Overview

Rockets have been used as early as A.D. 1232, when the Chinese employed them as unguided missiles to repel the Mongol besiegers of the city of Pein-King (Peiping). Also, in the fifteenth century, Korea developed the sinkijon ^[*] (or Sin-Gi-Jeon) rocket. Manufactured from the early fifteenth to mid-sixteenth century, the sinkijon was actively deployed in the northern frontiers, playing a pivotal role in fending off invasions on numerous occasions. Once out of the rocket launcher, the fire-arrows were set to detonate automatically near the target area. Also, the high-powered firearm was utilized in the southern provinces to thwart the Japanese marauders. The main body of the sinkijon's rocket launcher was five to six meters long, the largest of its kind at that time ^[**]. A sinkijon was capable of firing as many as one hundred fire-arrows or explosive grenades. The fire-arrow contained a device equipped with gunpowder and shrapnel, timed to explode near the target. The introduction of gunpowder made possible the use of cannon and muskets that could fire projectiles great distances and with high velocities. It was desirable in so far as the study of cannon fire is desirable to learn the paths of these projectiles, their range, the heights they could reach, and the effect of muzzle velocity. Several years later, the sinkijon went through another significant upgrade, which enabled it to hurl a fire-arrow made up of small warheads and programmed to detonate and shower multiple explosions around the enemy.