Inspired by the work of James Burke
Today we think of rockets as one of mankind’s latest and most advanced creations. Indeed, the Space Shuttle may well rank as the most complicated machine ever made. But far from being the latest development in powered vehicles, rockets were the first, and they are in principle about the simplest powered vehicle imaginable. So simple they’re easily understood by any school kid tasked with blowing up a birthday party balloon.
Left, the balloon rocket. Air pushes in all directions represent by force arrows called vectors. But if air can escape from one end, the opposite vector pushes the balloon in the other. Its a simple principle, no surprise it’s been around for a long time. What is surprising is that long before Teflon coated pans or the microchip were touted as spinoffs from the space program, it was those early rockets that helped fuel the development of revolutionary new technology that lays at the heart of modern civilization to this day.
No one knows for sure who invented it, but the consensus is that sometime between 800 and 900 AD, Chinese alchemists searching for the elixir of life stumbled on the formula. It became known as black-powder. And we know one of the earliest reported uses for black-powder was for rockets.
By the mid 13th century tales of the wondrous substance reached the ears of western nobility and the super secret formula work its way into the hands of local alchemists. It didn’t take warlords and feudal masters from the Middle East to England long to realize that if the precious powder could be ignited safely in a rigid tube, it might propel a heavy, red-hot projectile father than the slings and catapults of the day.
Left, the basic cannon showing the barrel (1), the cannon ball (2), black-powder propellant (3), and the fuse (4). Despite the simplicity of the design, it took generations to develop large, reliable, one-piece metal barrels that could hold together under repeated use.
Metal working was already a surprisingly mature industry by the time black-powder appeared on the scene, thanks to the endless demand for sharper, more durable swords and lighter, stronger armor. But it took a century or two of trial and error with various types of metal alloys and barrel designs that could handle the firing stress, many of which undoubtedly failed catastrophically killing anyone nearby, before relatively reliable cannons were widely available. And, as if that terror weapon wasn’t radical enough, a great deal of work was done perfecting a hand-held miniature version so that individual combatants could shoot smaller holes in one another.
By five hundred years ago most of the legions of archers, the quaint battle-axes, and exquisite suits of armor began slipping quietly into the pages of history. The new battlefields of land and sea now echoed with mighty cannon blasts and the crack of muskets. But it wasn’t long before some of the enterprising new weapons makers figured that since a black-powder explosion could push big iron cannon balls out of the new one-piece cylinders at high speed over and over, maybe a variation on the device could do the same for a piston attached to a wheel or lever with a rod. That would be great, because then they could use it to run all manner of clunky machines to turn the wheels of industry.
After fooling around with a gunpowder engine or two, it became clear that steam was the more practical propellant of choice. The race was on to invent an economical steam engine, culminating in James Watt’s greatly improved design around 1765. The new engines marked the dawn of the industrial revolution and they are the reason designers of new machines are called engineers today.
Left, the barrel becomes a cylinder, the projectile becomes a piston, steam replaces gunpowder; the cannon becomes a steam engine. Steam engines shook society to its core and the ripple effects went far beyond what one might think. When cheap steam power became available, many captains of industry suddenly discovered their moral compass and decided that slavery was an abomination. Mines and foundations could be dug many times deeper than before. That’s why the natural sciences suddenly took off in the first half of the 19th century like, well, a rocket. It was the beginning of modern geology, the idea of an ancient earth, and soon an even more controversial idea about how and why living things change put forth by a young naturalist named Charles Darwin.
Within a few years the new reciprocating engines were so improved they could pull the first trains. Other, more specialized engine designs were harnessed to experimental electric dynamos, and before long the practical electric generator was born. Smaller engines were developed to run the first cars. Some of the most advanced, lightweight engines were eventually attached to a new, heavier than air flying machine called an airplane.
That’s quite an impressive record of spinoffs, huh? From rockets to cannons, from steam engines to electric generators, from trains to planes. But the lucrative benefits from black-powder weren’t done yet, not by a long shot, no pun intended.
The science of thermodynamics, the study of Heat and Work and those properties of substance related to Heat and Work, blossomed as more and more students flocked to engineering. This new class of professionals speculated that if heat put into a steam engine resulted in an output of work, perhaps they could flip the cycle around. Could a sort of reverse engine use work to pump heat out and keep an object cool? It sure could!
Steam becomes a refrigerant; the cylinder and piston become a compressor, the engine becomes a heat pump. Now, at first glance heat pumps may not look like as big a deal as the other black-powder spinoffs. But like the other innovations, they transformed virtually every industry on earth and changed our way of living. For the better, too: ice cream, air conditioning, food and drug preservation, you name it. And in a fascinating circular twist it was refrigeration that made the rocket what it is today.
Cheap, efficient refrigeration meant room temperature gasses like hydrogen and oxygen could be cooled and stored in a liquid state. Liquid oxygen, or LOX, made one constituent in a new type of rocket fuel far more powerful than gunpowder. It wasn’t long before a team of visionary rocket designers toying with liquid fuels in a ravaged post WW1 Germany were funded by a nascent Nazi regime. One of their creations would become the first human artifact to achieve suborbital spaceflight. It is in large part because of them that rockets would soon become synonymous with both the most recognizable, terrifying weapon the world has ever known, and the greatest voyage of peaceful exploration mankind has ever undertaken.
We can only hope it is the latter utility that prevails. For as history amply demonstrates and this brief narrative hopefully illustrates, there are two big drivers of dramatic technological progress and the serendipitous benefits that follow: money and war. The pursuit of profit is not without its pitfalls. But in an era in which the next all out war could easily be fought with nuclear bombs and chemical weapons, one of these drivers has a future, and one of them does not.