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SN 1987A is the great supernova (SN) of the HST era. An unbroken string of observations is the essential tool for detecting change and establishing a uniform legacy archive. Recent imaging has shown dramatic changes in the ejecta and the interaction with the circumstellar material. After a steady increase in flux comma the inner circumstellar ring reached a maximum in 2009 and is now fading rapidly as it is destroyed by shocks. At the same time comma diffuse emission and new spots outside the inner ring are becoming visible comma gradually revealing previously unseen material that extends toward the outer rings. Monitoring this emission is required to understand the formation of the rings and the mass-loss history of the progenitor star. In addition comma the expanding innermost ejecta reveal asymmetries and mixing in the explosion. As the ejecta expand comma X-rays from the inner ring penetrate into the metal-rich core comma which results in a brightening in the optical band. We request imaging in narrow and broad filters over the next three cycles to follow these developments. Annual observations are needed to monitor the rapid evolution of the shocks. Imaging in additional filters in one of the cycles will provide flux measurements crucial to estimating the energy budget of the ejecta comma that comma perhaps comma will begin to reveal the elusive compact object. The HST observations have a unique blend of photometric fidelity and angular resolution that make them the indispensable partner to ongoing X-ray comma sub-mm ALMA comma and ground-based optical-NIR observations. They are also an important complement to the JWST GTO observations in 2022.