High-Performance Composites

MAR 2013

High-Performance Composites is read by qualified composites industry professionals in the fields of continuous carbon fiber and other high-performance composites as well as the associated end-markets of aerospace, military, and automotive.

Issue link: https://hpc.epubxp.com/i/110847

Contents of this Issue


Page 63 of 67

focus on design Space miSSion maximized CFRP design and manufacturing flexibility prove key in first spacecraft I n 2008, the U.S. Navy spent tens of millions of dollars to shoot down a 5,000-lb/2,268-kg NROL-21 satellite that had lost power and would soon plummet to earth with hazardous fuel inside. Although the National Aeronautics and Space Admin. (NASA, Washington, D.C.) had already forged international agreements and policies with its partners to reduce the threat of falling space debris, this event brought the issue into sharp relief for space agencies globally and the public at large. "It became necessary to develop some method for disposing of the spacecraft," says Robert H. Estes, a lead engineer at NASA's Goddard Space Flight Center (Greenbelt, Md.). "We decided the best way to do this is to ablate the spacecraft upon reentry, resulting in a very small amount of debris left that could harm people or the environment." Thus, when Goddard began work on the Global Precipitation Measurement (GPM) Core satellite (see "Learn More," p. 64), a key design requirement was demiseability — minimizing the structure's ability to survive reentry. Demiseability offers more than ground safety. Normally, a spacecraft must be brought down while it can still be controlled during reentry, but a fully demiseable spacecraft needs no propellant for reentry, so the propulsion system can be simplified or eliminated, and the craft can stay in orbit until its propellant is expended. This increases overall satellite cost-efficiency by extending mission length, reducing the COBHAM DEMISEABLE FUEL TANK FOR GLOBAL PRECIPITATION MEASUREMENT (GPM) CORE SATELLITE 55.5 inches/ 1,410 mm 48 plies 46.3 inches/ 1,175 mm 24 plies ALUMINUM LINER SKIRT OVERWRAP Propellant Management Device TANK/SKIRT ASSEMBLY 6061-T62 aluminum liner (0.05 inch/1.27 mm thick) 4 inches/ 101.6 mm 46.5 inches/1,180 mm T-1000 carbon fiber/ epoxy overwrap liner (average 0.111inch/0.281-cm thick laminate) Skirt bonded to tank Cusps on outer ring of skirt feature bonded-in fasteners for attachment to spacecraft Design Results • Composite overwrap enables use of an aluminum liner thin enough to disintegrate upon reentry, light enough to meet weight restrictions and strong/stiff enough to survive launch. 62 | high-performanCe ComposiTes • To accommodate a late-program modifica- • The carbon fiber overwrap helped tion, composites tailorability permitted Cobham to beat the program schedule, rework of the winding design rather than hit cost targets and lengthen spacecraft the expensive tooling remake necessary mission life, reducing the frequency of for all-aluminum or titanium construction. satellite replacement.

Articles in this issue

Archives of this issue

view archives of High-Performance Composites - MAR 2013