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USA's efforts to stop relying on Russian-built rocket engines derailed by issues with Blue Origin's BE-4

Government Accountability Office warns of build-your-own-booster delays

Updated Things aren't looking too good for a certain American-produced rocket engine, according to the US Government Accountability Office - and it isn't SpaceX's Merlin.

The June GAO Weapon Systems Annual Assessment report to Congress [PDF] makes grim reading for fans of billionaire-built space stuff. Noted by NASAWatch, the section of the report concerning the National Security Space Launch (NSSL) was clear about the challenges faced by a "US-produced rocket engine under development for ULA's Vulcan launch vehicle."

What engine could that be?

ULA's Vulcan Centaur, self-described as "America's Rocket" and slated to replace the existing Atlas V for NSSL payloads, is powered by a variety of engines. Up to six Northrop Grumman Graphite Epoxy Motor (GEM) 63XL Solid Rocket Boosters (SRBs) can be strapped to the first stage and the second stage uses a pair of workhorse RL10C engines (which have been used on nearly 400 successful flights).

The first stage, however, is also due to be powered by a pair of BE-4 engines, manufactured by Jeff Bezos' Blue Origin. These have yet to see action on the way to orbit. As well as ULA's new launcher, the engines also power Blue Origin's New Glenn, the maiden flight of which has been punted to the end of 2022.

The GAO report noted the "technical challenges" were related to "the igniter and booster capabilities required" and that there was a risk of qualification not being complete in time. The result could be a switch back to trusty Atlas V, which carries its own problems.

The first stage of the Atlas V is powered by RD-180 engines, manufactured in the Russian Federation. The NSSL's goal is to remove this reliance, although an amendment permits the use of 18 more engines for contracts awarded through 2022. The Vulcan Centaur and its BE-4-engined first stage is ULA's primary solution to the problem. Time, however, is getting a bit tight.

As for SpaceX, its Falcon 9 and Falcon Heavy rockets are certified for national security launches, although the GAO noted that the Heavy had been "on track to support its first [national security] mission in May 2021."

The Register asked Blue Origin and ULA for their take on the report and will update should either respond. ®

Updated at 09:55 UTC on 23 June 2021 to add:

ULA told The Reg it "appreciates the GAO in overseeing government programs," going on to add:

The law states DOD must order their last Atlas V by the end of 2022. ULA has already received delivery of the last RD-180 engines anticipated, and they are safely stored in our factory in Decatur, Alabama, so this will not be a concern as we transition to our new Vulcan launch vehicle.

With the importance of space to the protection of the nation and usage in our daily lives from communication and navigation, it is essential we mitigate any delays in the nation’s access to space. To mitigate any delays in Vulcan engine deliveries from our supplier, ULA is taking many steps including advanced manufacturing techniques, such as additive, which enable a faster development, as well as maintaining our schedule by sending rocket flight articles to the launch site for test and fit checks.

The spacecraft launch service provider added: "Development programs are difficult, but Vulcan is proceeding very well and we will not come close to using all of the 18 RD-180 engines for National Security Space missions that are allowed under the law. We are committed to a smooth and reliable transition from Atlas to Vulcan to meet challenging space launch demands."

It did not mention the BE-4 engines.

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