THE RD-180 ENGINE

With state orders for RD-170 and RD-171 engines running out, NPO Energomash began looking at international marketing opportunities for its engines in the early 1990s, setting its sights on America in particular. Realizing that the RD-170/171 thrust levels were beyond what was needed on American launch vehicles, the com­pany designed a two-chamber version of the engine called RD-180 that was tailored to the US market and was probably similar to a first-stage engine studied for the 11K55. In October 1992 Pratt & Whitney started working with Energomash to draw American customers to the RD-180 and a tripropellant engine known as the RD-701, and also to advise the Russian company on ways to implement a cost-accounting system [71]. The RD-180 was considered for use on a new two-stage Martin Marietta booster as well as an upgraded version of General Dynamics’ Atlas-II rocket [72].

In 1994 General Dynamics Space Systems was sold to Martin Marietta, which in turn merged with Lockheed in 1995 to become Lockheed Martin. The company continued looking at new engines to power its new Atlas-IIAR rocket (later renamed Atlas III) as well as a new generation of Atlas vehicles (Atlas V) being developed under the Air Porce’s Evolved Expendable Launch Vehicle (EELV) competition. In January 1996 Lockheed Martin’s choice fell on the RD-180, which beat the Aerojet – sponsored NK-33, a Russian engine originally developed for the N-1 Moon rocket,

and a derivative of Rocketdyne’s venerable MA-5A called the MA-5D. Just one nozzle of the RD-180 generates as much thrust as all three MA-5A nozzles combined on the older Atlas configuration.

The RD-180 essentially is an RD-170 “cut in half” with a new, less powerful turbopump driven by a single gas generator. About 75 percent of parts are identical to those of the RD-170. It has a sea-level thrust of 390 tons and a specific impulse of 311 s. The engine has several features that made it attractive to Lockheed Martin. It operates at much higher pressures than most other expendable booster engines, allowing the deep throttling capacity critical to effective engine use. The RD-180 can throttle over a 40-100 percent range, yet it remains flat in specific impulse throughout this range (losing just about a second of Isp), which is very important to fly the engine on both light and heavy-lift launch vehicles. The RD-180’s single-shaft turbine, liquid-oxygen pump, and single-stage propellant pump are all on one shaft, which cuts overall parts count, reduces cost, and translates to excellent reliability. Further­more, adoption of Russian seal and flange technologies virtually eliminated cryogenic system leaks that were accepted as normal on US boosters.

In early 1997 Energomash and Pratt & Whitney expanded their cooperation on the RD-180 into a joint venture called RD Amross LCC to build and market the engine. At the time the RD-180 accounted for 75 percent of Energomash’s business. In June 1997 Lockheed Martin announced it would purchase 101 RD-180 engines from Amross under a contract expected to be worth 1 billion dollars. In a move to allay concerns about relying on Russian technology for placing military and intelli­gence satellites into orbit, Lockheed Martin vowed that the US would set up its own production line at a new Pratt & Whitney facility in West Palm Beach, Florida, but those plans have run into numerous delays.

A prototype version of the RD-180 underwent an initial test firing at Energo­mash’s test facilities in Khimki in November 1996. The first test firing of a full-fledged engine followed in April 1997. Also applicable to the RD-180 were test firings of the RD-173, which had several new features that were incorporated into the RD-180. An RD-180 mated to an Atlas III thrust structure and tank simulator was first test-fired at the Marshall Space Flight Center in Huntsville, Alabama in July 1998. The Atlas III debuted in a spectacular launch from Cape Canaveral on 24 May 2000, success­fully placing into orbit a Eutelsat communications satellite. It was a landmark event in US-Russian space cooperation, very illustrative of the new, post Cold War atmo­sphere. A US rocket that had evolved from an ICBM conceived to level Soviet cities was now powered by a Russian rocket engine that itself had its origins in a program once seen as a crucial part of the military space race.

The Atlas III was retired in 2005 after seven successful missions, clearing the way for the new Atlas V generation. In November 1997 the Air Force had decided to modify its procurement plans for the EELV program, splitting the work between a pair of finalists rather than going for a single winner-take-all award. One of the major reasons given for the redirection was to enhance US space launch competitiveness by keeping two rocket builders in business. The work would now be divided between Lockheed Martin with its Atlas V family and McDonnell Douglas (later Boeing) with its Delta-4 family.

The Atlas V family uses a Common Core Booster (CCB) first stage fitted with an RD-180 engine and flanked by up to five solid rocket boosters. The Centaur second stage is powered by either a single or two RLA-10A-4-2 engines and the payload is protected by either a 4 or 5 m diameter payload fairing. There were also plans for an

Atlas V Heavy featuring three CCBs coupled together, but Lockheed Martin is no longer actively pursuing development of this version.

Given the slightly different flight modes for the medium-lift and heavy-lift Atlas V versions, the RD-180 had to undergo separate certification programs for the two versions, although it is exactly the same engine as flown on the Atlas III. The impressive RD-180 test-firing program was completed in early 2002. Since the first test in 1996, the RD-180 averaged a full flight duration firing every 10 days, encom­passing 135 total development and certification tests in Khimki, comprised of 91 Atlas III class tests, 30 Atlas V Medium class tests, and 14 Atlas V Heavy class tests. All totaled, the RD-180 racked up an impressive 25,449 seconds of development and certification test firing in Khimki alone, equivalent to 110 nominal Atlas V missions. The inaugural flight of the Atlas V took place on 21 August 2002. The RD-180 may also fly on the first stage of a Japanese rocket called Galaxy Express, which is expected to use the first stage of the Atlas III [73].