The effort to develop a US alternative to the Russian-made RD-180 engine to provide assured access to space appears to be clouded by sharp differences among Air Force officials, space industry leaders, and a key lawmaker. In a Friday hearing before the House Armed Services Strategic Forces Subcommittee, five space industry leaders working to develop an RD-180 alternative all vowed that their engines would be available by 2019. But Air Force Space Command boss Gen. John Hyten and other officials said any of the new engines would require either a completely new space launch vehicle or major modifications to United Launch Alliance’s Atlas V rocket, which currently uses the RD-180. That would take additional years before the new launch system could be certified ready for national security launches, said Hyten and Lt. Gen. Samuel Greaves, commander of the Space and Missile Systems Center. “There is no drop-in replacement for the RD-180,” agreed Katrina McFarland, assistant defense secretary for acquisition. However, subcommittee Chairman Rep. Mike Rogers (R-Ala.) insisted that all Congress has authorized is a US-made engine to replace the RD-180 currently used in the Atlas V for heavy space payloads, not “a risky and expensive program to develop a new launch vehicle.” (Hyten prepared testimony.) (Greaves prepared testimony.)
The Air Force overall reduced its size by 120 aircraft in fiscal year 2021, but kept about the same number of fighter, bomber and attack aircraft, according to data supplied by the service. The F-35 fleet saw the biggest increase while the B-1B bomber fleet saw the largest decline.