Loss of calcium bone mass during exposure to microgravity is a serious concern for the space station crew due to the probability of prolonged exposures. Rather than use radioisotopes for in-flight metabolic studies, stable calcium isotopes will be employed as tracers for convenient, noninvasive determinations of calcium absorption and related metabolic indicators. Saliva will be the body fluid to be used in this method. Analytical methods will be developed using chemical separations and thermal ionization mass spectrometry, initially, leading to the utilization of a highly efficient calcium isotopic analysis system based on auto-ionization-mediated laser photo-ionization. An examination of the calcium dynamics for pre-flight, in-flight, and post-flight periods may provide insight into the mechanisms of bone demineralization. A pilot study will be conducted parallel with ongoing tracer experiments, and the results will be directly compared with those acquired under standard conditions. The technical objectives are to develop a method to separate calcium from saliva; demonstrate the ability to atomize, ionize, a nd determine isotope ratios of calcium separated from the saliva matrix; conduct ground-based calcium dynamics experiments using calcium stable isotope tracers as part of an ongoing NASA bone demineralization study for SLS-1 and SLS-2 flights; and assess the results to determine the analytical and biomedical viability of saliva for calcium absorption measurements.Commercial applications of this research are expected to evolve from a potentially large market for clinical diagnostic measurements of calcium absorption and for instrumentation, materials (kits), and processes related to the technology.saliva, calcium, stable isotopes, absorption, mass spectrometry, boneSTATUS: Phase I Only
