CheminX: a next generation XRD/XRF for Mars exploration

CheMinX is a next generation of in-situ X-Ray Diffraction and X-Ray Fluorescence (XRD/XRF) instrument suitable for a range of planetary surface exploration including Discovery class missions and MER class rovers. The instrument is designed to provide quantitative mineralogy and elemental chemistry from drilled rocks and scooped soils on Mars, the Moon, Venus, or other rocky planetary bodies. 

Possible implementation of the CheMinX instrument, visible inside a MER sized rover (as modeled ~2.0x1.0x1.0 m, 120-150 kg). A powder collection and delivery system, such as a powder drill mounted on the arm of the rover, provides rock and soil samples to the instrument for mineralogical analysis.

CheMinX is based on similar principles as MSL-CheMin [add link to CheMin page], but benefits from a decade of advancements in geometry design and subsystem miniaturization. CheMinX addresses critical improvements in technology compared to CheMin:

  • a much improved XRD resolution using a dual CCD (Charge Couple Device) geometry, 
  • improved XRF performance by use of an SDD (Silicon Drift Detector) in back scattered geometry, 
  • a miniaturized Sample Handling System (SHS) allowing a much reduced volume.

Substantial reductions in mass, volume, and power relative to MSL-CheMin are now possible for planetary XRD/XRF instruments while achieving improved resolution and 10X reduction in data collection time.

CheMinX preliminary design. The instrument offers higher XRD and XRF performance in a package 1/3 the volume of CheMin on MSL. Dimensions 29 x 19 x 16.2 cm3.
Sample handling subsystem for the vibrated sample method based on single-use cells in a cartridge dispenser system. This sampling subsystem is being developed as part of a NASA PICASSO19 grant awarded to P. Sarrazin.

Sample Collection and Delivery

CheMinX requires the collection and delivery of powdered rock materials or soils. The development of simplified Sample Acquisition and Delivery Systems (SA/DS) is critical for the deployment of XRD instruments on smaller rovers. Such systems are being developed for deployment on MER-class rovers [Sarrazin et al, 2019]. As part of a NASA PICASSO19 grant awarded to P. Sarrazin,  simpler sample processing and delivery systems, including a micro-sampling drill designed for low power and load requirements are being fabricated and tested, and will demonstrate CheMinX with powdering drills and arm prototypes developed at Honeybee Robotics.

As a result of an anomaly of the drill feed mechanism on MSL, drill powders are now directly delivered to the CheMin instrument without sieving, by positioned the drill over the CheMin inlet and rotating the drill bit backwards. As-received drill powders are sufficiently fine to produce high-quality XRD patterns, demonstrating that a complex sample sieving and portioning system is not necessary for sample delivery to CheMinX on future martian rovers.

Honeybee Robotic’s Rasp tool on Phoenix robotic. The potential of a RASP tool will be evaluated as part of a trade study.
Possible implementation of a compact powder collection system [Zacny et al. 2013].

Primary partners in this research

  • NASA Ames Research Center (USA, CA)
  • SETI Institute (USA, CA)
  • Honeybee Robotics Spacecraft Mechanisms Corporation (USA, CA)
  • Baja Technology LLC (USA, AZ)
  • Battel Engineering (USA, AZ)
  • Teledyne e2v (UK)
  • RÖNTGEN-TECHNIK DR. WARRIKHOFF KG (Germany)

References

  • Sarrazin, P., Bristow, T. F., Blake, D. F., et al. (2019). “CheMinX: A Next Generation XRD/XRF for Mars Exploration.” LPI, abstract 2236.
  • Zacny, K., Paulsen, G., Chu, P., Hedlund, M., Spring, J., Osborne, L., … & Indyk, S. (2013). Axel rover NanoDrill and PowderDrill: Acquisition of cores, regolith and powder from steep walls. In 2013 IEEE Aerospace Conference (pp. 1-11). IEEE, Big Sky, Montana, March 2-9.