WASHINGTON — Rocket Lab passed a milestone in the production of its Electron rocket as the company gears up for its next launch and continues work on a new launch facility.

The company announced in early July that it had now manufactured 100 of its Rutherford engines that power the Electron rocket. Nine Rutherford engines are in the rocket’s first stage, and a one vacuum-optimized engine is in its second stage.

The Rutherford engine, which uses liquid oxygen and kerosene propellants, produces 5,500 pounds-force of thrust. Rocket Lab makes extensive use of additive manufacturing to produce the engine’s major components, including its combustion chamber, injectors and pumps, and the engine uses an electric turbopump.

The design of the engine has changed little since production started, said Peter Beck, chief executive of Rocket Lab, in a recent interview. “We designed the engine from day one to be high performance and mass producible,” he said. “If you take engine 1 versus engine 100, they really don’t look any different.”

Beck said the company came up with a stable design of the engine and then focused on ramping up production. “The design of the engine was really centralized around manufacturability,” he said. “We planned on producing a lot of these engines, so we planned processes and designs that were very scalable.”

That approach will allow Rocket Lab to further increase production to accommodate a higher flight rate. The company expects to produce 200 Rutherford engines over the next year at an expanded facility in Huntington Beach, California.

“We just keep buying more and more 3D printers and just keep producing more and more engines,” Beck said. He added that the company is putting a lot of effort into automating the testing and checkout process of the engines, which includes a 20-second test fire and full-duration burn.

Seventy of the 100 engines Rocket Lab has produced to date have been flown on seven Electron launches. The eighth Electron launch is scheduled for early August, Beck said, with the rocket just transported from its factory to Launch Complex 1 on New Zealand’s Mahia Peninsula.

The launch will be similar to the previous Electron mission June 29, carrying a BlackSky imaging satellite and a number of secondary payloads, he said. The specific payload manifest will be announced closer to launch.

“This puts us on a one-a-month stride that we’ve been trying to maintain for the last few flights,” Beck said. Rocket Lab is planning to double the rate of vehicle production over the next several months, to one vehicle every two weeks, although Beck said that won’t immediately translate into a higher launch rate.

As Rocket Lab scales up production, it is also building a second launch pad, Launch Complex 2, at the Mid-Atlantic Regional Spaceport on Wallops Island, Virginia. That construction is going well, he said, with the facility — which includes both the pad itself as well as an integration facility and mission control center — on track to be completed by the end of the year.

While the company had previously talked about carrying a first launch from Wallops this year, Beck said it’s more likely to take place in early next year. “There is a strong business case for us to build that facility,” he said. “We’re seeing a lot of interest, especially from government customers.”