The U.S. Government–sponsored Evolved Expendable Launch Vehicle (EELV) program was intended to develop affordable alternatives to legacy medium-to-heavy-lift launch vehicles (e.g. Titan, Delta III). The program resulted in the development of two vehicles:
The program supported two fully independent design efforts to ensure that any future design, manufacturing, or supply problems would not jeopardize the U.S.' heavy-lift access to space. It was presumed that the commercial launch market would support two new vehicles, but demand in the first half of the 2000s has been lower than expected, due to the downturn in the commercial spacecraft market during that time, and a perceived trend toward smaller spacecraft. It is possible that one of the EELV competitors will be eliminated by the Department of Defense in 2009, due to insufficient launch volume. However, that is by no means definite, and if the launch market picks up, then there would be no need to make such a decision.
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