ATK has provided additional details about its domestic alternative to the Russian-built RD-180 engine currently in use on the venerable Atlas V rocket of United Launch Alliance (ULA). While ULA has aligned with Blue Origin’s BE-4 engine, ATK proposal of a solid-fueled first stage – as a reliable, cost-effective, and commercial alternative to the RD-180 – provides insight into the wealth of American-built engine options.
The Atlas V rocket:
Since its maiden flight on 21 August 2002, the Atlas V rocket has quickly risen to the top of the U.S. commercial launch system and is routinely called upon for commercial and government launches, missions of national security, and short-launch-window interplanetary missions for NASA.
Having conducted 49 flights to date, every single mission of the Atlas V has either been a complete success or been deemed to be a success by the payload customer.
Thus, the Atlas V rocket is the current, most-reliable vehicle in the U.S. rocket fleet.
Utilizing the Atlas Common Core Booster (CCB), the first stage operates across all variants of the Atlas V with a single engine, dual nozzle RD-180 engine built by the RD AMROSS company.
The RD-180 has provided exceptional performance to the Atlas V and was chosen to be the engine of the first stage in no small part because of its safety record and reliable performance track record.
During first stage flight, the RD-180 engine burns a mixture of kerosene and liquid oxygen.
This has been the unchanged configuration of the Atlas V for 12 years.
However, the RD-180 is built by RD AMROSS, a U.S. joint venture of Pratt & Whitney Rocketdyne located in West Palm Beach, Florida, and NPO Energomash of Khimki, Russia.
Under the original joint-venture contract, Energomash was contracted to deliver 101 RD-180 engines, enough for 101 missions of the Atlas V, for the fixed price of $1 billion USD.
Originally, Pratt & Whitney were licensed to produce the RD-180 engine domestically beginning in 2008.
Eventually, that date moved to 2012 and is now considered unfeasible due to a new understanding that it would cost an additional $1 billion USD and five years to begin producing the engine in the U.S.
At this point, it was agreed to continue importing the engine from Russia.
However, due to the various geopolitical and U.S. political considerations that have come to the fore in 2014, the SpaceX corporation filed a complaint in U.S. Federal court in April 2014 stating that the continued import of the RD-180 engine from Russia would violate the newly-imposed U.S. sanctions against Russia.
The U.S. Federal Court of Appeals agreed with the complaint and ordered an injunction on the engine’s import.
Following this decision, United Launch Alliance (ULA) began considering a replacement for the RD-180 engine on the first stage of the Atlas V.
Specifically, ULA began looking for a domestically produced engine alternative to the RD-180, one that would not be subject to various geopolitical tensions.
The formal study contracts for this initiative were issued by ULA in June 2014 to a select group of United States rocket engine suppliers.
By September 2014, United launch alliance had entered into a contract with Blue origin to develop the BE-4 LOX/methane engine as the replacement for the RD-180.
Under the terms of the development contract, Blue Origin will complete development of the BE-4 engine for use on the Atlas V rocket beginning no earlier than 2019.
Two BE-4 engines, each producing 550,000 lbf thrust at lift-off will be necessary on the Atlas V rocket’s first stage.
ULA currently has enough RD-180 engines in stock, already imported from Russia, to meet the Atlas V rocket launch schedule and demand until the BE-4 engines can enter service.
ATK’s solid fuel first stage alternative:
Nevertheless, while ULA has entered into contract with the Blue Origin company, ATK has announced their plan to offer a solid fuel first stage alternative for the RD-180 engine of the Atlas V.
Initial information came via the Request For Information (RFI) as part of the first step toward the Air Force funding alternative propulsion solutions to the RD-180.
According to a press release from late September, “ATK’s solid rocket propulsion solution provides a cost-effective, reliable solution based on advanced technology,” said Blake Larson, President of ATK’s Aerospace Group.
For ATK, the development of new technologies in the previous years has led to innovative design improvements with solid rocket motors, resulting in higher performance and increased reliability and affordability.
According to Larson, “By combining our extensive experience with new technologies, we have provided commercial customers with low-cost solutions that progressed from design to flight qualification within months.”
By using a similar approach as those used in the past, ATK would be able to provide a solid fuel alternative to the RD-180 engine by the deadline of 2019 as set by United Launch Alliance.
According to ATK, manufacturing and testing of the solid fueled solution for the RD-180 replacement would take place within the United States using tooling and infrastructure already in place across the country.
In a response to NASASpaceflight.com regarding this initial release of information, ATK added that testing on the RD-180 solid fueled boost phase replacement would take place in addition to, not in replacement of, the various other commercial, civil, and government contracts ATK is already responsible for fulfilling.
In fact, ATK further stated that adding the RD-180 replacement to ATK’s roster would fit within the existing scope and capabilities of the company.
Over the last seven years, ATK noted that they have designed six new motors that have all provided insight into increasing efficiency in the motor development and implementation process.
A prime example noted by the company is the CASTOR 30 XL program for the Antares rocket for commercial resupply efforts with the International Space Station.
In the case of CASTOR 30 XL, ATK noted that they successfully developed and tested the motor in 22 months.
This type of development process would be used for the RD-180 solid propellant replacement solution.
Additionally, the solid fueled boost phase replacement option for the Atlas V rocket could be designed by ATK in such a way as to maintain the current height of the Atlas V, thereby maintaining most of the current pad infrastructure for the rocket without radical redesign.
The solid fueled first stage could also be designed to specifically meet the Atlas V launch vehicle and payload requirements, including the upcoming requirement to ferry crew aboard Boeing’s CST-100 capsule.
Application of ATK first stage for Antares:
At the same time that ATK submitted its proposal for the U.S. Air Force, the company also put forward – as part of a request from Orbital Sciences Corporation – a proposal for a solid-fueled, domestically-produced first stage for Orbital’s Antares rocket.
The proposal stemmed from Orbital Sciences’ plan to perform an Antares propulsion system upgrade. This upgrade would change the first stage engines of Antares away from the decades-old AJ-26 engines used on the opening Antares core stage variant.
Currently, Antares’ first stage uses two Soviet-built NK-33 engines modified by Aerojet Rocketdyne into the AJ-26 engines.
These engines successfully lofted a test Antares vehicle in April 2013, a Cygnus demonstration flight in September 2013, and the first two ISS resupply missions of Cygnus in January and June 2014.
Following these four missions, Antares’ third Cygnus resupply mission (CRS Orb-3) – the fifth overall flight of Antares – experienced a mission-ending engine failure 15 seconds after liftoff.
This failure has put added need to accelerating the Antares propulsion system upgrade.
In a statement released by Orbital, the company said that they were looking to introduce the new upgraded Antares propulsion system by 2016.
Although Orbital won’t be drawn on what engine will release the AJ-26 – which is now under a stop work order, per L2 information – the company might be leaning toward Russian-built RD-193 (known as the RD-181 once exported) engine as the replacement for the AJ-26 engines.
That leaning might be complicated by the current geopolitical situation between the United States and Russia.
As such, a domestic engine alternative might be in consideration for Antares.
If a domestic engine alternative is pursued, however, ATK’s proposal to provide a solid-fueled first stage for Antares would provide an almost-completely solid-fueled system for Antares. ATK already manufactures Antares’ upper stage, the CASTOR-30XL.
Regardless of whether or not Orbital accepts and proceeds with ATK’s option for Antares’s first stage, ATK’s proposal furthers the company’s commitment toward providing domestic, reliable, solid-fueled motors for America’s spaceflight programs.
(Images: via ULA, NASA, ATK, NPO Energomash and L2).
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