1,- 1Space Research and Planetary Sciences, Physics Institute, University of Bern, Bern, Switzerland (rico.fausch@unibe.ch)
- 2Southwest Research Institute, Boulder, USA
- 3Lockheed Martin Space, Littleton, USA
- 4Lunar Scholar Services LLC, Aurora, USA
- 5Western Carolina University, Cullowhee, USA
- 6Brown University, Providence, USA
- 7The University of Manchester, Manchester, UK
- 8Colgate University, Hamilton, USA
The DIMPLE (Dating an Irregular Mare Patch with a Lunar Explorer) payload, selected under NASA’s PRISM program, will determine the age and chemical composition of rocks at Ina on the Moon. This objective will be achieved through in situ Rb–Sr isochron analysis performed by the Chemistry, Organics, and Dating EXperiment (CODEX) aboard a Commercial Lunar Payload Services (CLPS) lander. A critical subsystem of CODEX is a compact time-of-flight mass spectrometer designed for high mass resolution, high sensitivity, and long-term stability under lunar conditions. Its dual-mode concept maximizes science return, as (i) a 266 nm UV ablation laser provides spatially resolved bulk element geochemistry, and (ii) after the ablation plume expands, additional lasers resonantly ionize Rb and Sr in sequence, enabling precise isotope ratio measurements for geochronology. We present the status of the engineering development unit (EDU) and the roadmap to a flight-qualified instrument. The EDU incorporates a flight-like ion-optical subsystem that has been numerically modeled, built, and functionally tested. Initial tests confirm that the mass spectrometer meets the required mass resolution and sensitivity for both geochemical analysis and isotope dating. Ongoing EDU raster experiments demonstrate high accuracy and operational stability over repeated runs. When combined with proven sample-handling and imaging subsystems, this performance positions DIMPLE to deliver the first radiometric age for an irregular mare patch. By distinguishing between a young (~30 Ma) and an ancient (>3 Ga) origin for Ina, DIMPLE could refine lunar crater-count chronologies and constrain how long internal heat sources can sustain late-stage volcanism. The demonstrated analytical capability of CODEX establishes a foundation for precise planetary geochronology within the stringent mass, volume, and power constraints characteristic of small lunar payloads.
How to cite: Fausch, R., Aebi, A., Anderson, F. S., Bierhaus, E. B., Braden, S. E., Fagan, A. L., Head, J. W., Joy, K. H., Levine, J., Osterman, S., Pernet-Fisher, J. F., Tartèse, R., Wurz, P., and Yant, M.: Advancing Lunar Volcanism Studies: Status of the CODEX/DIMPLE Mass Spectrometer for Geochemical and Geochronological Measurements, EPSC-DPS Joint Meeting 2025, Helsinki, Finland, 7–12 Sep 2025, EPSC-DPS2025-1007, https://doi.org/10.5194/epsc-dps2025-1007, 2025.
