Dr. Patricia Craig
Areas of research that I find most interesting involve the geochemical evolution of planetary surfaces. My current work focuses on the formation and alteration of clay minerals on Mars.
In collaboration with researchers in the ARES Lab at NASA Johnson Space Center, I design and conduct experiments that investigate the stability of clay minerals under a variety of conditions. This data helps us better constrain the conditions at the time of formation and subsequent alteration of these minerals, allowing us to reconstruct the geologic and aqueous history of the planet. The data generated also aids in interpreting data collected by orbiters and rovers on the mineralogy and chemistry of the surface.
I am also a collaborator on the Chemistry and Mineralogy (CheMin) instrument on the Mars Science Lab Curiosity rover. CheMin is the first X-ray diffractometer to be sent to and operate on another planet and it has been sending us valuable information on the mineralogy of Gale Crater, Mars. As part of the team, I prepare command sequences for the instrument, monitor its health on a regular basis, and help in analyzing and interpreting the data it sends back to Earth.
Additionally, I’ve begun a study that seeks to identify areas on Mars that were/are most conducive to the existence of life. Working with biologists at the University of Arkansas, our experiments have shown that methane-producing microbes, called methanongens, can grow and survive on certain clay minerals that have been identified on Mars. If methanogens are in fact still surviving on Mars, they could be responsible for the methane recently observed in the martian atmosphere.
I am also a Co-I on a study with researchers at the University of Arkansas and NASA Goddard Space Flight Center to experimentally determine the origin of the radar-bright anomalies in the venusian highlands. The prevailing theory that we’re testing is that the high pressure and temperature of the atmosphere causes it to react heavily with the surface. The result is the precipitation of highly radar-reflective minerals that are stable only at higher altitudes (i.e., lower temperature and pressure), similar to a “snow line” on Earth, except the “snow” on Venus likely consists of heavy metal compounds including mercury, bismuth, and tellurium.