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Reid: In 1920, when physicist Robert Goddard first proposed that a rocket could one day carry a payload to the moon, none other than the New York Times called him out, saying that the notion of a rocket producing thrust in the vacuum of space without any air to push against was absurd.  Goddard's response?  "Every vision is a joke until the first man accomplishes it.  Once realized, it becomes commonplace."

Born way before the space age in 1882, Robert Goddard is today considered one of the original rocket scientists.  Although his genius wasn't widely recognized during his lifetime.  Robert didn't invent the rocket itself, but he did build and test the world's first liquid fueled rocket, the basic design of which continues to be used today.  

Strictly speaking, rockets are simply devices that obtain thrust by releasing gases at high speeds, usually by burning some kind of fuel.  By this definition, credit for the first rocket goes to the 9th century Chinese chemists, who discovered that when you combine saltpeter, sulfur, and charcoal, you have gunpowder.  And when bamboo tubes are filled with that gunpowder and ignited, you have fireworks, which are rockets until they explode.  

Goddard's earliest work focused on the same basic concept as he tried to improve solid propellant rockets fueled by gunpowder.  But by 1915, while teaching physics in his hometown of Worcester, Massachusetts, he began to suspect that a rocket could be better propelled using a more complex liquid fuel.  Goddard came up with a design for a rocket that fed liquid fuel under great pressure into a combustion chamber, along with an oxidizer, a compound that supplies oxygen to make combustion possible.  Goddard thought that if the flow of both materials into the combustion chamber could be controlled, then you could actually regulate the speed of the rocket, even turn it off and restart it, something that fireworks definitely didn't allow for.  

In time, he developed a prototype that used gasoline as fuel, and oxygen as the oxidizer, each running separately into the combustion chamber.  Now you don't have to be a, well, rocket scientist to know that gasoline plus pure oxygen plus ignition equals kaboom!  So, Goddard had to figure out how to keep the combustion chamber from simply exploding once he ignited the propellants.  He did it by making a pretty simple but revolutionary modification--he used extremely cold liquid oxygen as the oxidizer.  By running pipes full of liquid oxygen around the outside of the combustion chamber, he kept the chamber cool while also making the rocket more efficient because less energy was lost as heat.  This method proved so effective that it's still used today.  

On March 16, 1926, in Auburn, Massachusetts, Goddard successfully tested the world's first liquid powered rocket.  The flight lasted less than 3 seconds, with the rocket reaching an altitude of 12.5m and landing 56m away.  Over the next 15 years, Goddard would successfully launch 35 more liquid fueled rockets, including one on March 26th, 1937 that reached an altitude of 2.73km in 22 seconds.  He continued to improve on the design, adding gyroscopes to control motion and even a primitive steering system attached to the exhaust jet.  

Goddard would also prove to be right in his belief that a rocket didn't need a medium, like air, in order to produce thrust.  According to Newton's Third Law of Motion, every action has an equal and opposite reaction, so Goddard knew that while the rocket would push its exhaust backward, the exhaust would likewise push the rocket forward, whether there was air around it or not.  Starting just a year before his death in 1945, scientists around the world would demonstrate that rockets can travel to and through space just fine, thank you, from German V-2 rockets to Sputnik to the Apollo program.

As for that 1920 New York Times editorial?  On July 17, 1969, 24 years after Goddard's death but 3 days before the Apollo-11 landed on the moon, the paper finally corrected its criticism of Goddard.  The correction read, "It is now definitely established a rocket can function in a vacuum as well as in an atmosphere.  The Times regrets the error."  Better late than never, I guess!

Thanks for watching this episode of SciShow Space.  If you want to learn how you can help us keep exploring the universe together, go to Subbable.com/SciShow, and don't forget to go to YouTube.com/SciShowSpace and subscribe.

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