Rocket

                                       Rocket

                                       

• A rocket is a missile, spacecraft, aircraft or other vehicle that obtains thrust from a rocket engine. Rocket engine exhaust is formed entirely from propellants carried within the rocket before use.^[Rocket engines work by action and reaction. Rocket engines push rockets forward simply by throwing their exhaust backwards extremely fast.
• While comparatively inefficient for low speed use, rockets are relatively lightweight and powerful, capable of generating large accelerations and of attaining extremely high speeds with reasonable efficiency. Rockets are not reliant on the atmosphere and work very well in space.
• Rockets for military and recreational uses date back to at least 13th century China. Significant scientific, interplanetary and industrial use did not occur until the 20th century, when rocketry was the enabling technology of the Space Age, including setting foot on the moon. Rockets are now used for fireworks,weaponry, ejection seats, launch vehicles for artificial satellites,human spaceflight, and space exploration.
• Chemical rockets are the most common type of rocket and they typically create their exhaust by the combustion of rocket propellant. Chemical rockets store a large amount of energy in an easily released form, and can be very dangerous. However, careful design, testing, construction and use minimizes risks

History of the rocket

                                           

• The availability of black powder (gunpowder) to propel projectiles was a precursor to experiments as weapons such as bombs, cannon, incendiary fire arrows and rocket-propelled fire arrows.^{[nb 1][nb 2]} The discovery of gunpowder was probably the product of centuries of alchemical experimentation in whichTaoist alchemists were trying to create an elixir of immortality that would allow the person ingesting it to become physically immortal.
  Exactly when the first flights of rockets occurred is contested. A problem is that Chinese fire arrows can be either arrows with explosives attached, or arrows propelled by gunpowder. There were reports of fire arrows and 'iron pots' that could be heard for 5 leagues (25 km, or 15 miles) when they exploded, causing devastation for a radius of 600 meters (2,000 feet), apparently due to shrapnel.A common claim is that the first recorded use of a rocket in battle was by the Chinese in 1232 against the Mongol hordes at Kai Feng Fu.However, the lowering of iron pots there may have been a way for a besieged army to blow up invaders.^{[nb 3]} A scholarly reference occurs in the Ko Chieh Ching Yuan (The Mirror of Research), states that in 998 AD a man named Tang Fu invented a fire arrow of a new kind having an iron head.
  Less controversially, one of the earliest devices recorded that used internal-combustion rocket propulsion, was the 'ground-rat,' a type of firework recorded in 1264 as having frightened the Empress-Mother Kung Sheng at a feast held in her honor by her son the Emperor Lizong.
  Subsequently, one of the earliest texts to mention the use of rockets was the Huolongjing, written by the Chinese artillery officer Jiao Yu in the mid-14th century. This text also mentioned the use of the first known multistage rocket, the 'fire-dragon issuing from the water' (huo long chu shui), used mostly by the Chinese navy