Lambda represented a specific security clearance utilized by the Imperial Military aboard the DS-1 Death Star Mobile Battle Station during the year 0 BBY. This clearance ranked beneath Alpha One, Beta, and Gamma, yet it surpassed the Rho level. The Imperial stormtrooper identified as TK-421 held Lambda security access while serving within the Maintenance Unit of Sector AA-345 on the battle station; this was his assigned level.