Scott Perl | Searcharxiv

arXiv2026

Evaluation and Modeling of Pneumatic Percussive Drill for Martian Subsurface Access

Deep subsurface access on Mars could enable sampling of ancient lacustrine deposits, volatile-rich horizons, and other geologic targets beyond the reach of current shallow drilling systems. This study evaluates a wireline pneumatic rotary-percussive drill concept that uses compressed atmospheric CO2 as both the actuation and transport fluid. The architecture combines a pneumatically driven hammer, magnetic flapper-valve, and incremental bit-indexing mechanism in a compact bottom-hole assembly for low-power deployment. We develop a reduced-order model of the hammer and chamber dynamics that captures coupled pressure, flow, and impact behavior during each strike. The model is compared with benchtop percussion experiments and used to interpret hammer velocity, displacement, strike timing, and impact energy. A modified testbed is then used to drill Martian rock simulants spanning weaker sandstone and stronger Saddleback basalt cases, linking drilling response to operating pressure and material properties. The experiments show repeatable percussive impacts and mechanical specific energy values from 74 to 360 MJ/m3, with lower values in weaker simulant and higher values in stronger basalt. The results indicate that the system is most effective in a percussion-dominant mode with bit geometry matched to available impact energy. Together, the architecture study, validated model, and drilling experiments support the wireline pneumatic drill as a candidate for low-power deep drilling on Mars, while identifying remaining work in robustness, cuttings removal, and full-system integration.

physics.geo-ph↗

arXiv2022

Community Report from the Biosignatures Standards of Evidence Workshop

The search for life beyond the Earth is the overarching goal of the NASA Astrobiology Program, and it underpins the science of missions that explore the environments of Solar System planets and exoplanets. However, the detection of extraterrestrial life, in our Solar System and beyond, is sufficiently challenging that it is likely that multiple measurements and approaches, spanning disciplines and missions, will be needed to make a convincing claim. Life detection will therefore not be an instantaneous process, and it is unlikely to be unambiguous-yet it is a high-stakes scientific achievement that will garner an enormous amount of public interest. Current and upcoming research efforts and missions aimed at detecting past and extant life could be supported by a consensus framework to plan for, assess and discuss life detection claims (c.f. Green et al., 2021). Such a framework could help increase the robustness of biosignature detection and interpretation, and improve communication with the scientific community and the public. In response to this need, and the call to the community to develop a confidence scale for standards of evidence for biosignature detection (Green et al., 2021), a community-organized workshop was held on July 19-22, 2021. The meeting was designed in a fully virtual (flipped) format. Preparatory materials including readings, instructional videos and activities were made available prior to the workshop, allowing the workshop schedule to be fully dedicated to active community discussion and prompted writing sessions. To maximize global interaction, the discussion components of the workshop were held during business hours in three different time zones, Asia/Pacific, European and US, with daily information hand-off between group organizers.

astro-ph.IM↗