The future of UCNA: towards a sub-0.4\% measurement of the neutron beta decay asymmetry using ultracold neutrons

The UCNA experiment uses trapped ultracold neutrons (UCN) to measure the neutron beta decay asymmetry ``$A$''. Since publication of a proof-of-principle result in 2009, a series of improvements have increased the statistical and systematic sensitivity of the experiment, from an initial 4\% determination of $A$ to the 1.4\% result published in 2010 and the soon-to-be-published $\sim$0.7\% measurement. This talk describes plans for pushing the UCNA experiment towards the limits of its sensitivity (below 0.4\%), including higher precision polarimetry and energy calibrations, thinner windows to decrease backscattering and monte carlo corrections, and improvements in UCN production and transport.