Preliminary Planning for Mars Sample Return (MSR) Curation Activities in a Sample Receiving Facility (SRF)

Abstract

This paper was written by the MSR Science Planning Group 2 (MSPG2) working under a Terms of Reference from NASA and ESA.

Time-Sensitive Aspects of Mars Sample Return (MSR) Science

“…The differences between martian surface conditions and those in the pristine sample environment in curation labs on Earth, coupled with the stability fields of hydrated sulfates as a function of P, T, and RH, indicate that there could be problems with preserving hydrated sulfates long term in the curation environment, although the degree to which hydrated sulfates represent a time-sensitive analysis in a sample return facility (i.e., timescale of 2-3 years) requires additional knowledge about the kinetics of hydration and dehydration reactions. Knowing that sulfate phases will likely be out of equilibrium with the SRF isolator conditions (Tait et al, 2021) underscores the time-sensitive nature of analysis of these phases.…”

“…These goals encompass the investigation targets identified in Table 4 that significantly degrade within window B (i.e., 1-10 months) or that may degrade within window B on the basis of estimated uncertainties due to sample lithification, cementation, etc. The goals also include characterization of the sample headspace gas which may not be inherently time-sensitive across window B but has been deemed so because results of these analyses inform the curation workflow (see also MSPG Science in Containment Report and Tait et al, 2021).…”

“…The headspace of this secondary container should be subject to periodic compositional or isotopic monitoring of gaseous species that may have escaped the sample tube if a seal has been breached. This recommendation can be achieved, for example, by placement within a Sample Tube Isolation Chamber (STIC), as discussed by Tait et al (2021).…”

Planning Implications Related to Sterilization-Sensitive Science Investigations Associated with Mars Sample Return (MSR)

“…It does not discuss the relative efficacies of different sterilization procedures; neither does it make any judgment on which sterilization procedure could or should be used on returned samples. The present state of knowledge and planning regarding sterilization, including the relationship between initial sample characterization workflow and SSAP, is briefly addressed elsewhere in the collection of papers of which this report is a part (e.g., for SSAP, see overview in Carrier et al, 2021, and details in Kminek et al, 2021; for initial sample characterization and curation workflow, see Tait et al, 2021). The COSPAR SSAP Working Group (Kminek et al, 2021) worked simultaneously with MSPG2 but independently from it.…”

“…Homogeneous samples will be easy to sub-divide; heterogenous (inhomogeneous) samples will require extra attention. Some information about the homogeneity of the samples will be available from the robotic instrumental analyses made during sampling on Mars; the most useful information on the returned samples themselves will be acquired during the thorough initial sample characterization and preliminary examination during curation (Tait et al, 2021). Individual subsamples may be processed differently, depending on the specific requirements of each proposed analytical measurement.…”