COLORADO SPRINGS, Colo. – United Launch Alliance’s president and CEO, Tory Bruno, is facing a 2019 deadline from Congress to come up with a made-in-the-USA replacement for the Russian-built rocket engines currently used on ULA’s workhorse Atlas 5 launch vehicle. But he doesn’t sound worried. He’s got a Plan A, and a Plan B.

“We’re in that great position of having the two to choose from,” Bruno told GeekWire this week here at the 32nd Space Symposium.

Plan A is a rocket engine that’s being built by Blue Origin, the company founded by Amazon billionaire Jeff Bezos and headquartered in Kent, Wash. Nineteen months ago, Bezos and Bruno announced a deal to support the development of Blue Origin’s BE-4 engine, fueled by liquid natural gas, for ULA’s next-generation Vulcan semi-reusable rocket.

Bruno said Bezos is putting up the “lion’s share” of the money for the effort, and in February, the U.S. Air Force provided an additional $46.6 million boost.

But then there’s Plan B: Aerojet Rocketdyne – which is based in Sacramento, Calif., but has a facility in Redmond, Wash. – is getting $115 million from the Air Force to develop a kerosene-fueled engine called the AR-1 that could serve as an alternative for ULA’s rockets.

United Launch Alliance, a Colorado-based joint venture involving the Boeing Co. and Lockheed Martin, will soon have to pick which plan to go with. It’s not a decision Bruno takes lightly.

“Billions are at stake,” he said. “The nation’s ability to maintain its edge in space for national security is at stake.”

Both companies say they’re the best match for ULA.

“All of us at Blue Origin find the fact that we are going to get to help with the national security missions incredibly motivating,” Bezos said at the Space Symposium.

Eileen Drake, Aerojet’s CEO and president, was similarly bullish: “In developing our AR-1 engine, we have specifically chosen a very proven propellant, a proven engine cycle and a proven design methodology to make sure that we minimize any risk to mission and to schedule.”

By some measures, Blue Origin is taking the riskier approach: The 550,000-pound-thrust BE-4 would be the biggest methane-fueled rocket engine ever built.

“Jeff is the one that has to demonstrate that his technical risk is retired,” Bruno said.

But Blue Origin got a head start on its project, because it had already been working on the BE-4 for its own future orbital rocket for three years when the ULA deal was struck. “We expect that if Jeff succeeds, he will be done first, because he started first,” Bruno said. “He’ll be delivering an engine to us, based on both of their respective schedules, about 16 months earlier.”

That’s assuming the BE-4 works. The turning point will come when Blue Origin operates the full-scale engine for an extended period of time in ground tests – a major milestone that’s expected to take place by the end of the year.

If those tests are successful, ULA will assess the projected schedule for delivering engines, as well as their expected performance and cost, and “down-select” to either Plan A or Plan B for the Vulcan rocket, Bruno said.

That decision will mark a turning point for ULA as well as for Blue Origin and Aerojet. ULA is no longer the only game in town when it comes to putting U.S. national security payloads into orbit. Last year, Elon Musk’s SpaceX launch venture was certified to fly such payloads as well. And this year, SpaceX and Orbital ATK received separate awards from the Air Force for rocket propulsion projects.

The competitive environment is forcing ULA into a “big transformation,” Bruno said.

This week, he announced that up to 875 job positions, representing about 25 percent of ULA’s current workforce, would be eliminated by the end of 2017 to make the company more competitive with SpaceX. A big part of the rationale is that ULA would be dropping its Delta line of launch vehicles and making the transition from Atlas to Vulcan.

One of the selling points for Aerojet has been that the kerosene-fueled AR-1 could serve as a direct replacement for the Russian-made RD-180 engine on the Atlas 5. But Bruno said that’s not the case. For one thing, it’d take two 550,000-pound-thrust AR-1 engines to fill in for the 860,000-pound-thrust RD-180. “There really is no drop-in replacement,” he said.

Bruno expects that the Atlas 5’s customers will switch to the more powerful, less expensive Vulcan once it enters service. Those customers include national security agencies and commercial satellite ventures as well as Boeing, which plans to use the Atlas 5 to send its CST-100 Starliner space taxi to the International Space Station.

Although the rocket engine race is the biggest decision facing ULA in the months ahead, Bruno is also casting his eye to farther frontiers. For example, ULA and Bigelow Aerospace announced a partnership this week that could put Bigelow’s B330 expandable space module into Earth orbit in 2020, potentially to serve as a commercial space lab.

ULA is also working on an upper-stage rocket propulsion system known as the Advanced Cryogenic Evolved Stage, or ACES. The hydrogen-fueled system could make use of Aerojet’s enhanced RL-10 rocket engine, Blue Origin’s BE-3 engine, or XCOR Aerospace’s 8H21 engine. It’s designed to provide much more capability than ULA’s current Centaur upper stage.

Within a couple of decades, we see 1,000 men and women in space – because their jobs are in space.

Bruno noted that the Centaur was designed to operate in the seven to eight hours after launch. “ACES will not go for seven or eight hours,” he said. “It will go for seven or eight days.”

ACES could serve as an element for in-space transportation, opening the way for more people to live and work in space. “I think that we’re just really on the very threshold of expanding the permanent human presence beyond our planet,” Bruno said.

A ULA initiative known as #Cislunar1000 is aimed at laying out a long-term vision for taking advantage of resources such as near-Earth asteroids, lunar ice and space solar power. The objective? To build up a self-sustaining economic base in the region of space around Earth and the moon.

“It’s very different from the exploration mission that we’ve done all this time, led by NASA,” Bruno said. “That’s great work, but now Lewis and Clark have come and gone, and it’s time to come behind with the farms and the homesteads. Eventually, within a couple of decades, we see 1,000 men and women in space – because their jobs are in space.”

Sounds like Elon Musk is no longer the only space executive talking about turning humanity into a multiplanetary species.