Roots Of Rocketry

Historians believe that armies began hurling combustible weapons toward one another as early as 1,000 B.C. At the time, fire pots were used to set fires. Fire pots were simply pots containing flammable materials like naphtha that were ignited and hurled by various mechanical devices. The concept was simple, yet effective as fire pots were able to be easily deployed and could set fires over fairly large areas. Still, these were not rockets in the traditional sense.

Although the exact date remains a mystery, it is believed that the reaction principle, the physical law of rocket motion, was first demonstrated about 360 B.C. by a Greek named Archytas. Far from demonstrating the reaction principle in a weapon, Archytas simply filled a hollow clay pigeon with water. He then suspended the clay pigeon by string over a fire. The heating of the water produced steam, and the clay pigeon could move under its own power as steam escaped through strategically placed holes. Archytas could hardly have imagined that the same basic principle would one day carry men to the Moon.

About three hundred years after the pigeon, another Greek, Hero of Alexandria, invented a similar rocket-like device called an aeolipile. It, too, used steam as a propulsive gas. Hero mounted a sphere on top of a water kettle. A fire below the kettle turned the water into steam, and the gas traveled through pipes to the sphere. Two L-shaped tubes on opposite sides of the sphere allowed the gas to escape, and in doing so gave a thrust to the sphere that caused it to rotate.

Black Powder :

By about 200 B.C. it is believed that the Chinese mastered the mixing and use of gunpowder. Known as black powder until the invention of guns, gunpowder would prove to be the primary ingredient of the first true ballistic rockets. The Chinese created the first gunpowder through the traditional mixing of charcoal, saltpeter and sulphur. While rocketry was still a long way away, the explosive nature of gunpowder was well demonstrated by the Chinese through the loading and detonation of firecrackers.

Solid propellants of the composite type contain separate fuel (or reducer, chemically) and oxidizer (in a separate compound) intimately mixed. While generally not considered as composite, black powder was in fact the oldest composite propellant. Before 1940 black powder, in common use, was nearly synonymous with the words `rocket motor'.

Black powder technically should not be called gunpowder because its use in rockets preceded that in guns. The ingredients are charcoal, sulphur, and saltpeter (potassium nitrate). These three ingredients were known in China for many centuries, however, before they were combined into black powder. Charcoal was known from the earliest times, and sulphur and saltpeter at least since the sixth century AD, and probably as far back as the first century BC That the saltpeter is definitely of Chinese origin is indicated by the names given to this material by the Arabs, who called it "Chinese snow", and the Persians, who called it "salt from China".

By 1045, just twenty-one years before William the Conqueror invaded Saxon England, the Chinese were well acquainted with black powder. The Wu-ching Tsung-yao (Complete Compendium of Military Classics) published that year, contained many references to the subject.

In black powder, saltpeter (potassium nitrate- KNO 3 ) is the oxidizer, while sulphur (S), and charcoal (mainly carbon- C) are the fuel. But, depending on the percentage of each ingredient, sulphur may also act as an oxidizer for potassium in the reaction: 2KNO 3 + S + 3C = K 2 S + N 2 + 3CO 2 .

Some early black powder formulae:

Saltpeter + sulphur + acacia seeds.

1 chin 14 ounces of sulphur, together with 2 1/2 chin of saltpeter, 5 ounces of charcoal, 2 1/2 ounces of pitch, and 2 1/2 ounces of dried varnish are powdered and mixed. Next, 2 ounces of dried plant material, 5 ounces of tung oil, and 2 1/2 ounces of wax are also mixed to form a paste. Then these ingredients are all mixed together, and slowly stirred, The mixture is then wrapped in a parcel with five layers of paper, which is fastened with hempen thread, and some melted pitch and wax and is put on the surface.

Black powder had a very low specific impulse. About 1280 AD, Arab military men, referring to the propulsive ability of black powder, suggested improvements over the simple Chinese skyrocket. One interesting innovation was what might be best described as an air squid or traveling land mine; it could scurry across land in the manner of a squid through water.

Chinese Rockets :

By about 600 A.D. it is believed that the Chinese had adapted the use of gunpowder from firecrackers to fireworks. Certain writings of the era indicate that the Chinese used small explosive charges to send other explosive charges into the air for entertainment.

By 900 A.D., the Chinese began experimenting with the gunpowder-filled tubes. At some point, they attached bamboo tubes to arrows and launched them with bows. Soon they discovered that these gunpowder tubes could launch themselves just by the power produced from the escaping gas. The true rocket was born.

The date reporting the first use of true rockets was in 1232. At this time, the Chinese and the Mongols were at war with each other. During the battle of Kai-Keng, the Chinese repelled the Mongol invaders by a barrage of "arrows of flying fire." These fire-arrows were a simple form of a solid-propellant rocket. A tube, capped at one end, contained gunpowder. The other end was left open and the tube was attached to a long stick. When the powder was ignited, the rapid burning of the powder produced fire, smoke, and gas that escaped out the open end and produced a thrust. The stick acted as a simple guidance system that kept the rocket headed in one general direction as it flew through the air.

The fire arrows carried flammable materials or sometimes poison-coated heads. In a form more closely resembling modern rockets, the gunpowder tube was lengthened to the tip of the arrow and given a pointed nose, eliminating the need for a traditional arrowhead. Once it was discovered that the fire arrows flew a straight path even after their feathers were burned up by the gunpowder exhaust, the feathers were completely removed. The resulting fire arrow was quite similar in appearance to fireworks used today. The Chinese typically launched these fire arrows in salvos from arrays of cylinders or boxes which could hold as many as 1,000 fire arrows each. The fire arrows propelled by gunpowder may have had a range of up to 1,000 feet. It is not clear how effective these arrows of flying fire were as weapons of destruction, but their psychological effects on the Mongols must have been formidable.

According to Chinese folk tale, a man named Wan-Hoo made the first attempt to carry a man in a rocket propelled vehicle in around 1500. He reportedly took two large horizontal stakes and tied a seat between them. Under the primitive device were placed 47 rockets set to be lit all at the same time. When the rockets were ignited, they burned erratically and could not provide effective thrust to move the contraption. Wan-Hoo is said to have burned to death in the resulting fire.

Rockets in Europe :

By the end of the 13th century, armies of Japan, Java, Korea and India are believed to have acquired sufficient knowledge of gunpowder and fire arrows to begin using them against the Mongols. Use of the weapons quickly spread throughout Asia and Eastern Europe. Military writings of al-Hasan al-Rammah indicate that in 1285, Arabs began using gunpowder propelled fire arrows in combat. It is believed that gunpowder propelled fire arrows were subsequently used by Arabs against French troops of Louis IX during the 7th Crusade.

In 1379, an Italian named Muratori used the word "rochetta" when he described types of gunpowder propelled fire arrows used in medieval times. This is believed to be the first use of the word later translated in English as "rocket". The French are reported to have made extensive use of war rockets throughout the 15th century. In 1429, French troops led by Joan of Arc reportedly used rockets in their successful defense of the city of Orleans. The French also are reported to have used rockets in their sieges of Pont-Andemer in 1449, Bordeaux in 1452 and Gand in 1453. German field artillery colonel Christoph Friedrich is reported to have begun experimenting with war rockets weighing 55 to 120 pounds as early as 1668. In 1680, Peter the Great established the first rocket factory in Russia. Originally located in Moscow, the rocket factory provided the Russian Army with battlefield illumination rockets.

British Congreve Rockets :

By 1804, Colonel (later Sir) William Congreve had begun studying and refining captured Indian rockets at the Royal Laboratory, Woolwich Arsenal in Kent. His first product was an elongated, larger version of Indian rockets specifically designed to be launched from ships for the purpose of setting fires on an enemy shoreline. A variety of rockets, which quickly became known as Congreve rockets after their designer, were introduced weighing 18, 24, 32, 42, 100 or 300 pounds. The rocket most widely used in battle weighed 32 pounds, with a gunpowder charge housed in a casing 3 feet, 6 inches long by 4 inches wide. Each 32-pound rocket was typically mounted on a stick measuring 15 feet long by 1.5 inches wide. Thus, they became known as stick rockets. Stick rockets could be produced inexpensively and in large numbers. Many stick rockets employed a conical, metal warhead that embedded itself in its target before oozing a slow-burning incendiary mixture.

On September 13 and 14, 1814 a 25-hour barrage of Congreve rockets was fired from the British ship Erebus against Fort McHenry in Baltimore. The Erebus carried about 20 Congreve rocket batteries consisting of a box housing multiple metal firing tubes. Each of the rockets fired against Fort McHenry weighed about 30 pounds, and carried an incendiary charge. Although a number of American ships were destroyed by Congreve rockets during the War of 1812, just four deaths and minimal damage was reported at Fort McHenry during the siege. However, the battle was witnessed by a young lawyer named Francis Scott Key, who mentioned the Congreve "rockets' red glare" in his song "The Star Spangled Banner". The song later became the U.S. National Anthem, paying tribute to the tenacity of the American forces under siege.

One of the first peaceful uses of a Congreve-type rocket was introduced by Englishman Henry Trengrouse who fastening a light cord to a small rocket, then launching the rocket over a ship in distress. Sailors then hauled in the cord, fastened a more sturdy rope to it and could either pull themselves or be pulled to safety. Under certain rescue conditions, a similar practice is still in use today.

Hale Rockets :

By the middle of the 19th century, improved British rockets eclipsed long-lived Congreve rockets. Separate studies conducted in France and the United States suggested that rockets would be more accurate if they were spun, like the way a bullet is spun after it leaves a gun barrel. An Englishman named William Hale was the first rocket designer to take advantage of this principle. He adopted a combination of tail fins and secondary nozzles through which exhaust could pass. Hale rockets became the first spin-stabilized rockets, and quickly became standard equipment for both the British and United States armies.

Although Hale rockets were more accurate than Congreve rockets, they could not travel as far, and typically had a maximum range of 2,000 yards. A version with a 2.25-inch diameter weighed 6 pounds, while a version with a 3.25-inch diameter weighed 16 pounds. The United States made their first use of Hale rockets during the Mexican War of 1846-1848. Since the United States and Great Britain were allies by this time, Hale rockets were made readily available to U.S. troops. Thus, Hale rockets were the first rockets used by United States armed forces in battle.

The use of war rockets diminished as the latter half of the 19th century dawned, primarily due to significant advances in conventional artillery. Perhaps prophetically, the British adapted a large number of military rockets as fireworks to light up the Thames River during the Peace of Aix-la-Chapelle celebration of 1849.

First Multi-Stage Rocket :

The year 1855 saw the introduction of the first two-stage rocket, and it was developed for peaceful purposes. The ship rescue line concept pioneered by Henry Trengrouse was improved to increase the range of the rockets and allow for the transport of heavier cord. What became known as the Boxer rocket was developed by British Lt. Colonel E.M. Boxer at the Royal Laboratory. The rocket weighed just six pounds, but incorporated two gunpowder charges separated by a small charge of quick-burning powder.

As the first gunpowder charge "stage" burned itself out in an upward direction, it ignited the quick-burning powder charge and fell away. The quick-burning powder charge then ignited the second gunpowder charge "stage" which continued on toward its target. Boxer rockets were able to carry a durable half-inch hemp line a distance of about 1,000 feet. The rockets were used in rescue line applications until shortly after World War I.

In the latter half of the 19th century, rockets were also used in an interesting, if now considered inhumane, manner. Whaling rockets, also known as whaling harpoons, had a barbed pointed head carrying an explosive charge designed to detonate after entering the whale. A line was spliced to the rocket to aid in recovering the whale. Whaling rockets are perhaps most worthy of interest because they were launched from small hand-held tubes resembling the modern bazooka.

Civil War Rockets :

By the start of the Civil War in 1860, military rockets had all but disappeared. Rockets declined in importance due to the deadly accuracy of conventional artillery, most notably weapons with rifled barrels and breech loading. However, both sides in the Civil War remembered how well rockets served armed forces during the Mexican War two decades earlier. But, it was quickly discovered that Hale, and even Congreve, rockets that had been stored for long periods of time were rendered useless because their gunpowder charges failed to remain properly bonded to their casings.

This forced both sides to develop new rockets if rockets were to be used at all. The resulting rockets were considered primitive, even by the standards of the day, due to their inaccuracy and unreliability. But, a variety of rockets were used during the Civil War by both sides. On July 3, 1862 Confederate forces under the command of Jeb Stuart fired rockets at Union troops during the Battle of Harrison's Landing. Colonel James T. Kirk of the 10th Pennsylvania Reserves later wrote that one of his men was wounded by a projectile carried on a rocket fired from "a sort of gun carriage". Rocket batteries of this type were most often used by Confederate forces in Texas during campaigns in 1863 and 1864. These rockets and their launchers were first manufactured in Galveston, and later in Houston. The New York Rocket Battalion was the first Union force to be issued rockets. The group was organized by British officer Major Thomas W. Lion and was made up of 160 men. Rockets employed ranged in size from 12 to 20 inches long by 2 to 3 inches wide.

The rockets could be launched from light carriages carrying four wrought iron tubes, each of which was about 8 feet long. They could also be launched from 3.25-inch diameter guiding rods bound together in an open framework, or from individual 3-inch diameter sheet-iron tubes. Each rocket was primarily designed to deliver flammable compounds, but could carry musket balls placed in a hollow shell and exploded by a timed fuse. Although the New York Battalion rockets could fly a remarkable maximum distance of 3 miles, they were extremely erratic and were never used in combat.

Interest in war rockets continued to decline sharply following the Civil War, again due to advances in the pinpoint accuracy and increased range of conventional artillery. Rockets did, however, continue to be used for years to come in signaling and rescue applications.

Topical Questions :

How does black powder work and why did it lead to the beginning of rocket technology?

How were rockets used in early warfare? How were they effective and ineffective?

What were some of the early technological improvements to rockets that improved flight and distance?