AION: an atom interferometer observatory and network. Issue 5 (6th May 2020) - Badurina, L.; Bentine, E.; Blas, D.; Bongs, K.; Bortoletto, D.; Bowcock, T.; Bridges, K.; Bowden, W.; Buchmueller, O.; Burrage, C.; Coleman, J.; Elertas, G.; et al.