Incorporation of RD-180 Failure Response Features in the Atlas V Booster Emergency Detection System (2011)

Approximately 70% of the parts on the RD-180 engine as used on Atlas V launch vehicles are common with the RD-170 engine. The RD-170 engine was developed by NPO Energomash and certified in 1985 to power the Energia Buran rocket launch system, which was rated for human spaceflight as defined by the Russian standards. With over 45,000 seconds of operational time, the RD-180 has an extensive history of demonstrated performance, robustness, and reliability as does the Atlas vehicle that it powers. This paper describes why the RD-180/Atlas combination provides an optimal solution for human space flight directly applicable to the near-term commercial crew transportation program. The paper will examine how the RD-180/Atlas booster combination could meet Commercial Crew space flight requirements. An overview of the past NASA human space flight requirements to the Russian approach for manned flight will also be made. The paper will discuss the work that has been done to understand not only the potential failure modes to which the RD-180 propulsion system could be subjected to but also how these failure modes could be quickly identified, mitigated or managed such that a safe crew abort sequence could be initiated. The RD-180/Atlas Emergency Detection System (EDS) will be described and shown to be a viable approach to meeting Commercial Crew space flight requirements. This will include a discussion on the monitoring of key engine parameters that will provide early detection and notification to vehicle computers to verify the onset of the failure and enable rapid response. An explanation as to why the RD-180 offers an affordable solution to Commercial Crew transportation will be presented. Areas requiring further work will also be discussed. I. Atlas/RD-180 Background and Future Plans for Space The RD-180 liquid-propellant rocket engine provides boost phase thrust for United Launch Alliance's (ULA) Atlas V launch vehicle (see Figure 1). Additionally, the RD-180 was the propulsion choice for all Atlas III launch vehicles. Providing nearly one million pounds of thrust, the RD-180, is the highest performing state of the art kerosene-fueled booster engine in the world. Pratt & Whitney Rocketdyne (PWR) and NPO Energomash (NPO-EM), working together under cooperative agreements, have provided reliable, low-cost propulsion to the U.S. Atlas vehicle manufacturer for more than sixteen years. Through Pratt & Whitney’s and United Technologies Corporation’s financial investment, the RD-180 was designed, development tested, and flight qualified initially for the evolutionary Atlas III launch vehicle. This cooperative effort was further reinforced by the formation of a joint venture (JV) between the two companies known as RD AMROSS, which is the sole distributor of the RD-180 engine in the U.S. Through RD AMROSS, a PWR and NPO-EM JV company, the RD-180 engine has been certified for the more demanding thrust profiles of the Atlas V vehicle. RD-180s have successfully powered thirty-three (33) Atlas launch vehicles; including twenty-seven Atlas Vs with a 100% mission success record.