Redundancy -- NASA needs two different CEVs and boosters

[gunsandrockets]

Update, new launcher news from space.com<br /><br /><br /><br />http://www.space.com/news/050810_dod_launcher.html<br /><br /><br /> <br /> <br />---The two-page letter says “NASA will initiate development of a Crew Launch Vehicle derived from Space Shuttle solid rocket boosters with a new upper-stage for human spaceflight missions in the 25-30 metric-ton-class following retirement of the Space Shuttle in 2010. NASA then plans to develop a new 100 metric-ton-class launch vehicle derived from existing capabilities with the Space Shuttle external tanks and solid rocket boosters for future missions to the Moon.”---<br /> <br />---The letter also says NASA and the Pentagon will use the Atlas 5 and Delta 4 rockets developed under the U.S. Air Force’s Evolved Expendable Launch Vehicle (EELV) program “for all intermediate and larger payloads for national security, civil, science, and International Space Station cargo re-supply missions in the 5-20 metric-ton-class to the maximum extent possible.”--- <br /> <br />---The letter further noted that new commercially developed launchers, should they become available, will be allowed to compete for such missions.---<br /><br /><br />