WASHINGTON — With billions of dollars in potential business at stake, U.S. rocket and propulsion providers are emphasizing their respective strengths as they counsel the U.S. government on a new launch vehicle strategy that industry sources say could be decided before the end of the year.

The government is considering options that range from developing new engine technology all the way to building a new rocket to assure access to space for national security and other missions. Space hardware manufacturers are offering different advice on how to proceed that, predictability, matches their specialties.

Those differences were on display at a private event Aug. 21 during which industry representatives lined up to try and frame the debate for Pentagon and White House officials, according to sources who were in attendance.

The event, hosted by the Aerospace Industries Association, a trade group here, was held just hours after the U.S. Air Force released a formal request for information on options for rocket engines and commercially viable launch solutions.

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.

Frank Kendall, the Pentagon’s acquisition czar, addressed the RD-180 situation during a separate event held here Sept. 3.

“I think that there is close to a consensus of the administration that we need to find a way to remove the dependency,” Kendall said in a speech during the ComDef 2014 conference. “And we’re looking for the best course of action to do that.”

Industry and government sources say the AIA event, attended by about 50 industry representatives, offered a sneak preview of the discussions the Air Force will have with rocket hardware makers at an industry day Sept. 25-26.

Frank Slazer, vice president for space systems at AIA, declined to provide details of the closed session, saying only that it helped foster dialogue and put ideas on the table.

Sources said the meeting included representatives from most of the U.S. launch industry’s major players, including ULA, Space Exploration Technologies Corp., ATK, Orbital Sciences Corp., Blue Origin and Aerojet Rocketdyne.

Some of the companies, including Aerojet Rocketdyne, ATK, Blue Origin and to a lesser extent SpaceX, coalesced around the idea of developing a next-generation main-stage engine, sources said.

Aerojet Rocketdyne of Sacramento, California, the dominant U.S. supplier of large liquid-fueled rocket engines, is working on a kerosene-fueled, 500,000-pound-thrust concept dubbed AR-1, which the company has said could be fully developed in four years for less than $1 billion. In one scenario, sources said, two AR-1 engines would replace the RD-180 engine on the Atlas 5. The RD-180 generates nearly 900,000 pounds of thrust.

Representatives from Blue Origin, the Kent, Washington, firm bankrolled by Amazon.com founder Jeff Bezos, said the Air Force also should consider a liquid-oxygen/methane engine. Brooke Crawford, a spokeswoman for Blue Origin, declined to comment.

Officials from ATK Aerospace of Promontory, Utah, the largest U.S. supplier of solid-rocket motors, suggested the Air Force consider that as an alternative to the liquid-fueled engine envisioned by the service. The industrial base to produce a large, solid-fueled rocket is already in place, the company said, according to sources.

Jennifer Bowman, an ATK spokeswoman, said as a general practice the company does not disclose whether it has responded to business solicitations.

SpaceX of Hawthorne, California, could offer an engine as well. However, sources said SpaceX likely is more interested in simply offering the full-up Falcon 9 as a means of assured access to space. The Falcon 9 is currently being certified to carry military payloads, and SpaceX has a heavy-lift vehicle in development that is expected to debut next year.

SpaceX spokesman John Taylor declined to comment.

ULA announced in June it had signed “multiple” contracts with unidentified companies to study potential replacements for the RD-180, and hopes to select a single concept for development this year. Those companies will study hydrocarbon — meaning-kerosene or methane-fueled — engine concepts, and lay out schedules along with cost estimates and technical risks.

ULA officials, who frequently note that there has been no interruption in RD-180 deliveries since the Ukrainian crisis erupted, have said they will respond to the Air Force request for information but did not provide further details.

“There’s a wide range of things we could do,” Kendall said in his Sept. 3 speech. “Some of them are more straightforward than others.”

Responses to the Air Force request are due Sept. 19. Sources said they expect the Defense Department to make a decision on a path forward before the end of the year.