Tags: Weapon.
The W21 was an hydrogen bomb design for the US military. It would have used the physics package of the TX-21 bomb. The TX-21 was a weaponized version of the Shrimp device tested in the Bravo shot of Operation Castle. A TX-21C was tested as the Navajo shot Operation Redwing. The TX-21 was a scaled-down version of the Runt device (M-17 hydrogen bomb). Smaller in size and weight to the Mk-17 the Mk-21 was considered as a potential missile warhead.