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Microscopy, Electrochemistry, and Conductivity Analyzer (MECA)

NSSDCA ID: 2007-034A-03

Mission Name: Phoenix Mars Lander
Principal Investigator:Dr. Michael H. Hecht


The Microscopy, Electrochemistry, and Conductivity Analyzer (MECA) is designed to perform detailed studies of the martian soil, using a suite of instruments. MECA consists of a wet chemistry laboratory, optical and atomic force microscopes, and a thermal and electrical conductivity probe.

The wet chemistry laboratory's objective is to determine the soil pH, conductivity, redox potential, and abundance of magnesium and sodium cations and chloride, bromide, and sulfate anions. It comprises four beakers with buit-in sensors which contain a calibrated, warmed soaking solution. A soil sample is delivered to a beaker by the robotic arm. The sample is soaked, stirred, and measurements are made throughout the day. The sample is then allowed to freeze overnight and thaw the next morning. Then four crucibles containing solid reagents are added to test for carbonates and sulfates. Each beaker can only be used once.

The optical and atomic force microscopes are used to examine the detailed structure of soil samples delivered by the robotic arm, including searching for clays and hydrous minerals. The optical microscope has a resolution of 4 microns per pixel and a field of view of roughly 1 x 2 mm. Illumination is provided by various combinations of red, green, blue, and ultraviolet LEDs. The atomic force microscope has a resolution of 10 nanometers. Each sample is first delivered to a wheel containing 69 different substrates to distiguish between different adhesion mechanisms. The wheel rotates under the microscopes so different sample-substrate combinations can be viewed.

The thermal and electrical conductivity probe is attached to the robotic arm. It is a small plastic head containing small spikes which are inserted by the robotic arm into the end of an excavated trench. The probe will measure the temperature, thermal properties of the soil, and electrical conductivity.

Alternate Names

  • MECA
  • PhoenixMarsLander/MECA
  • urn:nasa:pds:context:instrument:meca_afm.phx
  • urn:nasa:pds:context:instrument:meca_elec.phx
  • urn:nasa:pds:context:instrument:meca_tecp.phx
  • urn:nasa:pds:context:instrument:meca_wcl.phx
  • urn:nasa:pds:context:instrument:om.phx


  • Planetary Science: Geology and Geophysics

Additional Information

Questions and comments about this experiment can be directed to: Dr. David R. Williams



NameRoleOriginal AffiliationE-mail
Dr. Michael H. HechtLead InvestigatorNASA Jet Propulsion

Selected References

  • Zent, A. P., et al., The Thermal and Electrical Conductivity Probe (TECP) for Phoenix, J. Geophys. Res., 114, E00A27, doi:10.1029/2007JE003052, 2008.
  • Kounaves, S. P., et al., The MECA Wet Chemistry Laboratory on the 2007 Phoenix Mars Scout Lander, J. Geophys. Res., 114, E00A19, doi:10.1029/2008JE003084, 2008.
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