Documents / Official release
This Defense Intelligence Reference Document, DIA-08-0912-008, is dated 12 January 2010. It was prepared by the Defense Warning Office's Acquisition Support Division at the Defense Intelligence Agency as one of a series of FY 2009 technology reports under the Advanced Aerospace Weapon System Applications program. It reviews materials for launch vehicles, space vehicles and reusable rocket engines, including aluminum alloys, polymer and metal matrix composites, titanium and nickel alloys, and titanium aluminides. It concludes that newer materials and integrated design could improve on the space shuttle.
From the source: Release of 2026-09-18 Incident: 1/12/10, Las Vegas, Nevada. Released with redactions. This document is a Defense Intelligence Reference Document (DIRD), a technical reference format used by the Defense Intelligence Agency (DIA) to capture baseline knowledge on a specific topic for later analytic use. DIRDs are best understood as reference and synthesis products rather than as original research. It is one of 38 DIRDs produced under the Advanced Aerospace Weapon System Applications Program (AAWSAP) between 2009 and 2011. Because AAWSAP’s scope permitted a broad range of supporting topics, not every DIRD in the series directly concerns aerospace systems or future threat assessment. The following summary reflects the DIRD’s scope and framing at the time of writing and should not be read as implying current validation of the concepts discussed. This DIRD surveys the structural materials needed for advanced aerospace platforms and argues that material choice cannot be separated from overall vehicle design, because launch vehicles, space vehicles, reusable systems, and propulsion hardware each face different temperature, durability, weight, and manufacturing constraints. The report reviews a range of candidate material classes, including advanced aluminum alloys; polymer-, aluminum-, and titanium-matrix composites; titanium alloys; nickel-base alloys; refractory metals; ceramic-matrix composites; carbon-carbon composites; and titanium aluminides. It emphasizes that balancing performance against practical limits such as fabrication methods, cost, inspection, contamination control, and service environment remains a major challenge. Its overall conclusion is that many promising materials exist, but their usefulness depends on application-specific tradeoffs and on closer integration of material selection with design and manufacturing, with some systems judged to be more valuable targets for development than others.
UNCLASSIFIED//POlt OPPl@IAL YSI!! 8HLY construction to be considered too risky. Today, the combination of higher toughness alloys and FSW opens up the possibility of greater design flexibility resulting in lighter large structures with equal or greater reliability than earlier ones. In sum, metallic, nonreusable (at least nominally so) launch vehicles made from advanced Al alloys and fabricated through FSW constitute an incremental but significant improvement over earlier versions . In recent years, PM Cs have matured significantly. For many components that are not exposed to elevat ed temperatures, PMCs provide a degree of design flexibility not read ily available in meta ls. Consequently, PMC materials have begun to supplant Al alloys in the construction of commercial subson ic aircraft. The use of PMCs in the empennage of the Boeing 777 was one of the first examp les of Al alloys being displaced. Subsequently, the new Boeing 787 has more structure made from composites than from metallic materials. Once PMCs are introduced into a structure in sign ificant quantit ies, a constraint related t o galvanic incompatibility between the PMC st ructure and any adjoining Al all oys also is introduced. When a PMC structure is in direct contact with an Al alloy structure, catastrophic corrosion of the Al alloy components can occur. In the Boeing 787, the remedy for this concern is the use of titan ium (Ti) all oys in areas where there is direct contact between t he metallic and the PMC structures. This is directly analogous to the plastic bushing a plumber puts in the j oint between copper and iron piping. Notwithstanding this constra int, the specific strength and stiffness of PMC structures make a compell ing argument for their appl ication in high-performance structures, such as launch veh icles . Composite structures can be manufactured using one of th ree methods: hand layup of pre-preg, automated tow placement, and resin transfer molding. • The most rudimentary of these, but also the most flexible, is hand layup of pre -preg. This method uses sheets of material that contain both the fiber and the polymeric matrix (called pre-preg). The polymeric matrix can be either a thermoset (for example, epoxy) or a thermoplastic. Individual plies are cut from the pre-preg typica lly using a numerically controlled laser or mechanical cutting device and are la id up to form the desired shape. Areas that have heavier loads contain more plies locally, and the plies are cut in an orientation with respect to the fiber direction in the pre-preg to ach ieve the desired strength relative to the principa l load path. These plies are carefully placed according to a drawing (blueprint), making hand layup a labor-intensive process and, therefore, making parts made using th is method expensive . During ply placement, it is crit ical that no ply wrinkles are introduced, as these create severe reductions in the local load-bearing capability of the fina l component. Once all the plies are in their proper places, the article is placed in a vacuum-tight bag that is evacuated and placed in an autoclave for curing of the epoxy matrix or fusing of the thermoplastic. A disadvantage of a pre-preg whose matrix is a thermoset is limited shelf life. In practice, this is managed to a degree by storing the pre-preg in a freezer to slow the rate of chemica l reaction t hat sets the epoxy. However, th is does not completely halt the reaction, causing these materials to have a shelf life beyond wh ich they are not easily manipulated during layup and do not develop full strength after curing in the autoclave. An additional issue is out t ime-the time the pre-preg can be out of the freezer during layup before the reaction proceeds at an accelerated rate and reaches a point at which the 3 UNCLASSIFIED//F8R 8FFUiil>I. 11&5 ON! X
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Official release, from the pursue collection. The PDF is mirrored here; the original link is above. 27 pages are in the text index: search them above, or from the library's search.