Pegasus(TM), a three-stage, air-launched, winged space booster was developed to provide fast and efficient commercial launch services for small satellites. The objective of this privately financed program between Orbital Sciences Corporation and Hercules Aerospace Company is to provide reliable space launch services at a low cost on near-term schedule. The aerodynamic design and analysis of Pegasus was conducted by NEAR without benefit of wind tunnel or flight tests using only computational aerodynamic and fluid dynamic methods.
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| The aerodynamic design and analysis was based on proven, state-of-the-art, readily available computational codes. Additional considerations in the aerodynamic design philosophy were code availability, ease of use, engineering capability, and confidence level. Since no wind-tunnel data on Pegasus were available for guidance, a high degree of confidence in the prediction methods was required to avoid a large amount of time spent validating the selected codes. The overall objective of the Pegasus aerodynamic analysis was to use the highest level code required for a specific task. |
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The aerodynamic analysis and support considered a number of different technical areas such as trajectory requirements, aerodynamic loading distributions, stability and control, and aerodynamic heating. The flight conditions included carriage and launch from the B-52 parent aircraft, transonic flight at high angles of attack, supersonic flight over the complete angle-of-attack range, and hypersonic flight to first-stage burnout. For this entire flight regime, it was necessary to select and validate appropriate prediction methods from the best technology available and estimate the level of accuracy achieved. The computational techniques ranged from engineering methods (empirical/database/theoretical codes) to computational fluid dynamics (CFD) methods. Economics, accuracy, and schedule were under constant consideration during the computational aerodynamic analyses.
The correlation of measured and predicted forces and moments from the first two flights of Pegasus served to demonstrate the feasability of the chosen computational approach for design and analysis purposes. NEAR is available to provide fluid mechanics consulting using the latest advanced technology.
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