Hybrid Is Born

What makes an airplane so successful? As we saw in the last chapter, it is its inherent efficiency as both an aerodynamic and economic vehicle that accounts for this. Airplanes are mass-produced, plugged into an existing infrastructure, and have long lines of paying passengers clamoring to climb aboard.

The airplane has a lot going for it. Not only does it have people who want to pay for rides, but it has an atmosphere willing to provide free oxygen, glad to exchange aerodynamic lift for a little atmospheric drag, and serve freely as the all-important working mass (Fig. 3.5).

The rocket has a lot going for it as well. It has large energies at its command, and has the capability of reaching the equilibrium state of orbital free-fall, in return for a brief impulse from its powerful engines. Once it reaches orbit, it can shut its engines down completely, and coast around the world for free, essentially forever.

The free components of spaceplane operations, then, will include oxygen from the air, working mass from the atmosphere, and the free-fall of orbit. The prices that must be paid are drag in exchange for lift, and propellants in exchange for speed.

Fig. 3.6 Baby spaceplane X-38 cradles under the wing of its "grandmother" B-52 (courtesy NASA)

Now comes the challenge: combining the rocket with the airplane. They must be integrated successfully, and give birth to a hybrid vehicle with exceptional qualities superior to its forebears (Fig. 3.6). This baby will have far more potential than the dwarf rocketplane X-15, and be far less clumsy than the awkward Space Shuttle. This vehicle, when fully grown, will be able to stand on its own legs (not its tail), and land on its own feet. It will be far better adapted to its environments than either of its parents, flying in the air faster than its airplane "mother," and flying through space farther than its rocket "father." A precious spaceplane is born.

This has been a very short survey of some of the theoretical challenges involved in building spaceplanes. In the remainder of the book, we will look at these issues more in-depth in an attempt to gain some deeper insight.

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Pregnancy And Childbirth

Pregnancy And Childbirth

If Pregnancy Is Something That Frightens You, It's Time To Convert Your Fear Into Joy. Ready To Give Birth To A Child? Is The New Status Hitting Your State Of Mind? Are You Still Scared To Undergo All The Pain That Your Best Friend Underwent Just A Few Days Back? Not Convinced With The Answers Given By The Experts?

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