Rocket Men

To Infinity...And Beyond!

President Bush has outlined his plans for returning Americans to the moon, establishing a permanent base there, and then going on to Mars. Of course, you all knew that, and I'm just finally getting around to the topic.

I remember, when I was a kid in junior high school, my dad driving around our city with a big American flag waving out the window of our car, honking the car horn, and generally carrying on when Neil Armstrong and Buzz Aldrin made the first moon landing. It was actually one of the most embarrassing moments of my life. I slunk down in my seat as low as I could, so no one would recognize me. I mean, I was really proud that our country could do something so cool, but come on, Dad!

Looking back at that accomplishment from over thirty years later, I can see why he was so enthused. America hasn't succeeded at meeting a scientific or engineering challenge that big since those days in the 60's and 70's. I don't want to believe that our ability to accomplish big things has become stunted. In these times, are we only ready for a difficult challenge if it involves war? If that's true, it's a sad indictment of our country and culture, and it concerns me.

I don't see a lessening in our scientific or engineering capability. I think we've become stunted in our policy and in our imagination. What has happened to our can-do spirit? The spirit of inventiveness and of pushing the envelope has always been one of the hallmarks of the American character, and I see it perhaps slipping away.

I hope I am wrong about that.

But, in these times of political correctness, it appears to me that it's somehow wrong to be too successful - it makes those less successful feel bad. Since we're the hyper-puissance, we must be sensitive to those less fortunate. So many people believe that all of the money that we spend on expanding our horizons and accomplishing great things - like going to planets beyond our own - is money wasted. They believe that it should be spent on the poor, or the environment, or researching cures for disease, or in some other politically correct way.

None of those things are wrong, by any means. They just aren't enough.

History shows, I believe, that over the long term, the best way to reduce suffering in the world is to raise the average standard of living for everyone. How does that happen? Through advancement of science and technology, as well as through good government and good policy. It isn't an accident that, in general, the countries that value freedom are also the most technologically advanced and have the lowest levels of poverty. All of those things are intertwined. Freedom gives individuals and corporations the incentive and opportunity to pursue technological advancements in all areas (including food production). Freedom also allows each individual to pursue opportunities to improve his or her life through education and employment. Freedom produces competition, which gives individuals more choices, which encourages technological progress. Freedom and technology work synergistically to raise the overall standard of living.

And so, I am supportive of pushing forward into space, and I generally support the vision outlined by President Bush. Humanity as a whole will benefit from the scientific and technological progress that moving into space will require. Of course, science and technology will progress anyway, but solving the difficult problems that moving into space will pose will require scientists and engineers to stretch, exercising their knowledge and creativity to the utmost. Over the long term, it also will inspire young men and women to learn and grow, so that they can take part in the opportunities in science and engineering arising in all fields. The new generation of scientists and engineers will create new technologies that will raise our standard of living, benefiting the whole world.

It is too easy, in our concern for the poor and disadvantaged of the world, to become stunted in our thinking - to lose our drive for the future, weighed down by the burdens of the present. We should not let that happen. To relieve the burdens of the present - poverty, disease, violence - we must invent new ways to lighten the load. We must think big thoughts and overcome enormous challenges. Moving into space and on to new worlds is just such a challenge.

Hybrid Vigor

That previous bit of thought was inspired by a post on Instapundit on hybrid rocket engines.

All rocket engines use two chemical components to produce thrust: a fuel and an oxidizer. This is no different than any other system that burns something; for example, your fireplace combines wood - the fuel - and oxygen in the air - the oxidizer - to produce heat and light. A jet engine combines jet fuel and oxygen in the air to produce heat and thrust. A car engine burns gasoline with oxygen from the air to produce heat and mechanical power.

A rocket engine is different from typical engines (like a car engine or jet engine) because it can't directly use oxygen from the air as the oxidizer when it burns its fuel. It must carry its oxidizer with it.

In the past, there were two basic types of rocket engines: solid fuel rocket engines and liquid fuel rocket engines. The space shuttle uses both types.

The shuttle's main engines are liquid fuel engines. They burn liquid hydrogen and liquid oxygen that is stored in the huge external fuel tank that the shuttle is strapped to. Pieces of hard insulating foam coming off the external fuel tank and hitting the shuttle wing were what caused the shuttle Columbia to break apart when it re-entered the atmosphere on its last flight. Liquid fuel rocket engines have the advantage that they can be throttled up and down, or even shut off, like a car engine, but they are very complex and expensive. The liquid fuels are often very dangerous and difficult to handle.

The two rockets strapped to either side of the space shuttle's main fuel tank are solid fuel rockets. Solid fuel rocket engines are really very simple. You very well may have even fired one yourself, right around July 4th. (Roman candles and bottle rockets are solid fuel rockets). They are, more or less, a firecracker with one end left open. When a solid fuel rocket is lit, the hot gases formed when the fuel burns rush out the nozzles on the open end, producing thrust. As you might guess, solid fuel rocket engines are cheap compared to liquid fuel rocket engines, but they cannot (typically) be throttled or shut off once they are ignited, and they can be very dangerous if not properly constructed. The shuttle Discovery blew up when one of the solid fuel rockets malfunctioned due to cold weather and a design flaw, causing it to explode.

For many years, engineers have researched methods of constructing a rocket engine that is inexpensive and simple like a solid fuel rocket engine, but can be throttled or shut down like a liquid fuel engine, and is also much less dangerous than either. It appears they have succeeded with a hybrid rocket engine.

Hybrid rocket engines are rocket engines that use fuel that is in one phase of matter (usually a solid) and oxidizer that is in another phase of matter (usually a liquid). They are called hybrid engines, because they are a hybrid (a cross) between a solid fuel rocket engine and a liquid fuel rocket engine, and they appear to have the advantages of both, with the disadvantages of neither. That is, they are simple and cheap to build, but (in the more advanced examples) they can be throttled or shut down. The fuels and oxidizers used are generally safe and relatively easy to handle. In fact, for several years hobbyists have been building powerful rockets using hybrid engines that use PVC plastic (the type of plastic used for sprinkler system pipe) as the fuel and laughing gas (nitrous oxide, or NOx) as the oxidizer! Lately, engineering students have built a hybrid engine that uses candle wax as the fuel. Even table sugar has been used as a hybrid fuel. No, I'm not joking! This all works, believe it or not. Some of the hybrid engine rockets have reached altitudes of over 20,000 (yes, twenty thousand) feet!

Why am I so enthused about all this? Well, for one, I'm a geek, and I just think this stuff is way cool. I had a small model rocket when I was a kid in junior high school (one of the Estes kits that I built), and I flew it several times. It was a blast, and I hope I can get my son interested in model building and rocketry when he's a bit older.

Second, the fact that engineering students and hobbyists are advancing technology in this challenging field, developing and flying new types of rocket engines, points out exactly what I was writing about previously. These people are having fun, and they have the spirit of inventiveness. I lamented its apparent waning above, but these hobbyists, inventors and students prove that it isn't dead yet. Will George W. Bush's re-focus of NASA take hold and re-energize it with that same spirit - the spirit it had in the days of "the right stuff" and the moon landings? I certainly hope so. NASA will need it to succeed, and success on that scale will give me hope for the future of our country.

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