jettisonable

/ˈdʒɛtɪsənəbəl/
adjective
  1. Capable of being thrown away or discarded, especially from a moving vehicle or vessel to lighten the load.
    • The fuel tanks on the spacecraft are jettisonable after launch to reduce weight.
    • The pilot checked the jettisonable external fuel pods before takeoff.
    • In an emergency, the cargo is jettisonable to keep the ship afloat.