On 2005-02-23, Reed Snellenberger wrote:

Do you mean a version of the Atlas V with two RD-180s? I hadn't heard
that one before -- and am having a hard time imagining it.

The Atlas V Mission Planners guide has some details - Pages 8-9 and
8-10. See http://www.ilslaunch.com/missionplanner/ (They want your
email address...) You want section 8.0

Instead of a 3.8m diameter core, it would require a 5.4m version,
closer to the diameter of the Delta IV's core.

Iain