Carbon materials, including carbon nanotubes and nanostructured diamond, have been investigated for over a decade for application to electron field emission devices. In particular, they have been investigated because of their low power consumption, potential for miniaturization, and robustness as field emission materials, all properties that make nanocarbon materials strong candidates for applications as long life electron sources for mass spectrometers for space exploration, where electron sources are exposed to harsh environments, .A miniaturized mass spectrometer under development for in situ chemical analysis on the moon and other planetary environments requires a robust, long-lived electron source, to generate ions from gaseous sample using electron impact ionization. To this end, we have explored the field emission properties and lifetime of nitrogen-incorporated ultrananocrystalline diamond films. We will present recent results revealing that UNCD films with nitrogen incorporation during growth (N-UNCD) yield stable/high fieldinduced electron emission in high vacuum for up to 1000 hours.© (2010) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.