"Right now we are on track… to complete the transition period [and] come out the back end with two domestic service providers," Goldfein said when asked for an update on transitioning from the RD-180 rocket engine.
Golfdein said the Air Force was also on schedule to ensure access to all the orbitology for any platform put into low or high or geosynchronous orbit.
In January, US launch vehicle Atlas V with satellite GEO-4 was launched from Cape Canaveral. The first stage powered by RD-180 engine successfully separated.
In 2014, US Congress passed a law mandating that the United States phase out its reliance on the RD-180 engines.