Main Engine Cut Off

Blue Origin Switches to BE-3U for New Glenn Second Stage

A Blue Origin executive told SpaceNews the company is shelving development of a vacuum-optimized version of BE-4 and will instead use vacuum-optimized versions of flight-proven BE-3 engines for New Glenn’s second stage and optional third stage.

“We’ve already flown BE-3s, and we were already in the development program for BE-3U as the third stage for New Glenn,” said Clay Mowry, Blue Origin’s vice president of sales, marketing and customer experience. “It made a lot of sense for us to switch to an architecture where we get there faster for first flight.”

Mowry said switching to the BE-3U for New Glenn’s second stage will allow Blue Origin to conduct the rocket’s first launch in the fourth quarter of 2020. He declined to say how much time the engine change saves compared to the original configuration.

Moving from a methalox stage with a single BE-4U to a hydrolox stage powered by two BE-3U engines means a longer, lighter stage with better efficiency. The last I heard, BE-3U was projected to put out 150,000 pounds of thrust in vacuum, so with lighter propellant, the thrust-to-weight is still reasonable and BE-3U’s better specific impulse brings big benefits once on orbit.

Maybe the change was brought about by the seemingly-slower ramp up of BE-4 testing, but nonetheless it gets them to the pad quicker, simplifies their production lines and operations, and allows them to hit just about every useful flight profile from day one:

Blue Origin is lining up New Glenn to compete with United Launch Alliance and SpaceX in launching U.S. military satellites by giving the rocket enough muscle to reach every orbit specified in the Launch Service Agreement (LSA) solicitation the U.S. Air Force issued last fall. The solicitation — which has also drawn interest from Orbital ATK and Aerojet Rocketdyne — specifies nine wide-ranging “reference orbits” the proposed launchers must be able to reach in order to qualify for Air Force funding.

The Air Force plans to help fund development of at least three launch system prototypes. Awards are expected in July.

“If you look at LSA and all those mission profiles, we can serve all of those with a single version of New Glenn with this two-stage architecture,” Mowry said.

There are some lingering questions about what this does to New Glenn’s payload capacity and how it may affect its flight profile with regards to first stage recovery, but overall I think this is a great move from Blue Origin.

I’m still thinking things through, so you’ll hear more from me on this topic soon, but it also has really interesting implications for their future projects.