ATLANTA — Blue Origin announced Oct. 19 that it conducted the first successful test of its BE-4 engine, a major milestone for both the company's launch vehicle plans as well as for United Launch Alliance.

Blue Origin, in a tweet, said its first hotfire test of the BE-4 engine was a success. The company included a six-second video, taken from several angles, of the engine firing on a test stand, but provided no other information, including the date, duration or thrust level of the test. A Blue Origin spokesperson said the company was not releasing additional information about the test at this time.

"First hotfire of our BE-4 engine is a success," tweeted company founder Jeff Bezos. "Huge kudos to the whole @BlueOrigin team for this important step!"

The BE-4 is an engine that uses liquid oxygen and liquefied natural gas propellants and is capable of generating 550,000 pounds-force of thrust. The engine was developed in-house at Blue Origin primarily with its own funding, with some support from ULA.

Blue Origin plans to use the BE-4 on its New Glenn vehicle that the company announced last year. The first stage of the rocket will use seven BE-4 engines, with the second stage using a single BE-4. That rocket will be able to place up to 45 tons into low Earth orbit and 13 tons into geostationary transfer orbit.

The BE-4 is also under consideration by ULA for its next-generation Vulcan rocket. ULA is considering both the BE-4 and the AR1, a liquid oxygen and kerosene engine under development by Aerojet Rocketdyne, but has indicated that its preference is for the BE-4.

In an April interview, ULA Chief Executive Tory Bruno said that it was waiting for the outcome of an initial series of hotfire tests before formally selecting the BE-4. "The economic factors are largely in place now and the thing that is outstanding is the technical risk," he said then. "That's why we keep talking about the engine firing."

ULA spokesperson Jessica Rye said the company congratulated Blue Origin on the successful test, but gave no indication of when ULA might make a decision on the engine for Vulcan.

"Congratulations to the entire Blue Origin team on the successful hotfire of a full-scale BE-4 engine," she said in an Oct. 19 email. "This is a tremendous accomplishment in the development of a new engine."

At the time of the April interview, Blue Origin was expected to begin BE-4 engine tests in the coming weeks. However, in May the company reported it lost a set of powerpack hardware, a key component of the engine, during a test. At the time the company said it would be back in testing "soon" but offered few updates prior to the announcement of this test.

An independent assessment, conducted by NASA personnel and briefed to congressional staffers in June, concluded that the BE-4 retained a development lead of as much as two years over the AR1 despite the mishap. That briefing took place around the same time Blue Origin announced it will construct a factory in Huntsville, Alabama, to build BE-4 engines for both its own vehicles and for ULA, if it does select the BE-4 for Vulcan.

This story was provided by SpaceNews, dedicated to covering all aspects of the space industry.