More on the HLLV RP-1, the proposed successor to the Shuttle using liquid fuel and Russian technology

The Orlando Sentinel has a bit more information for us on the HLLV RP-1, in my opinion the most interesting of the five designs for rockets that could be developed in place of the Ares in order to lower costs. It's the most interesting of the five because it doesn't rely on Shuttle technology and thus does not need solid rocket boosters, would use some Russian technology and would be both the largest of the five as well as the cheapest.

The Russian engine it would use for the first stage is called the RD-180, and the first stage would use five of them. This would not actually be the first of its kind as the Atlas rockets also use this engine.

Other good points are improved ground operations safety, and maintenance (the rocket would be lighter when being set up for example as it would be set up empty and then would be fueled).