NASA's current space transportation goals reflect the belief that customers will require much less expensive, more reliable, and more flexible launch services than are available today. The major cost drivers for today's expendable or reusable launch systems are listed below:

  • amortization of large development costs

  • complex operations: vehicle assembly, checkout of numerous complex interfaces, and launch command and control

  • maintenance, monitoring, and perpetual improvements in hardware designed for performance, not robustness

  • limited reuse of hardware

  • low launch rates

Estimates of the approximate cost per pound to orbit for several U.S. expendable launch vehicles are shown in Table 5-1.

Table 5-1  Approximate Cost per Pound for Major U.S. Launch Vehicles


Cost Per Pound


Low Earth Orbit

Geosynchronous Earth Orbit

Delta II



Atlas IIA



Titan III



Titan IV-SRMU (no upper stage)


Centaur (with upper stage)



Source: Dawson, 1994.

The committee believes that the low-cost attributes of future launch systems will be simplified launch operations, robust design and operating margins, and near complete reuse of hardware. Large design and operating margins will insure long life and minimum checkout and maintenance costs. Complete or near-complete reuse of hardware will keep replacement costs low. Thus, the most viable way to achieve the NASA goals for low-cost access to space is to develop robust, highly reusable launch vehicles (RLVs) with aircraft-like maintenance and frequency of operation. The potential enabling technologies identified by the committee are discussed in the remainder of this chapter.

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