Each missile was tipped with a one-megaton nuclear warhead, jointly controlled by the Royal Air Force and the United States Air Force under the so-called dual-key arrangements. RAF Hemswell was also the headquarters for the No. 5 (Lincolnshire) Missile Dispersal Sites located at RAF Bardney, RAF Caistor, RAF Coleby Grange and RAF Ludford Magna. The Cuban Missile Crisis brought the entire UK based Thor missile force to maximum strategic alert and readiness for a ten-day period during October and November 1962.