is the ability to observe, take out a portion and preserve a precious return-sample without being exposed to the atmosphere and other contaminants. The Luna Soviet missions samples are studied and stored at the Vernadsky Institute of Geochemistry and Analytical Chemistry at the Russian Academy of Sciences. Restricted materials Return-samples obtained from a Category V body, must be curated at facilities rated Biosafety level-4 (BSL-4). Because the existing BSL-4 facilities in the world do not have the complex requirements to ensure the preservation and protection of Earth and the sample simultaneously, there are currently at least two proposals to build a BSL-4 facility dedicated to curation of restricted (potentially biohazard) extraterrestrial materials. The first is the European Sample Curation Facility (ESCF), proposed to be built in Vienna, would curate non-restricted samples as well as BSL-4 biocontainment of restricted material obtained from Category V bodies such as Mars, Europa, Enceladus, etc. The other proposal is by NASA and is tentatively known as the Mars Sample-Return Receiving Facility (MSRRF). At least three different designs were submitted in 2009. If funded, this American facility would be expected to take 7 to 10 years from design to completion, and an additional two years is recommended for the staff to become proficient and accustomed to the facilities. NASA is also assessing a 2017 proposal to build a mobile and modular BSL-4 facility to secure a sample return capsule at the landing site to conduct preliminary biohazard analyses. After completion of biohazard testing, decisions could be made to sterilize the sample or transport all or portions to a permanent quarantine storage facility anywhere in the world. The systems of such facilities must be able to contain unknown biohazards, as the sizes of any putative alien microorganisms or infectious agents are unknown. Ideally it should filter particles of 0.01 μm or larger, and release of a particle 0.05 μm or larger is unacceptable under any circumstance. The reason for this extremely small size limit of 0.01 μm is for consideration of gene transfer agents (GTAs) which are virus-like particles that are produced by some microorganisms that package random segments of DNA capable of horizontal gene transfer. These randomly incorporate segments of the host genome and can transfer them to other evolutionarily distant hosts, and do that without killing the new host. In this way many archaea and bacteria can swap DNA with each other. This raises the