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Preliminary OARE absolute acceleration measurements on STS-50On-orbit Orbital Acceleration Research Experiment (OARE) data on STS-50 was examined in detail during a 2-day time period. Absolute acceleration levels were derived at the OARE location, the orbiter center-of-gravity, and at the STS-50 spacelab Crystal Growth Facility. The tri-axial OARE raw acceleration measurements (i.e., telemetered data) during the interval were filtered using a sliding trimmed mean filter in order to remove large acceleration spikes (e.g., thrusters) and reduce the noise. Twelve OARE measured biases in each acceleration channel during the 2-day interval were analyzed and applied to the filtered data. Similarly, the in situ measured x-axis scale factors in the sensor's most sensitive range were also analyzed and applied to the data. Due to equipment problem(s) on this flight, both y- and z- axis sensitive range scale factors were determined in a separate process (using the OARE maneuver data) and subsequently applied to the data. All known significant low-frequency corrections at the OARE location (i.e., both vertical and horizontal gravity-gradient, and rotational effects) were removed from the filtered data in order to produce the acceleration components at the orbiter's center-of-gravity, which are the aerodynamic signals along each body axes. Results indicate that there is a force of unknown origin being applied to the Orbiter in addition to the aerodynamic forces. The OARE instrument and all known gravitational and electromagnetic forces were reexamined, but none produce the observed effect. Thus, it is tentatively concluded that the Orbiter is creating the environment observed.
Document ID
19930013398
Acquisition Source
Legacy CDMS
Document Type
Technical Memorandum (TM)
Authors
Blanchard, Robert C.
(NASA Langley Research Center Hampton, VA, United States)
Nicholson, John Y.
(Vigyan Research Associates, Inc. Hampton, VA., United States)
Ritter, James
(Lockheed Engineering and Sciences Co. Hampton, VA., United States)
Date Acquired
September 6, 2013
Publication Date
February 1, 1993
Subject Category
Spacecraft Design, Testing And Performance
Report/Patent Number
NASA-TM-107724
NAS 1.15:107724
Accession Number
93N22587
Funding Number(s)
PROJECT: RTOP 506-48-11-05
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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