WASHINGTON — A partnership between small launch vehicle company Firefly Aerospace and propulsion developer Aerojet Rocketdyne, highlighted by Firefly’s potential use of Aerojet’s AR1 engine, also has more immediate benefits for the companies.

Firefly and Aerojet announced a partnership Oct. 18 headlined by Firefly’s consideration of the AR1, an engine Aerojet originally developed for potential use by United Launch Alliance in its next-generation Vulcan vehicle, in Firefly’s Beta medium-class rocket.

However, at an Oct. 22 press conference held by the two companies during the 70th International Astronautical Congress here, the companies said the agreement goes beyond use of the AR1. That includes work to support development of Firefly’s Alpha launch vehicle slated to make its first flight in early 2020.

Tom Markusic, chief executive of Firefly, said one such area was in additive manufacturing to support production of the “head end” of the Reaver engine that powers the first stage of the Alpha rocket. That part of the engine “is a machined and welded structure” that is complex to build.

“Right now, Aerojet is helping us with that. They are printing the entire head end of the Reaver rocket engine,” he said. “That’s going to make it lighter weight, simpler, lower cost to build. As we speak today, parts are rolling out as part of this collaboration.”

Development of the Alpha first stage, with uses four Reaver engines, is ongoing. Markusic said the company is moving towards qualification tests of the stage, with all four engines, scheduled in mid-November. The company’s first orbital launch attempt is expected for February or March, he said, from Vandenberg Air Force Base in California.

Firefly is also considering in-space propulsion systems form Aerojet for an orbital transfer vehicle (OTV) the company is developing to enable satellites launched on Alpha to go to higher orbits. “Aerojet Rocketdyne has a whole corral of amazing in-space propulsion options,” Markusic said, including both chemical thrusters and Hall thrusters for electric propulsion. “That could be utilized on our OTV.”

However, the companies made clear that the centerpiece of the agreement was the potential use of the AR1 on Firefly’s Beta rocket, giving Aerojet a customer for the engine while allowing Firefly to increase the performance of the medium-class rocket.

Beta is intended to fill the niche once served by ULA’s Delta 2. “It has left an opportunity for a modern launcher to come in at perhaps a better price point than Delta 2, and can address some of the new missions coming out,” such as small geostationary orbit satellites, he said.

The target payload capacity of Beta is eight metric tons to low Earth orbit, a size Markusic explained was driven by the market and which, in turn, led to a design change for the rocket. Beta’s original design resembled the Alpha but with two additional first stages as side boosters, a triple-core design like the Delta 4 Heavy or Falcon Heavy. Beta is now a single-core vehicle with an AR1 engine in its first stage.

“We’ve been doing a lot of analysis of the medium-lift market in the intervening years, while we’ve been working on Alpha, and what we found is that we think the sweet spot is north of five metric tons,” he said. “Going with a triple-core Beta, which is based on Alpha technology alone, only gets us to about four metric tons.”

Beta is still at least a few years from flying. Markusic expects that once Alpha makes its first successful launch, Beta would be ready in two to three years. That timeframe keeps the company “laser-focused” on getting Alpha operational, he said, but also requires “drop-in” propulsion for Beta rather than new engine development.

Aerojet believes that it will have the AR1 ready to meet that timeframe. Jim Maser, senior vice president for space at Aerojet, said the company was currently assembling the first “test-ready” engine. “We anticipate having a test-ready engine put together in the first half of next year,” he said.

He added Aerojet would work with Firefly to determine when the AR1 would be needed for the Beta rocket, and pace the development of, and Aerojet’s investment in, the engine accordingly. “Right now we’re spending, actually, quite a bit of our own money on this, so we want to time that to be aligned to when we think the medium launch vehicle market is ready for this kind of engine,” he said.

One unresolved issue is whether Firefly will be the exclusive customer for the engine if the company selects it for Beta. “I don’t think we’d necessarily want to compete directly wherever Firefly is going, but we’ll just have to see where it plays out,” Maser said.

“From my perspective,” Markusic said, “increasing the volume of production will create economies of scale that will create cost savings. We’d like to see Aerojet make a lot of these engines.”

Jeff Foust writes about space policy, commercial space, and related topics for SpaceNews. He earned a Ph.D. in planetary sciences from the Massachusetts Institute of Technology and a bachelor’s degree with honors in geophysics and planetary science...