In-situ calibration methods for specialized penetrometers

In-situ calibration methods are essential for enhancing the reliability of specialized penetrometers used in extraterrestrial environments , where traditional Earth-based references are inapplicable. This study introduces a novel approach to in situ calibration using a robotic arm with an integrated scoop and imager to create reference surfaces. The Sample Acquisition, Morphology Filtering, and Probing of Lunar Regolith (SAMPLR) payload is used as a case study to illustrate the proposed methods. By generating low and high-density reference surfaces and employing photogrammetry for volumetric modeling, calibration models are developed to estimate relative density. Experimental results demonstrate the effectiveness of and penetration curve fit parameters in providing quantitative insights, with showing higher accuracy in estimating relative density. This work underscores the importance of localized calibration methods for penetrometer deployment in extraterrestrial environments, offering a framework for improved geotechnical analysis and operational success in future lunar and planetary missions.