Considerations for the Mars Sample Return Containment Facility
Abstract
The Mars Sample Return (MSR) campaign represents the first Category V Restricted Earth Return mission since Apollo 14, the last sample return with that classification. As with Apollo and all future restricted sample return missions, collecting samples from planetary bodies considered by scientific opinion to be "of significant interest to the process of chemical evolution and/or the origin of life" by NASA's Office of Planetary Protection requires the implementation of an array of safety precautions. In order to isolate the restricted samples from Earth's biosphere, a BSL-4 containment facility may be utilized until the samples are deemed safe for release. Traditionally high containment facilities are designed to protect scientist and the community from exposure to known hazard(s). However, properly handling, examining, and curating Martian samples adds two extra complexities for said containment facility: 1) the samples may contain "unknown unknown" hazards, which complicates the hazard assessment and 2) the samples need to be protected from terrestrial contamination so Planetary Protection (PP) and Science investigations are not impeded. This combined effort requires the integration of both negative and positive pressure environments to meet the needs of PP and contamination control (CC), respectively. In order to help meet the PP and CC requirements, double walled isolators that integrate both positive and negative pressure regimes can be utilized. However, to our knowledge, there is no facility in existence with both the necessary bio-safety containment level (e.g. BSL-4) and clean room standards (e.g. ISO Class 5 or better) (hereafter BSL-4+). Therefore, less apparent is how the BSL-4+ containment facility recommendation will be implemented. As with all new astromaterial collections, there are two main facility considerations when designing and building new curation laboratories: whether to renovate an existing space or build new. In the case of a new build, both traditional and modular construction are being evaluated. While an array of considerations are important to evaluate (e.g. structural constraints, ability to meet CC/PP requirements, cost effectiveness, and fair use), our current focus is on structural constraints and the ability to meet CC/PP requirements. As with all new builds, one of the major benefits is that it can be highly customized to meet all requirements. This customization could be critical in order to meet the array of CC, PP, and science requirements. However, one of the major criticisms of building a BSL-4+ facility for restricted earth sample return missions, is the long term usefulness. Currently, the only restricted sample return mission planned is MSR, if the biohazard assessment can be completed in less than two years, how financially responsible is it to have a permanent facility? Alternatively, if the samples are never deemed safe for distribution this could be a more permanent home. Or, if Mars samples are released, this facility could enable the return of other restricted samples (e.g. Europa or Enceladus). Furthermore, if deemed sufficient, the use of more modular construction methods could defer the costs while also allowing for more flexibility over time. Alternatively, the program could renovate space within an existing containment facility. The use of any existing BSL-4 containment facility would likely require extensive renovations in order to meet CC standards. During this process, the facility would need to be decontaminated and shut down for a significant amount of time; possibly making sharing space with other laboratories impossible. Furthermore, when evaluating an existing facility for possible renovation, there are a number of different features that need to be considered. The first, and perhaps most basic, is to ensure the facility has the proper clearances for installing the proper cleanrooms and adequately sized entry/egress points for moving in large equipment (e.g. DWI's, analytical instruments). Furthermore, in many of these facilities, the structure is built around larger pieces of equipment (e.g. autoclaves). Therefore, if DWIs are to be utilized, they will need to be designed small enough or in enough pieces, to pass through the specialized doors. The integration of CC and PP requirements could also be tenuous if renovating existing space. It is uncertain whether new inert gas lines can be installed which may be required given the range of possible microenvironments proposed and the limited pristinity recirculation filters offer relative to single-pass inert gas could be problematic. Some types of contamination (e.g. silicon) can be very difficult to remove and represent a risk to sample pristinity. Finally, it is uncertain whether any existing facility is able to meet both bio-safety containment and clean room standards, and whether such standards can be sustained long-term given the probable limited space available for updates and regular maintenance. Facility planning and implementation need to start as soon as possible given the proposed MSR Campaign timeline. However, the numerous unknowns related to MSR do not allow for specific guidelines for a containment facility. It will be important to minimize costs related to either new construction or adapting an existing facility (provided the concerns above are addressed) while maximizing the credibility of the sample analyses. Reusing existing BSL-4 laboratory space is theoretically possible since it is likely that at least initial CC requirements can be met. However, there seems to be some scientific consensus that a new fully-integrated facility is the best option. Nevertheless, a final evaluation can only be made once PP, CC, and science requirements are defined.
- Publication:
-
43rd COSPAR Scientific Assembly. Held 28 January - 4 February
- Pub Date:
- January 2021
- Bibcode:
- 2021cosp...43E.417H