Orbital Sciences chooses RD-181 as AJ-26 engine replacement
Orbital Sciences Corporation (Orbital ) has confirmed that it will replace the engines powering its Antares rocket, the AJ-26, with RD-181 engines supplied by Russia’s NPO Energomash. While other U.S.-based launch service providers are moving away from Russian-made rocket engines, Orbital has made the decision to move from one Russian-made engine to another.
Orbital had previously indicated that the AJ-26 would be replaced, but had not yet revealed the identity of the replacement engine.
Aviation Week first reported, on Dec. 16, that Orbital had chosen the RD-181. Later in the day, on Twitter, Orbital confirmed the information provided in the Aviation Week article and stated that the: “RD-181 engine meets schedule and technical requirements. No other options do . . . . [The] RD-181 is [the] only propulsion option that enables us to complete cargo commitments to @NASA under [the] #CRS contract by [the] end of 2016.”
According to Aviation Week, the RD-181 is a “descendant of the RD-171 that powers the Ukrainian-built Zenit launch vehicle [and] . . . . will be manufactured in the same Khimki factory that builds the RD-180 used on the United Launch Alliance [(ULA)] Atlas V. It closely resembles the RD-191 on Russia’s new Angara launcher and the RD-151 that powers South Korea’s Naro-1 launch vehicle.”
Orbital expects that “[f]irst deliveries of the newly built #RD-181 engines is mid-2015 to be ready for [the] next #Antares flight in early 2016.” Until that time, Orbital has purchased at least one ULA Atlas V rocket to launch its Cygnus spacecraft to the International Space Station (ISS) in order to meet the requirements under its $1.9 billion Commercial Resupply Services contract with NASA.
As has been previously reported, Orbital’s Antares rocket recently suffered a catastrophic launch failure – exploding and falling back onto its launch pad at NASA’s Wallops Flight Facility in Virginia.
Two AJ-26 engines powered the first stage of the Antares rocket and, even though the launch failure is still under investigation, Orbital has stated that the likely cause of the disaster was a turbopump located in one of the two engines.
The AJ-26 has a less than perfect history. In addition to the recent launch failure, the engine has suffered at least two relatively recent test failures.
In June 2011, an AJ-26 caught fire, and failed, in a test stand at NASA’s Stennis Space Center (SSC) in Mississippi, due to a fuel leak resulting from “stress corrosion cracking of the 40-year old metal.”
In addition, on May 22 of this year, another AJ-26 failed, in the same SSC test stand, approximately 30 seconds into a scheduled 54 second test.
Scott earned both a Bachelor's Degree in public administration, and a law degree, from Samford University in Birmingham, Alabama. He currently practices law in the Birmingham suburb of Homewood. Scott first remembers visiting Marshall Space Flight Center in 1978 to get an up-close look at the first orbiter, Enterprise, which had been transported to Huntsville for dynamic testing. More recently, in 2006, he participated in an effort at the United States Space and Rocket Center (USSRC) to restore the long-neglected Skylab 1-G Trainer. This led to a volunteer position, with the USSRC curator, where he worked for several years maintaining exhibits and archival material, including flown space hardware. Scott attended the STS - 110, 116 and 135 shuttle launches, along with Ares I-X, Atlas V MSL and Delta IV NROL-15 launches. More recently, he covered the Atlas V SBIRS GEO-2 and MAVEN launches, along with the Antares ORB-1, SpaceX CRS-3, and Orion EFT-1 launches.