from Mars, this may represent a potential source of extraterrestrial biological contamination for Earth. A range of measures and policies, collectively termed ‘planetary protection’, are employed to minimise risks and thereby prevent undesirable consequences for the terrestrial biosphere. This report documents discussions and conclusions from a workshop held in 2012, which followed a public conference focused on current capabilities for performing life-detection studies on Mars samples. The workshop focused on the evaluation of Mars samples that would maximise scientific productivity and inform decision making in the context of planetary protection. Workshop participants developed a strong consensus that the same measurements could be employed to effectively inform both science and planetary protection, when applied in the context of two competing hypotheses: 1) that there is no detectable life in the samples; or 2) that there is martian life in the samples. Participants then outlined a sequence for sample processing and defined analytical methods that would test these hypotheses. They also identified critical developments to enable the analysis of samples from Mars

Multiplication of microbes below 0.690 water activity: implications for terrestrial and extraterrestrial life

“…de Vera, R. V. Gough, J. E. Hallsworth, J. W. Head, V. J. Hipkin, T. L. Kieft, A. S. McEwen, M. T. Mellon, J. Mikucki, W. L. Nicholson, C. R. Omelon, R. Peterson, E. Roden, B. Sherwood Lollar, K. L. Tanaka, D. Viola and J. J. Wray, unpublished. Planetary‐protection policy, in relation to space missions, aims to protect those planets where spacecraft are landed, as well as Earth, from accidental contamination with non‐native life forms (Kminek et al ., 2010; 2014). Mars special regions have been defined according to the activities of the NASA Mars Exploration Program Analysis Group's (MEPAG)'s Special Regions‐Scientific Analysis Group 1 (SR‐SAG1) and the Committee on Space Research (COSPAR) which is part of the International Council for Science.…”

The potential science and engineering value of samples delivered to Earth by Mars sample return

“…; Kminek et al. ). Additionally, under the COSPAR policy, a program of life detection and biohazard testing and/or a proven sterilization process is an absolute precondition for the controlled distribution of any portion of the sample and would be required in order to perform some of the other analyses proposed in this document.…”

“…) and a workshop report about life detection in Martian samples was published in 2014 (Kminek et al. ). All investigations rely on several assumptions about the properties we presume to be common to all life.…”

“…Such updated approaches need to be integrated with preliminary scientific examination, as they are complementary and intrinsically related (Haltigin and Smith ; Kminek et al. ). In addition, the revisions should take into consideration terrestrial technological advances in the intervening period, particularly in the context of robotic handling (e.g., surgical equipment and microelectronics industries) and updated life detection instrumentation and technologies (e.g., ‐omics type approaches) (Johnson et al.…”

Planning Considerations Related to the Organic Contamination of Martian Samples and Implications for the Mars 2020 Rover

“…6). There are different ways of organizing the way various interpreters think about the data [e.g., the null hypothesis (see Kminek et al, 2014)], but regardless of how the hypotheses are structured, all would make use of the same analytic data from the samples. Once samples are available for Earth-based analysis, they would be analyzed for their organic contents to the maximum degree possible.…”