Deployment
Thor was deployed to the UK starting in August 1958, operated by 20 squadrons of RAF Bomber Command. The first active unit was No. 77 Squadron RAF at RAF Feltwell in 1958, with the remaining units becoming active in 1959. All were deactivated by September 1963.
All 60 of the Thor missiles deployed in the UK were based at above-ground launch sites. The missiles were stored horizontally on transporter-erector trailers and covered by a retractable missile shelter. To fire the weapon, the crew used an electric motor to roll back the missile shelter (essentially a long shed mounted on steel rails), then used a powerful hydraulic launcher-erector to lift the missile to an upright position for launch. Once it was standing on the launch mount, the missile was fueled and could be fired. The entire launch sequence (from starting to roll back the missile shelter through to ignition of the rocket engine and lift-off) took approximately 15 minutes. Main engine burn time was almost 2.5 minutes, boosting the missile to a speed of 14,400 ft/s (4,400 m/s). Ten minutes into its flight the missile reached an altitude of 280 miles (450 km), close to the apogee of its elliptical flight path. At that point the reentry vehicle separated from the missile fuselage and began its descent toward the target. Total flight time from launch to target impact was approximately 18 minutes.
The Thor was initially deployed with a very blunt conical G.E. Mk 2 'heat sink' re-entry vehicle. They were later converted to the slender G.E. Mk 3 ablative RV. Both RVs contained a W-49 thermonuclear warhead with an explosive yield of 1.44 megatons.
Read more about this topic: PGM-17 Thor