General Mars
  Implications of Life

  Definition of Life
  Martian Meteorite

Data Analysis
  Thin Section Analysis
  Isotope Analysis
  Gas Chromatograph Mass Spectrometer
  Infrared Spectroscopy
  Alpha-Proton X-Ray Spectrometer
  Detection of Carbon Complexes
  Labeled Release
  Gas Exchange
  Pyrolytic Release
  Stimulus Response Experiments

Scientific Research and Design
Data Analysis -- Alpha-Proton X-Ray Spectrometer

An Alpha-Proton X-Ray Spectrometer is able to determine elemental chemistry of Martian dust (above and sub-surface) and rocks for most elements except hydrogen. Spectroscopic Analysis will be a critical part of our mission to Mars. The instrument works by three types of interactions of alpha particles with matter: electron scattering of alpha particles by nuclei, alpha-proton nuclear reactions with certain light elements, and excitation of the atomic structures of atoms by alpha particles. This results in a spectrum of emissions of characteristic X-ray spectrum. 

Positive: Material identification - The mass spectrum of the unknown compound can be searched against computerized reference library of over 275,000 spectra for identification. A match with a known organic substance would identify a positive. The concentration of the various compounds in a sample can be quantified by establishing a standard curve of known concentrations of each material. 

Negative: As this experiment is primarily used for identification of samples, a negative would be any sample that showed no evidence of containing organic compounds.

False-Positive: Any unique markers could be confused. We would be unable to determine this significance of these until after further experiments.

mitCopyright © 2000 Massachusetts Institute of Technology
Comments and questions to Last updated: 10 December, 2000