Upside Down Space Shuttle by Robert Zubrin
The Shuttle is a fiscal disaster not because it is reusable, but because both its technical and programmatic bases are incorrect. The Shuttle is a partially reusable launch vehicle: Its lower stages are expendable or semi-salvageable while its upper stage (the orbiter) is reusable. As aesthetically pleasing as this configuration may appear to some, from an engineering point of view this is precisely the opposite of the correct way to design a partially reusable launch system. Instead, the lower stages should be reusable and the upper stage expendable. Why? Because the lower stages of a multi-staged booster are far more massive than the upper stage; so if only one or the other is to be reusable, you save much more money by reusing the lower stage. Furthermore, it is much easier to make the lower stage reusable, since it does not fly as high or as fast, and thus takes much less of a beating during reentry. Finally, the negative payload impact of adding those systems required for reusability is much less if they are put on the lower stage than the upper. In a typical two-stage-to-orbit system, for example, every kilogram of extra dry mass added to the lower stage reduces the payload delivered to orbit by about 0.1 kilogram, whereas a kilogram of extra dry mass on the upper stage causes a full kilogram of payload loss. The Shuttle is actually a 100-tonne-to-orbit booster, but because the upper stage is a reusable orbiter vehicle with a dry mass of 80 tonnes, only 20 tonnes of payload is actually delivered to orbit. From the amount of smoke, fire and thrust the Shuttle produces on the launch pad, it should deliver five times the payload to orbit of a Titan IV, but because it must launch the orbiter to space as well as the payload, its net delivery capacity only equals that of the Titan. There is no need for 60-odd tonnes of wings, launching gear, and thermal protection systems in Earth orbit, but the Shuttle drags them up there (at a cost of $10 million per tonne) anyway each time it flies. In short, the Space Shuttle is so inefficient because it is built upside down.
Additional inefficiencies in the Shuttle stem from the vehicle's birth and consequent design as a make-work project. The demands of the Apollo program gave rise to NASA as the large federal agency it is today. As Apollo drew to a close, the agency and its political allies required something for its large workforce of civil servants and private contractors to do. Unfortunately, rather than give this formidable army of technical talent a project worthy of it -- the establishment of permanent human out posts on the Moon and Mars - the Nixon administration chose to maintain the agency in idle mode. The Space Shuttle program was the result. In other words, the de facto requirement of the Shuttle program was not that it accomplish anything, but that it keep a lot of people busy. In this latter quest it has succeeded admirably, but such success is exclusive to the goal of achieving low launch costs. No matter how reusable a system is, if you run an eight-launch-per-year medium-lift launch program that must nevertheless pay for the employment of 50,000 people, it's just not going to be cost effective.
Source: Page 29-30, ENTERING SPACE, by Robert Zubrin
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