People: Astrobiology Graduate Students

David J. Smith
Biology

I have always been captivated with astrobiology and the prospect of discovering life beyond Earth. I am passionate about spaceflight and eager to be involved in the new era of scientific exploration on the Moon and Mars. As a NASA graduate co-op, I combine my PhD research with practical work experience at Kennedy Space Center (typically one quarter per year). I came to the University of Washington from Princeton University, where I studied Ecological & Evolutionary Biology and wrote my undergraduate senior thesis on the survivability of spacecraft-associated bacteria under simulated Martian surface conditions.

The Graduate Certificate Program in Astrobiology was the central factor in my decision to attend UW, where I knew it would be possible (and encouraged!) to bridge the gaps between scientific disciplines while conducting my PhD research. Based in the Biology Department, my research interest relates to the aerobiology of Earth's upper atmosphere. To sample this environment I have worked with NASA high-altitude aircraft and mountaintop observatories in the Pacific Northwest. I am trying to understand the diversity, survival, and distribution of microorganisms injected into the stratosphere; a challenging environment characterized by high irradiation, low temperature and pressure, and extreme desiccation. This field of study calls upon a number of specialties, including microbiology, atmospheric science, and geochemistry.

Beyond my aerobiology interests, I have participated in several exciting research rotations during my early years in the Astrobiology Program at UW. First in February 2009, and then again in November 2009, I accompanied my advisor Peter Ward to the Antarctic Peninsula where we conducted field geology from a remote camp to provide temporal resolution to late Cretaceous rocks using paleomagnetics and biostratigraphy. Recently, I returned to NASA KSC to evaluate the efficacy of antimicrobial materials in microgravity environments; a task which culminated with Zero G flight experiments in August 2009.

Publications

Smith, D. J., Schuerger, A. C., Davidson, M. M., Pacala, S. W., Bakermans, C. and Onstott, T. C. 2009. Survivability of Psychrobacter cryohalolentis K5 under simulated martian surface conditions. Astrobiology 9(2): 221-228.

Smith, D. J., Griffin, D. W. and Schuerger, A. C. 2009. Stratospheric microbiology at 20 km over the Pacific Ocean. Aerobiologia (in-press).