The development of the next -- and possibly last -- generation of advanced expendable cargo rockets continues towards an inaugural launch in 2001. The new rockets, families of space carrier vehicles each designed by the two largest U.S. space booster companies, Lockheed Martin and Boeing, are designed to eventually replace today's existing fleets of Delta, Atlas, and Titan boosters by the middle of the next decade. Considering the current series of launching disasters that have nearly grounded most U.S. satellites since spring, the coming of the EELV (Evolved Expendable Launch Vehicle) might not be a moment too soon for U.S. space launch leadership.

The reason has as much to do with the past history of American rocketry as future competition. Beginning in the late 1950's the first generations of U.S. ballistic missiles were named Atlas, Thor, and Titan. While these missiles were developed to lift nuclear warheads thousands of miles through space to targets in the Soviet Union or China, they were also quickly adapted for launching cargos of satellites and man-carrying space capsules. By the early 1970's, however, with NASA budgets drastically reduced following the Apollo moon landing program, development of a reusable space vehicle -- the space shuttle -- became a priority at NASA. All existing launchers of the time, the Atlas, Delta (which was the final evolution of the old Thor missile), and Titan were to be terminated and every U.S. satellite was to ride aboard the shuttles.

As a result of this decision by the Nixon administration, further development of U.S. rockets was stopped. The industry for them was to be dismantled. But the fleet of four NASA shuttles proved unable to carry out as many annual launches as would be needed to be the sole U.S. carrier rocket, so the Reagan administration restored commercial rockets as alternatives to the shuttles in 1985.

The Challenger shuttle disaster the following year and the resulting delay in launch schedules forced even greater emphasis on expendable rockets. But the designs of these rockets were still based on the ballistic missiles of the 1950's, although with as many new features as could be retrofitted onto the vehicles. The result were rockets that still cost anywhere from $40 million to $700 million each, with the cost of lifting satellites as high as $10,000 per pound.

Following extensive studies, the Air Force decided in 1995 to scrap the existing designs for an entirely new family of boosters and stages. Mandated in the contracts were the requirement that at least a 25 percent cost savings over existing designs be achieved-and possibly as much as 50 percent.

The Boeing Delta IV and Lockheed Martin Atlas V, while retaining the names of the famous rockets that started the Space Age, are intended to usher in a period of lower cost, flexible space transportation, as advanced a ride into space as possible on a chemical, throw-away rocket.

Until the newest reusable space vehicles of the 21st century begin flying U.S. skies, the EELV family will be the nation's answer to more affordable space transportation.