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/ /FOR OFFl@IAL l!ISI!!! 9HLY Table 1 shows there are essentially 10 distinct classes of candidate materials for use in a reusable 550 vehicle. Their usefulness for specific applications and components depends on the operating temperature regime and the design -limiting material property . Some background and characteristics of each of these materials are described in this section. Applications of some of these materials have already been addressed, so the discussion here is limited to applications for a reusable S5O veh icle. Advanced Al Alloys Th is class of materials is limited by its temperature capability because, even if used in an embedded structure, the thermal soakback from the hot external structure can lead to softening in real time or averaging during extended exposure (that is, after several missions). Scientists have worked to develop high-temperature powder-metallurgy Al alloys, mainly alloys containing Fe, cobalt (Co) and cesium (Ce) or Mn and Si. These alloys are not routinely produced today owing to a lack of demand stemming in part from their cost and their relative lack of maturity as judged by the high variability in mechanical properties between lots of material. Consequently, the main application for Al alloys is in the crew compartment itself, where temperatures must be maintained at levels that are tolerable for the human occupants. Al alloys have marginal stiffness, even on a density-corrected basis. However, using fabricated panels with Al face sheets and a lightweight core can minimize this lim itation. Such panels have a high section modulus, which increases the structural stiffness without adding much weight. Earlier uses of phenolic honeycomb cores experienced only limited success because of the tendency of the core to absorb water from the environment if a breach of the face sheet or the face sheet core bond occurred . Today, Al pheno lic honeycomb sandwich construction is unpopular among aircraft and spacecraft designers because of this earlier, unfavorable experience. However, a new possibility for lightweight stiff structures-Al face sheets with a foamed Al alloy core-is worthy of consideration. Considerable progress in making uniform-density Al and other metallic foams has been realized in the past 10 years . This new class of sandwich materials is sufficiently different from the earlier versions to merit a carefu l evaluation. Polymer Matrix Composites As described in the Launch Vehicle section, polymer matrix composites have excellent strength, stiffness, fatigue resistance, and fracture toughness. All polymeric materials are to some degree susceptible to degradation when exposed to ultraviolet (UV) radiation. For an orbiting vehicle, a major limitation is the effects of UV radiation on the polymer matrix. Given their limited time at altitude, this vulnerability is not an issue for launch vehicles; however, it is a concern for structures that remain in orbit for an extended time at altitudes where the UV intensity is much greater. Although there are coatings that protect substrates (PMCs in this case) from UV radiation, the risk of these coatings being breached and the uncertainty about their effectiveness in orbit make UV exposure an ongoing concern. Any consideration of using PMCs for exterior applications would need to include an evaluation of their effectiveness. As discussed for Al alloys, PMCs also could be considered for interior applications where temperatures are within the material capabilities. As discussed earlier, some polyimide resins are usable up to about 300 °Celsius; therefore, the low density and excellent specific stiffness of PMCs make them viable candidates for some components. As also discussed, some polyimides, such as PMR-15, contain methylenedianiline, and care must be taken to 11 UNCLASSIFIED/ /FOR OFFIQl.\k Uili QPlk¥
Not linked to a story yet.
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.