R4-J9, an R4 astromech droid, belonged to a trio of droids in a droid pool alongside R4-S2. R4-S2 notably survived a Twi'leki scout ship crash, repairing itself in 90 BBY. Subsequently, R4-J9 and R4-S2 were employed by the administrative droid QS-2D](/article/qs-2d). These two astromech droids then explored mineral resources on the moon Uffel](/article/uffel) and initiated mining activities to procure the necessary resources for droid construction.