[Dec. 19, 1959] Like Water for Rockets (The testing of the XLR115)

In other news, the XLR-115 rocket was successfully tested on December 7, 1959.

State Archives of Florida, Florida Memory, http://floridamemory.com/items/show/31535

I see you scratch your head.  “Is that important?” you wonder.  “Aren’t rockets tested all the time?”

Yes and yes.

You all have heard of Newton’s Third law, “For Every Action, there is an Equal and Opposite Reaction.”  This principle powers our rockets: through the controlled rapid combination of fuel and oxygen (also known as burning), exploding gasses are produced, which are given a hole at the base of the rocket through which they can escape.  This action propels the rocket in the opposite direction—up, hopefully.

The heavier the rocket, the more fuel it takes to send it into space.  Fuel is by far the largest component of any rocket through most of the rocket’s flight (until it is all used), so it stands to reason that one would want the lightest, most efficient fuel possible.

Up to now, rockets have used familiar fuels, from petroleum derivatives to alcohol, because they are relatively cheap and easy to manipulate.  To break the weight barrier, one needs a truly light material, preferably the smallest stuff that could possibly oxidize.  Hydrogen happens to be the lightest element possible, Atomic Number One.  It burns: most of you know the chemical nomenclature for water is H2O, which simply means that any molecule of water comprises two atoms of hydrogen and one of oxygen.  Water is, essentially, burnt hydrogen. 

If one could bottle hydrogen safely in a rocket, then it would be the most efficient rocket fuel possible.

It’s a tough project.  It won’t do for the hydrogen to be kept in gas form, as in a World War I zeppelin.  That would result in an overlarge rocket and very elaborate mixing and ignition mechanisms.  No, you need to store the stuff in liquid form, and that takes a very cold and very good Thermos, indeed.  Just a few years ago, the idea of using liquid hydrogen as rocket fuel was as much science fiction as hyperspace and flying cars.

Until now.  The XLR-115 is a liquid hydrogen rocket.

Thus, the next generation of rocketry has begun.  At first, the XLR-115 will be used in the Centaur second stage, allowing boosters like the Atlas to send large payloads to high orbit, the moon, and the planets.  Ultimately, the liquid hydrogen rocket will likely be a vital component is the first manned lunar rocket. 

And that’s why this news is important.  Now you know.

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P.S. Galactic Journey is now a proud member of a constellation of interesting columns.  While you’re waiting for me to publish my next article, why not give one of them a read!

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