The journal Vacuum takes us from pure science towards engineering for Dec (vol. 242):
Wang, J. Zhang, R. Li, W. Study of sealing effect about the Shape Memory Alloy-based Knife-edge Seal System in extraterrestrial soil sample return mission 114731 .2025.114731
Collecting samples is no walk in the park. We must convince ourselves that the non-terrestrial material has not been contaminated by our terrestrial hands, microbes, air, etc. Nor should the precious sample somehow lose its ‘freshness’- here, loss of volatile components, altering the sample chemistry. The chief way we do this is by a well-sealed sample container- plastic bags and coolers for Antarctic meteorites (already well-exposed to the air), more rigorous shielding for truly extraterrestrial-sourced grains. Wang et al. detail that rigor: of note, the Hayabusa2 sample return chamber, and by extension other sampling systems like it.
The original Hayabusa sampled an S-type asteroid, not expected to be volatile-rich and capable of harboring microbes or their traces (its own, or Earth microbes). Then Hayabusa2 targeted a carbonaceous-chondrite asteroid, which we know (from carbonaceous-chondrite meteorites) to harbor water, organics, and other life-relevant material like sulfur and nitrogen. The JAXA managers then upgraded the Hayabusa sample capsule, among other improvements. Where the Hayabusa capsule was sealed with two O-rings (primary and backup), the Hayabusa2 design had a primary and backup knife edge bite into a soft metal gasket, ideally forming a hermetic seal. We now know, in hindsight, the seals were enough to stop most (heavy) organics, but the asteroid’s helium content still got diluted by contamination from Earth helium.
We are, as claimed by multiple people, in the age of sample return. Upcoming are the Tianwen sampling and return (from Kamo’oalewa), and the MMX observation and sampling of Phobos. And talk of a comet sample return hasn’t stopped- that concepts to this point have failed to reach the launch pad does not mean the concept itself is not valid and worthy.