4th Space Launch Squadron

The 4th Space Launch Squadron is the Air Force's Evolved Expendable Launch Vehicle (EELV) launch agency for the West Coast. The EELV program was initiated in order to develop affordable alternatives to older, obsolete, and expensive heavy-lift launch vehicles, such as the Titan IV. The big deal with EELV is that the system is comprised of a Common Booster Core, or CBC, which is a liquid-fueled first stage that can be used alone, with strap-on solid rocket boosters, or as a configuration of three CBCs tied together.

Delta IV

This is Boeing's EELV. See attached schematic for the many different possible configurations. The one launched in June was a Delta IV Medium Plus (it had two Graphite Epoxy Motors (GEMs) strapped to the side). There are many different configurations for the Delta IV, capable of lifting anywhere from 9,000lb - over 13,000 lb into Geosynchronous Orbit.

Atlas V

This is Lockheed Martin's EELV, and the first launch from Vandenberg is scheduled for this spring. Also with many different available configurations, this system can lift between 10,000lb and 30,000lb to Geosynchronous Transfer Orbit.

Delta II

This is a heritage vehicle and is much smaller than the newer Delta IV. The Delta II can have up to nine Graphite Epoxy Motors that can be strapped to it's main stage, increasing lift capability. The Delta II can send approximately 4,000lb into Geosynchronous Transfer Orbit.