Delta IV Heavy
It is similar to the Medium+ (5,2), except that it uses two additional CBCs instead of using GEMs. These are strap-on boosters which are separated earlier in the flight than the center CBC. The Delta IV Heavy also features a stretched 5-meter composite payload fairing. An aluminum trisector (3 part) fairing derived from the Titan IV fairing is also available. The first launch in 2004 was a test launch only. Its first payload was the DSP-23 satellite.
Capacity (separated spacecraft mass) of the Delta IV Heavy:
- Low Earth orbit (LEO) 22,950 kg 
- geosynchronous transfer orbit (GTO) 13,130 kg (28,950 lb).
- geosynchronous orbit (GEO) 6,275 kg
- escape orbit 9,306 kg
- C3 performance of 30 km2s−2: 5,228 kg
- C3 performance of 60 km2s−2: 2,521 kg
The Heavy's total mass at launch is approximately 733,000 kg, much less than that of the Space Shuttle (2,040,000 kg), but is not reused.
Comparable Vehicles 
- "Boeing Delta IV Heavy Achieves Major Test Objectives in First Flight", Boeing, 2004, accessed March 22, 2012
- "Delta Launch 310 – Delta IV Heavy Demo Media Kit - Delta Growth Options". Boeing.
- US Air Force - EELV Fact Sheets
- "Delta IV Payload Planners Guide". United Launch Alliance. September 2007. pp. 2–5.
- Bergin, Chris (2012-01-18). "EFT-1 set to receive Spring, 2014 launch date after contract negotiations". NASASpaceFlight.com. Retrieved 21 July 2012.