How do thrust reversers work and what types are used?

Thrust reversers redirect exhaust flow forward to provide braking force on landing. Types include: Cascade/target systems (deflector doors block exhaust, cascades redirect flow outward and forward, used on high-bypass turbofans), Clamshell reversers (two halves close to redirect core flow, older designs), and Bucket/target reversers (buckets swing into exhaust path, common on older low-bypass engines). Deployed thrust is typically 40-50% of forward thrust. Design considerations: Actuation reliability, No re-ingestion of hot gas, Structural loads on nacelle, and Deploy time (<2 seconds). Modern cascades use composite construction. FADEC prevents in-flight deployment and manages asymmetric deployment.