When objects are deleted, they are permanently removed from DSpace. So, DSpace doesn't have an "undo" option for deletion. That said, you can restore objects individually if you do regular backups using AIP Backup & Restore. The AIP backup process allows
you to restore a single Community/Collection or Item via it's Archival Information Package (AIP):
https://wiki.lyrasis.org/display/DSDOC7x/AIP+Backup+and+Restore That said, it
requires exporting AIPs out of DSpace and storing them somewhere in case they are necessary for restoration.