MASS PROPERTIES MEASUREMENT INTHE X-38 PROJECT

摘要

This paper details the techniques used in measuring the mass properties for the X-38 family ofrntest vehicles. The X-38 Project was a NASA internal venture in which a series of test vehiclesrnwere built in order to develop a Crew Return Vehicle (CRV) for the International Space Station.rnThree atmospheric test vehicles and one spaceflight vehicle were built to develop therntechnologies required for a CRV.rnThe three atmospheric test vehicles have undergone flight-testing by a combined team from thernNASA Johnson Space Center and the NASA Dryden Flight Research Center. The flight-testingrnwas performed at Edward's Air Force Base in California. The X-38 test vehicles are based onrnthe X-24A, which flew in the ‘60s and ‘70s. Scaled Composites, Inc. of Mojave, California,rnbuilt the airframes and the vehicles were outfitted at the NASA Johnson Space Center inrnHouston, Texas.rnMass properties measurements on the atmospheric test vehicles included weight and balance byrnthe three-point suspension method, four-point suspension method, three load cells on jackstands,rnand on three in-ground platform scales. Inertia measurements were performed as well in whichrnIxx, Iyy, Izz, and Ixz were obtained. This paper describes each technique and the relative meritsrnof each.rnThe proposed measurement methods for an X-38 spaceflight test vehicle will also be discussed.rnThis vehicle had different measurement challenges, but integrated vehicle measurements werernnever conducted. The spaceflight test vehicle was also developed by NASA and was scheduledrnto fly on the Space Shuttle before the project was cancelled.