An Atlas 5 rocket prepped for NASA’s Lunar Reconnaissance Orbiter (LRO) mission. Photo: NASA/Kim Shiflett

[Via Satellite 12-24-2015] United Launch Alliance (ULA) announced Dec. 23 that the company had ordered additional RD-180 engines for Atlas 5 missions to serve existing and potential civil and commercial launch customers. The new order of the Russian-built engines will keep the Atlas 5 in use until an American-made replacement can be developed and certified.

Two companies — Blue Origin and Aerojet Rocketdyne — are producing alternative engines for the Atlas 5, as well as ULA’s next generation launch vehicle, Vulcan. Blue Origin’s BE-4 engine completed 100 staged combustion tests earlier this summer, and Aerojet Rocketdyne’s AR1 passed a major design review this month. Currently, Blue Origin is ULA’s primary engine partner, with Aerojet Rocketdyne developing the AR1 as backup. ULA said in a statement that the company agrees with moving to a domestically produced engine, but cautioned that a smooth transition is necessary.

“This type of development program is difficult and takes years to complete. Until then, this bridge contract will allow ULA to provide the reliable, affordable launch services our civil and commercial customers depend on from us while the new, American engine is being developed,” ULA said.