koch-tataru solutions are global-in-time small data mild solutions to the 3d nse emanating from small data in $bmo^{-1}$. there have been several recent works in which the regularizing-decay rate estimates for koch-tataru solutions have been obtained. spatial analyticity of solutions then follows as a consequence. i will present a different approach in which the spatial analyticity is obtained directly together with explicit estimates on the time-evolution of the domain of analyticity. the regularizing-decay rate estimates will then follow at once.