Complementary to parallel open access and analysis preservation initiatives, ATLAS is taking steps to ensure that the data taken by the experiment during Run-1 remain accessible and available for future analysis by the collaboration. An evaluation of what is required to achieve this is underway, examining the ATLAS data production chain to establish the effort required and potential problems. Several alternatives are explored, but the favoured solution is to bring the Run 1 data and software in line with the equivalent to that which will be used for Run 2. This will result in a coherent ATLAS dataset for the data already taken and that to come in the future.