Liberty launch team grows as Lockheed Martin joins ATK and Astrium
Three months after made its first-ever call for “full-up, end-to-end integrated system” proposals for its commercial crew program, contenders are revealing complete concepts and new teammates.
At stake is not only a share of the action with multiple Space Act agreements on offer worth up to $500 million, but a potentially priceless lead role in commercial space access for decades to come. Vying for such a place is Alliant Techsystems (ATK), which has announced plans to develop a composite crew compartment with support fromas part of a complete launch system being proposed with Astrium. Other contenders include Blue Origin, , (SpaceX) and Sierra Nevada.
Unveiling new details about its Liberty project, ATK says the system could be tested in 2014, with the first crewed test mission anticipated as early as 2015. Kent Rominger, ATK vice president and Liberty program manager, says the test plan supports crewed missions forby 2016 and is built on flight-proven elements.
“We're at the point where [the U.S.'s] reputation is on the line, and hopefully when people see Liberty they'll recognize the whole system is unique in that it has been designed from the outset to meet NASA's human-rated standards,” says Rominger. Although ATK and Astrium previously detailed the use of a five-segment, space shuttle-derived solid first stage and Ariane 5-based liquid-fueled upper stage for Liberty's combined configuration, the team has not previously discussed details of the crew capsule, abort system and other elements of its proposal.
Liberty is one of several competing system-level proposals for the third phase of NASA's commercial crew program, known as Commercial Crew Integrated Capability (CCiCap). Proposals for the contest were submitted in March, with expectations of multiple follow-on contracts valued at $300-500 million due to be awarded in early August.
“Unlike when we bid on CCDev2 [Commercial Crew Development 2], now we have an entire system,” says Rominger. The spacecraft leverages design work performed atResearch Center on the composite crew module and Maximum Launch Abort System (MLAS), for which ATK was a contractor, as well as service module design work performed by NASA Glenn Research Center, he adds. “We're using all that work and, in some cases, making it less capable to suit the less demanding missions to low Earth orbit [LEO].”
ATK's crew module development comes as the manufacturer's aerospace structures division continues the company's strategic push for leadership in composite assembly for commercial, military and space markets. As well as wing skins and access covers for theJoint Strike Fighter, ATK produces stringers and frames for the majority of the fuselage in addition to engine cases for the -8 and A350. Composite structures for space applications include large elements of the Delta IV, Atlas V, Ariane 5 and more than 11,100 rocket motor cases.
Aside from the better strength-to-weight ratio of composites over metal, ATK decided to pursue the advanced design for the crew module because “it's a core competency, so it makes sense,” says Rominger. However, to allay concerns over the potential permeability of the material in the vacuum of space, tests are underway to check that the composite capsule does not leak. “As we speak, the composite crew module is undergoing permeability tests at NASA Langley. Even without a coating, it meets requirements for being docked at the International Space Station for up to 210 days,” says Rominger. “There are a lot of skeptics about composites, but we're comfortable with them.”
The abort system is a pusher rather than a tractor device; but unlike liquid-fueled pusher abort systems proposed for competing designs such as the Boeing CST-100, the Liberty system will have six solid rocket motors embedded around the periphery of the crew vehicle. “It's very capable and very simple,” says Rominger. “If you had a fire, it will take the crew over a mile from the pad.”
ATK considered a liquid-fueled system, which would have enabled the potential use of unexpended propellant in orbit. However, it finally opted for solids because of simplicity and the fact that the additional thrust “is not that significant” on a vehicle designed to deliver 44,000 lb. into orbit. The solid abort motors are designed to jettison around 3 min. into the flight.
As well as providing the crew module and MLAS, ATK is responsible for the first stage, system integration and ground and mission operations, while Astrium provides the Vulcain 2-powered second stage. Lockheed Martin will provide subsystems and other support, including access to the same supply chain building components and systems for the NASA Orion capsule, as well as the use of its recently completed Space Operations Simulation Center near Denver. “With things like backshells, heatshields, guidance, navigation and control [GN&C] and so on, we are trying to leverage all those things,” says Rominger.
Lockheed Martin will work with ATK to tailor the design of subsystems for the crew compartment to suit the “specific mission requirements” of the LEO flights, says Scott Norris, Lockheed Martin lead for Liberty. Aside from “implied” cost savings from the use of a common supply chain, Norris says the entire development process will also be speeded up. “We have 21 months if selected to get to critical design review,” he notes. Lockheed Martin will provide crew interface systems design, sub-system selection, assembly, integration and mission operations support. ATK subsystems could include avionics, GN&C, propulsion, environmental control, docking and other components.
Astrium North America CEO John Schumacher says the initial second stage will be shipped to, where it will be integrated with the ATK-made first stage. However, “once the business case develops in the U.S., then we envision moving manufacture of the Liberty upper stage to the U.S.” Although the second stage is nearly identical to the standard Ariane 5 core, Schumacher says additional structural reinforcement is required. Despite this, he notes that no major tooling will be needed to accommodate the Liberty on the Ariane line, which can be grown from its current 6-7-per-year rate to “easily incorporate three to five more.”
As the-developed Vulcain 2 is used on the first stage of the Ariane 5, powering 47 consecutive launches, simulated altitude testing will be required to prove its air-starting capability for use in Liberty's second stage. Rominger says test sites at NASA's Stennis Space Center and Glenn Research Center are being evaluated. “We are working with both NASA centers to see which will be most appropriate.”
Analysis of the forces acting on the stack also indicates that, unlike NASA's similarly configured Ares 1 launcher, the Liberty will not be prone to potential thrust-oscillation issues at liftoff. The key difference is that the liquid oxygen tank is higher in the second stage than the liquid hydrogen tank, rather than the other way around in the Ares vehicle. The resulting change in weight distribution “changes the axial modes,” says Rominger. “We need no mitigation and are well within the requirements. NASA is fully on board with that,” he adds.
Other Liberty subcontractors now identified include wiring manufacturer/Labinal in Salisbury, Md., avionics and telemetry provider Cincinnati Electronics and Moog, which provides thrust-vector and propulsion control.