Rockets use two types of propellant; there are liquid fuel and solid fuel rockets. Liquid fuel rockets have separate tanks of volatile liquids, such as liquid hydrogen and liquid oxygen (called LOX). These are stored in large, heavily insulated tanks at extremely low temperatures until just before the time of launch, when they are piped into the waiting rocket. The advantage of such a rocket is that the fuel supply can be turned on or off by the opening or closing of a valve. The disadvantage is in the storing, transporting, and handling of extremely volatile and combustible liquids. Solid fuels have the advantage of easy storage, transportation, and handling. They have the disadvantage of once they are ignited they continue to burn until the fuel is all spent; there is no way of turning them off. Both types of fuel depend on delivering a sustained reaction rather than a sudden explosion. In the case of a jet engine and a rocket engine, the expanding gases are allowed to exit from one side of the combustion chamber but not from the opposite side, thereby creating an unequal internal pressure. The two are different in that the jet requires air while the rocket has a self-contained oxygen supply. Thus, a jet cannot function beyond the earth's atmosphere whereas a rocket can operate in a vacuum.
Military rockets are almost exclusively solid fuel rockets because they are much easier to store, transport, and use by troops in the field or at sea. Therefore a great deal of research was done in the early stages of WWII on the composition and design of solid propellants to be used in barrage rockets, air-to-air missiles, ground-to-air missiles such as bazookas, and air-to-ground missiles. The final product of this research was a hard, black, rubbery solid that burned rapidly and steadily when ignited by an electric spark. Various shapes were tried to produce the best uniformity of burning area over the life of the fuel rod. Cylinders of different cross-sectional configuration were tried, solid cylinders, hollow cylinders, star shaped cylinders, square shaped cylinders, and many variations of these were tried, but they all burned either too fast or too slow or unevenly due to a variation of burning area. There was one shape that seemed to best fit the specifications of constant burning area, and that was a cylinder with the cross section of a cross, called a cruciform.
Isn't it rather coincidental that rocket fuel in the shape of a cross propelled man into space on his way toward the stars, and that God chose a cross to make a way for man to escape the destruction of earth's final holocaust? Jesus could have bled and died in a number of ways, by the hands of an angry mob on a hill near Nazareth, or by the hands of the Pharisees in the temple, but God had planned long before Jesus was born that He be lifted up on a cross. So, "the way of the cross" is "the cruciform connection."
