Applications of composite

materials in missile and space hardware

SHARATH.B.NM.Tech. 2nd semester

BMSCE

Missiles – a brief history

Rocket used by Tipu Sultan’s army.

• References to missiles dates back to the Vedic age in India.

• Fiber glass was used for filament winding of rocket motor cases in 1950s.

• Now Kv-Ep filament is used.

Trident I missile• Gr-Ep cloth readily conforms to the irregular shapes and reduces manufacturing

time by up to 50%.

• This results in 20% weight savings over Aluminum.

Image for representation(Integrated Publishing - Your source for military specifications and educational publications)

• Today as much as 60% of the weight of this missile is of the composites.

• Sitka spruce laminated with Gl-Ep cloth is used in nose fairing.

• Polyphenylene sulphide matrix reinforced with 40% glass fiber is used in electronic packaging.

Trident 1 (Lockheed Martin)

Tomahawk missile• Tail fins and elevons are made of molded and compression Gr-Ep respectively.

• Wings are made of adhesively bonded thermoplastics.

• Previously the tail fins, elevons and wings were made of Aluminum.

• The shaft used in turbo shaft engine uses Titanium metal matrix composites.

Space hardware

• They are weight critical structures.

• Dominant parameters are high stiffness and low thermal distortion rather than strength.

• Other critical factors are thermal and electrical conductivity, stability under vacuum and space radiation.

International Space Station (Wikipedia)

Satellites and communication systems

ATS support truss (Hercules, Inc.)

• The reflector support truss of Application Technology Satellite(ATS) used high modulus Gr-Ep tape.

• This is a high stiffness, low thermal expansion material.

• This resulted in weight saving of 50% over an equivalent Aluminum truss.

Truss supporting the antenna dish (Hercules, Inc.)

Tracking and Data Relay Satellite System (TDRSS)

TDRSS antenna partially assembled (Hercules, Inc.)

• Composites are applied in antenna dish support ribs.

• The tube consists of lay-up of Gr-Ep, which weigh 181g.

TDRSS (Hercules, Inc.)

Large Space Telescope (LST)

LST (Mayer, N.J.: Composite Materials in Space Structures)

• The LST uses Gr-Ep truss, which supports the primary and secondary mirrors.

• It is not possible to use conventional metals owing to their expansion or contraction.

• Gr-Ep has axial expansion of less than 2 microns.

Space shuttle

Credit: NASA

• The space shuttle uses composites in many areas resulting in reduction of weight by 1633 kg.

• It uses Gr-Ep skins for the maneuvering system and Titanium tubes reinforced with B-Ep in the aft structure.

• The pressure vessels are made of Titanium wrapped with Kv-Ep.

• The space shuttle has 242 uni-directional B-Al tubes which serve as main frame and nose landing gear struts.

• Its lower thermal conductivity helps in lower heat flow in to the payload bays, reducing thermal insulation requirements.

Courtesy: Mater. Eng., Jan 1980, p. 66

Space shuttle cargo-bay doors (Aviation Week Technology, 1982)

• The cargo bay doors use Gr-Ep composite.

• They are each 18.3m long.

• Gr-Ep was chosen due to its low coefficient of thermal expansion, which prevents warping due to asymmetrical heating.

END