WASHINGTON — Solid-rocket-booster manufacturer ATK is asking the U.S. Air Force to consider a solid-fueled rocket motor to replace the Russian-made engine that powers United Launch Alliance’s Atlas 5 rocket.

In its formal response to an Air Force request for information on future launch options, Promontory, Utah-based ATK Aerospace positioned solid-rocket motors as a relatively near-term replacement for Atlas 5’s kerosene-fueled RD-180 engine, citing the company’s quick development of six new solid motors, some of which were completed in less than two years.

“By combining our extensive experience with new technologies, we have provided commercial customers with low-cost solutions that progressed from design to flight qualification within months,” ATK Aerospace President Blake Larson said in a Sept. 23 press release. “Using a similar approach, ATK’s propulsion solution will provide the U.S. Air Force with an RD-180 replacement rapidly and at a highly competitive cost.”

Liquid-fueled rocket engines generally take longer to develop. The rule of thumb for developing new liquid-fueled engines, ULA Chief Executive Officer Tory Bruno told reporters Sept. 17, is 7-10 years and $1 billion.

Bruno said the lengthy timeline for scratch-built engines was a major factor in ULA deciding to partner with Blue Origin on the completion of BE-4, a liquid natural gas-fueled rocket engine the secretive Kent, Washington-based company has been working on for three years. At a Sept. 17 press conference announcing the partnership, Bruno said a test flight of an Atlas 5 rocket powered by a pair of BE-4 engines is targeted for 2019.

The request for information the Air Force issued Aug. 21 invited aerospace firms to share their ideas for assuring the United States can continue to launch classified satellites and other high-priority payloads. The U.S. government is considering options ranging from developing new rocket engine technology to building a new launch vehicle.

The request was triggered by concerns over the future availability of the Russian-made RD-180 — the main power plant for United Launch Alliance’s Atlas 5 rocket — as U.S. tensions with Russia escalate over the crisis in Ukraine. The Atlas 5 is used, along with ULA’s Delta 4 rocket, to launch the lion’s share of U.S. national security, weather and scientific satellites.

While ULA is banking on Blue Origin to provide an eventual replacement for the RD-180, Defense Department officials have said repeatedly in recent weeks that the government would be open to a solid-rocket solution.

ATK touts solid-rocket motors as particularly suited for a launcher’s main stage because they provide smooth lift for payloads, which could prove important while launching sensitive national security satellites. They also require less ground and launch infrastructure, the release said.

Mike Gruss covers military space issues, including the U.S. Air Force and Missile Defense Agency, for SpaceNews. He is a graduate of Miami University in Oxford, Ohio.