Laser technology and its application to numerous problems of relevance to nuclear physics, nuclear medicine, radiography and imaging have developed tremendously within the last several decades. Intense, high-power lasers capable of delivering ultra-short pulses of radiation (on the order of femtoseconds, or one billion billionths of a millisecond) allow examination of the fundamental properties of high-intensity laser-matter interactions. More recently, interest has developed in using such lasers for ion acceleration. However, the numerous mechanisms of ion acceleration depend greatly on laser and target parameters that have not been extensively studied. European scientists initiated the LASER-ION Accelerato project to investigate such mechanisms and provide practical recommendations for optimising ion yield given laser intensities of interest. Significant improvements to the ratio between laser pulse intensity to noise intensity (temporal pulse contrast) enabled experiments to study new acceleration mechanisms such as radiation pressure acceleration (RPA). Scientists also studied so-called mass-limited targets (MLTs), whose limited sizes lead to additional interactions of electrons with the laser pulse, thus enhancing ion energy. LASER-ION Accelerato yielded advanced understanding of ion acceleration mechanisms with ultra-short pulse lasers. Project insights could have important impact on nuclear physics, imaging and table-top radio-nucleotide production for medical applications.