In June, the US Government Accountability Office released a report on NASA's Commercial Crew Program that noted a deviation related to an engine that occurred during the launch of the Atlas V rocket in 2018. Particular focus was placed on this issue, as the Atlas V is planned to be used for launches of US Starliner spacecraft to the International Space Station. The report, however, did not disclose the name of the engine.
"Yes. The RD-180 engine is a successful and reliable engine and has flown 79 times with 100% mission success," Armold said, answering a question on whether RD-180 was the engine in question.
According to Arnold, during the launch, engine's position slightly deviated from the one that was set by a control system, however, it did not affect the launch, and the payload of the rocket was placed into a proper orbit.
"Rocket launches are extremely intricate and include processes where hundreds of technical interfaces must work correctly at the same time. During a 2018 launch, the engine deviated slightly from command during ascent, and though not desirable, did not impact the mission performance. The mission was a complete success and the payload reached the intended orbit," Arnold said.
At the same time, Arnold did not specify during which launch the deviation took place, as there were five Atlas V launches in 2018.
RD-180 is developed and manufactured by NPO Energomash, a major Russian rocket engine manufacturer, and is designed for the use in US Atlas carrier rockets.
In order to lower Washington's reliance on Russian engines, the US Congress had attempted to strictly limit future purchases of RD-180 as part of economic sanctions against Moscow, with a law requiring the United States to develop a domestically produced next-generation rocket propulsion system by 2019 having been passed. However, in 2015, the ban was cancelled and the following year, the US Senate decided to continue purchasing Russian RD-180 rocket engines for launches into space.