As a kid, in the days leading up to the Fourth of July, I was almost as excited as I was at Christmas. It was even better in some ways; the presents in the form of fireworks were freely available in advance of the big day. In fact, we used to think it was great fun to shoot bottle rockets at each other—not that anyone is condoning that now!
The fuel and technicolor additives for many fireworks has changed over time, but one good ole-fashioned ingredient can still be found in many of them. The rockets that carry satellites and may one day help bring critical resources back to a crowded planet started out as fireworks not too different from the ones that will carry dazzling pyrotechnics to low altitude this week.
If you follow one arbitrary line over the course of a millennium in the long development of that stuff, and follow this post below, its effect on culture will lead to a few surprising places. There might even be a fun lesson or two in the bargain.
Alchemists working quietly before the dawn of the first millennia weren't known for their openness. Many were working on turning base metals into gold or creating potions conferring immortality. Many were just as concerned with fleecing the nobility as they were in developing new chemistry and devices, and they kept their methods secret. But around the turn of the first millennium, tales of a wondrous new substance began to make their way by land and sea from an exotic place far to the east via the new trade routes stretching from modern-day China to Europe. The mysterious new substance was called black powder.
The simple balloon rocket
One of the neat things about black powder is it could power a rocket, making those rockets among the very first artificially powered items on Earth. The powder would expand violently when burned and, similar to compressed air in a modern balloon, blast out the back, only with fiery effect, pushing the whole contraption forward and often upward. But it didn't take the powers-that-be long to realize that if the new powder could be ignited in a strong metal tube of some kind, it might blast a projectile farther than the catapults of the day—with devastating results. Fill the flying projectile with more of the magic substance and it might fragment high over the field of battle, killing the enemy on an industrial scale!
It sounds easy in principle, but a new and entirely new field of metallurgy had to be born to create specialized metal tubes that could withstand the firing stress, some of which no doubt failed with catastrophic results along the way.
The rocket becomes a cannon!
After decades of work, the first practical cannons were born. It took more decades and a great deal of work before a reliable, smaller version was slowly perfected that could be held and aimed by a single person, and that could blast smaller holes in individual combatants. It is no coincidence that this invention marked the beginning of the end of the era of swords, battle axes, and exquisite suits of armor that had dominated battlefields for millennia. Thankfully, progress didn't stop there.
Medieval weapons developers realized early on that if black powder could shove a big iron ball out of a tube over and over again, perhaps the cannon could be adapted to do the same for some of sort block that would move to and fro. Which would be great! Because it could attached to gears and mechanical wheels that might perform all manner of menial tasks heretofore relegated to slaves and animals, or the occasional well-positioned waterfall.
Steam replaces powder; the cannon becomes an engine
This too, took centuries to work out, even a gunpowder-powered engine was tried. But it soon became clear that steam was the ideal propellant, culminating in James Watts'
improved design in the late 18th century. Watts' innovation was among the first practical, affordable steam engines. This new emphasis on engines explains why those early eggheads who fiddled around with various designs and quantified the lucrative science behind them, became known as
engineers.
After more trial and error, a variation of the reciprocating steam engine was developed that could use refined petroleum to heat and expand the air. An even more advanced version was created using the heat produced by steam or gasoline that turned a fan, an idea no doubt taken from the windmills that had dotted farms far and wide all over the world for centuries. But there was more in store for the ancestors of cannon and blackpowder!
Some early engineers dared to dream that if they could put heat into an engine and get work out, maybe they could reverse the process by putting work in and pumping heat out? This was a little trickier and less intuitive than cannons or steams engines. In fact, a whole new science had to be refined: thermodynamics, the study of heat and work and those properties of substance that relate to heat and work.
The engine becomes an AC
After more trial and error—and advances in chemistry creating a new class of substances ideal for transferring heat out of a system operating more or less at room temperature—the first mass-produced heat pumps hit the market and soon popped up in virtually every corner of America. Today we know those heat pumps by the more familiar name of refrigerators and air conditioners. And I believe I speak for everyone who has read this far on a summer weekend: who doesn't appreciate ice cream and air conditioning?
It's interesting to note that our entire civilization was built on just a handful of developments, several arising directly and indirectly from black powder and weapons research: the reciprocating engine, the turbines at the heart of power plants, the electrical power those devices make possible, and the refrigeration critical to everything from food distribution to the precise temperature control needed in the heart of nuclear power plants. Not too bad for ancient inventors who came up with a curiosity called black powder. And it wasn't done yet.
U.S. Army V-2 cutaway drawing showing engine, fuel cells, guidance units and warhead. (U.S. Air Force photo)
It was refrigeration that would complete the circle, at least as far as this essay goes. Beginning in the years after World War I,
early rocket designers began to experiment with different kinds of fuels for those rockets their antecedents had once sent flying with black powder. They tried various explosives and eventually liquids, including super-cooled hydrogen and oxygen, along with other elements or compounds, and found mixes that were far more powerful. By the height of World War II, one team of designers had
just about perfected the first intercontinental ballistic missile, a vehicle that could reach space, and the direct ancestor of every ground-to-orbit rocket that would follow, including the mighty Saturn V that sent humans to the moon in 1969.
Fireworks have come a long way over the last thousand years, but there is plenty of room for future progress. The rockets they helped inspire may yet help deliver the virtually unlimited resources of the solar system and beyond to an increasingly crowded Earth. By the end of this century, they may even play a critical role in securing the long term survival of our entire species:
Once upon a time, space travel was purely the province of governments, which viewed it as an ancillary extension of their power and prowess. But in recent years, a "new space" movement has fueled the growth of a commercial space industry that is in large part backed by American billionaires and their seemingly wild goals of colonizing Mars, transforming humans into a "multi-planetary species" and making space travel the next tourist attraction.
Which brings up an important question: what drives technology the best, war or profit? War has quite a track record: if necessity is the mother of invention, raw survival is one hell of a midwife. And the pursuit of profit is not without its shortcomings—there is ample opportunity for corruption and enormous chasms of inequality often arise. But in a time when the next all-out war could be fought with ballistic missiles tipped with nuclear and chemical weapons, one of those drivers has a viable, survivable future and one of them does not. Worth keeping in mind as you gaze at twilight skies this week, hopefully with an overflowing ice-cream cone in hand, and enjoy pretty fireworks celebrating the Fourth of July.
Update: An unmanned SpaceX launch vehicle failed two minutes into flight this morning. No one was hurt -- DS