Retcon article(covers information that was retroactively changed)
ADR looping was a mission that could be performed in a region of space between sectors 184/02 and 185/38 and near the Ficus sector.
In 2120, the SS Seattle was launched from Earth for a mission of ADR looping. (TNG: "Up The Long Ladder", okudagram)
In the remastered version of "Up The Long Ladder", a diplomatic mission to SR-47 replaced ADR looping.