Thor IRBM System Operation
All of the Thor missiles deployed in Great Britain 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 electronically rolled back the missile shelter and then, using a powerful hydraulic launcher-erector, lifted the missile to an upright position. Once it was standing on the launch mount, the missile was fueled and fired. The entire launch sequence took about 15 minutes.
When the launch control officer pressed the firing button, the main engine ignited with a roar. It burned for almost 2l/2 minutes, boosting the missile to a speed of 14,400 feet per second. Ten minutes into its flight the missile reached an altitude of 280 miles, close to the apogee of its elliptical flight path. At that point the reentry vehicle separated from the fuselage and began its descent down toward the target. Total flight time from launch to impact: 18 minutes.