We have "great observatories" in orbit and NASA's space probes are the first to leave the solar system. NASA's accomplishment on this front are unrivaled, there's little argument about that.

It's the manned program, however, that raises the most ire among space advocates. In this group (of which I am a member) there is wide spread condemnation of the space shuttle and the ISS.

In fact the current manned program is viewed by many as a political "make work" program where a handful of powerful senators receive billions in pork, and in return we get to see highly-orchestrated space walks which are little more than re-runs of what we saw 30-40 years ago.

The disintegration of the space shuttle Columbia seems only to confirm our views. Hard figures now show that flying the space shuttle is 100 times more dangerous than flying a combat aircraft over a hostile Baghdad. How many fighter pilots would we lose if the chances of failure were increased 100-fold?

I suspect our politicians would be demanding that the Air Force increase our success and survivability rate. From the top to the bottom of the political spectrum, changes would be supported, no matter the cost.

And that gives us a glimpse into the difference between the Air Force and NASA. They have two different political realities. One is essential to the security of the country, the other is essentially icing on the cake.

Few politicians would vote against a funding increase for the Air Force if it was in dire need, but far more would vote against a NASA budget increase, even after seeing the Columbia disintegrate on live television.

As much as space advocates would argue otherwise, exploration of Mars and elsewhere beyond Low-Earth Orbit (LEO) is not a national security imperative. In essence, LEO exploration is all we need for security purposes.

It allows us to maintain a sizeable and skilled aerospace workforce, and it keeps rocket factories, machine tools, etc from collecting too much dust. That's about all it needs to do from a security standpoint.

That's the political reality we live in. For those of us who dream of so much more, what do we do? Should we lobby hard for moon and Mars missions? Unless we have millions to give in "campaign contributions", lobbying is unlikely to have any effect.

Should we sit back and hope that Bill Gates will fund a Mars-shot? Don't hold your breath. As a successful businessman, Mr. Gates no doubt realizes he would burn up billions of his own dollars on a mission that would have a high probability of failure, and which even he could not afford to fund indefinitely.

The final option is to radically change the economics of space travel, so business space can achieve critical mass. Only then will competition be created in a marketplace, leading to continuous innovation and increases in efficiency, just as we see today in any earth-bound industry.

The reality of space travel is that it is extremely difficult to accomplish with today's accepted physics (perhaps someday antigravity and warp drive will make it a breeze).

The forces required to launch a vehicle are enormous, and the vehicles must be built with the barest of safety margins, lest they be too heavy to fly at all. Any lighter and they would break apart from the incredible stresses and vibrations of ascent and descent. As we have seen with the shuttle, it flies only when each of millions of parts work perfectly.

Re-entry, as we have been reminded, is also tenuous at best. Essentially, we must convert all the energy we gained on liftoff into heat on re-entry, using the atmosphere to generate friction. Next time you are on the highway, stick your hand out the window and feel the wind blowing on it.

Now imagine winds 300 times as fierce. The closest logical comparison is a meteor crashing into the atmosphere, and we are reminded that the process is so perilous that we use it to burn up space stations and satellites when they are of no use to us anymore.

Today we lack the technology to radically reduce launch costs, which is a prerequisite for a space business. The X-33, even if it had worked, would not have brought cost down and reliability up to the levels expected of commercial airliners.

NASA's "Orbital Space Plane" doesn't even match the X-33 in cost reductions - the OSP is essentially what the shuttle should have been 30 years ago. By no stretch of the imagination can you call it a leap in technology.

No, we need to take a step beyond even the X-33. There are rays of hope on the horizon. Scramjet technology is certainly promising. Many suspect that the Air Force has secretly perfected this technology, but as far as we in the de-classified world know, scramjets are still in their infancy, the first test models only recently flown.

Scramjets are interesting because they allow very high mach numbers (15+) and draw their oxygen from the atmosphere, rather than a huge tank filled with untold tons of liquified oxygen.

This means your craft can be smaller and lighter. Smallness and lightness means the structure of the craft can be built with a larger safety margin and still make it into orbit. With the X-33, very exotic composites were required to achieve enough strength to survive the forces of launch and descent, and the margin of error was not as great as a commercial airliner.

Materials science is also moving ahead. We need higher-tempature high-strength materials to withstand not only the heat of re-entry, but also the incredible forces and temperatures inside a scramjet engine.

The metal heat shield tiles of the X-33 are a good start, but I suspect we can do even better. Carbon nanotubes also offer intriguing opportunities. With a tensile strength of up to 100 times that of steel, it's easy to envision structural laminates and fuel tanks that are vastly stronger and lighter than today's best.

NASA already supports research and development in many of these areas. In fact, many of the advanced materials are the fruits of past attempts by NASA to build a futuristic space plane. In short, NASA is already doing what is politically realistic: they are pushing fundamental R&D while keeping the seat warm for the businessmen of the future.

For those of us in the advocacy realm, we should not abandon the dreams of a Mars trip, or whatever our pet project is, we should instead advocate increased R&D on materials and propulsion sciences.

It's these fundamental technologies that will make space travel possible in the future, not bigger budgets for existing rocket technologies. With another decade of R&D and a handful of materials breakthroughs, our dreams could become a reality.

Tim Perdue tim @NOSPAM@ perdue.net - replace with single @ Community
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