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Unformatted text preview: 1 ASE 324L Design Project #1: Material Selection for a Spacecraft Antenna Background: As a spacecraft structural designer, you are to specify the material and shape of a boom structure to support a communication antenna from a small satellite. Consider the following points: • The quality and coverage of the communications signal depend on the antenna boom’s ability to maintain its pointing accuracy despite environmental disturbances (attitude changes, propulsion system firings, micrometeoroid impingement, etc.). In particular, the boom must minimize the deflection under thermal loads, and accommodate a thermal gradient across the depth of the boom due to the solar flux of 1000 BTU/hr with a minimum tip deflection. • In addition, the communication signal is particularly susceptible to low frequency vibrations, so the natural frequency in the bending mode should be maximized. A high internal damping, or loss factor ( > 0.0005), is desired so that the boom will quickly return to its equilibrium state if it is disturbed. • Since the spacecraft has a strict weight budget, a minimum mass is desired for the structure. • The antenna boom must survive particularly severe shock and vibration loads during launch, so the material chosen must have reasonably good tensile strength ( > 30 ksi) and fracture toughness ( > 10 ksi-in1/2). • Magnetic materials, such as steels and nickel alloys would interfere with the antenna pattern and are not allowed for the design. • Low cost (< $500/lbm) is also desirable, but not required....
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This note was uploaded on 09/18/2011 for the course ASE 324L taught by Professor Leichti during the Spring '08 term at University of Texas.
- Spring '08