Project Emily

Thor Practice Launches

Once the three Thor missiles of each squadron were declared operational, the crews settled down to the routine of maintenance and training exercises that was required to keep the missiles at 15 minutes readiness.
The continual countdown exercises but without a launch led to Thor Squadrons being known as 'Penguin Squadrons' - All flap and no fly.

Technicians carrying out routine maintenance on a Thor missile inside its shelter
Image © IWM

A Launch Control Officer remembers:
"Life was routine shift-work practising launch countdowns, checking of the missile systems and sitting in the Launch Control Trailer hoping that war wouldn't break out."

From L to R: The RAF Launch Control Officer (LCO), the US Authentication Officer (AO), the Assistant RAF LCO and the key for the missiles at RAF Driffield
Image © IWM

Once the order to launch had been received, the RAF LCO turned his key in the panel where he sat.
Once the key was turned, the launch was an automated process and consisted of five phases.

Phase 1:
An automatic electronic check of all systems followed by the retraction of the missile shelter.

The missile was raised to the vertical and electric motors automatically unscrewed three bolts holding the missile to the launch mount.
At this point a missile could remain vertical for an extended period of time.

Phase 3:
Slowly at first, the two fuels were loaded into the missile (liquid oxygen and the RP-1 fuel stored at opposite ends of the emplacement).
The target data was checked by the long range electrotheodilite (a sophisticated system that ensured the rocket was aimed correctly).
At this point, the missile technician would make a speedy exit from the launch area.
Fuelled, the missile could remain in this state for a maximum of two hours.

Phase 4:
Final electronic checks, the fuel topped up to the exact amount.
During this phase the US AO turned his key to authorise the launch.

Phase 5:
The missile launches - a Thor launch would destroy the emplacement.
When the warhead separated from the main body of the missile it would be travelling at Mach 10.

A Thor is raised to the upright and fuel (liquid oxygen) is loaded
Image © IWM

It is important to note that during practice launches a dummy warhead was fitted (the original would be moved to the Classifed Storage Building).
Liquid oxygen could be loaded and removed from the missile without leaving any residue. However, if RP-1 was loaded but there was no launch then the missile had to be returned to the US for specialist cleaning. To prevent this situation arising, the RP-1 by-passed the missile and simply moved from one storage tank to another.
Additionally, never being fully fuelled (liquid oxygen and RP-1) meant there was no chance of an accidental launch.

There are numerous stories of RAF technicians being able to 'hot-wire' the missile launch controls to by-pass the security keys.
A screwdriver was sometimes used to activate the US key when the AO was unavailable.
Other tales tell of arming the warhead by pressing a wet finger against the US keyhole and activation initiated by the LCO tapping his desk with a pencil...!!

This simulated image shows the LCO at Caistor tapping his pencil on the control desk
After the above incident, the US lock was hastily replaced.