I have vivid memories from when I was a kid in Texas of travelling out into the countryside to watch my oldest brother and his friends launch rockets.
This wasn’t some ’60s radicals’ attempt to overthrow the government of Swisher County, but a new hobby called model rocketry. The rockets came in all sizes, from three or four inches tall to three-foot models of the Saturn V moon rocket. They would hurtle hundreds of feet into the sky before popping off their balsa-wood nose cones to release parachutes that brought them safely (most times) back to Earth to be launched again.
I thought those model rockets were the coolest thing I’d ever seen, and 35 years later, I still think rockets are cool.
The principle of the rocket is quite straightforward: a fuel and an oxidizer burn together in a combustion chamber, producing hot gases which are discharged through a nozzle. As Isaac Newton noted, “For every action there is an equal and opposite reaction,” so when the hot gases go spewing backward out of the combustion chamber, an equal force pushes the combustion chamber (and the rocket it’s inside) forward.
Contrary to what is sometimes thought, the rocket doesn’t fly by “pushing” its exhaust against the ground or the air. Newton’s Third Law of Motion doesn’t care whether you’re on the ground, in the air, or in the vacuum of space: as long as that exhaust is rushing out of the rocket in one direction, the rocket is going to have to move the other direction.
That’s one reason rockets are used for space travel. The second reason is that since the rocket contains both fuel and an oxidizer, it doesn’t need air, unlike the jet engine.
Rockets were probably invented in China. There are records of them being used in warfare there in the 13th century, while in Europe and the Middle East, where they were also being used at that time, they were called “Chinese arrows.”
Rockets remained primarily military weapons (except for fireworks) until a Russian schoolteacher, Konstantin Tsiolkovsky, established in 1883 that rockets would work in a vacuum and began theorizing about space travel. He sketched spaceships fueled with liquid oxygen and liquid hydrogen or kerosene, advocated multi-stage rockets (in which each stage is discarded as its propellant is used up, lightening the load and allowing the upper stages and payload to reach higher and higher velocities), and even described spinning space habitats where people could live under artificial gravity.
Tsiolkovsky theorized; American inventor Robert Goddard put those theories into practice. He built the first liquid-propellant rocket and launched it on March 16, 1926, at Auburn, Mass. Fueled by liquid oxygen and gasoline, it soared all of 12.5 metres high, reached a speed of 100 kilometres an hour, and landed 56 metres from the launch stand.
The advantage of liquid-fueled rockets over solid-fueled rockets is that liquid-fueled rockets can be throttled up or down or even shut off, whereas solid-fueled rockets, once ignited, burn until they’re burned out. Both advanced a long way over the next few years, especially with the Second World War and the ensuing Cold War to spur things along. The most famous rocket of the Second World War was the German V-2, and the scientists who developed it mostly ended up in either the U.S. or Soviet rocket programs after the war. In just 10 years, rockets went from being capable of delivering chemical explosives a few hundred kilometres to being capable of dropping a hydrogen bomb into the middle of another continent–or launching a satellite, or human, into orbit.
The Saturn V, developed primarily under the direction of German scientist Werner Von Braun, stood almost 10 times taller than Goddard’s first rocket even flew (110.6 metres with Apollo spacecraft attached), and developed 3.45 million kilograms of thrust at launch from liquid oxygen and kerosene (the two upper stages used liquid hydrogen), just as Tsiolkovsky proposed. Just 43 years after Goddard launched the first liquid fueled rocket, it put men on the moon.
Which is the real reason I think rockets are cool. Aside from their obvious kid appeal–loud noise and lots of fire and smoke–they’re the latest iteration of the human desire to explore that took us first beyond the forest, then beyond the horizon. Now we’re exploring beyond our world, and rockets are taking us there.
Don’t you wish you could hitch a ride?