Torsional balloon flight line oscillations: Comparison of modelling to flight data

Journal Article · 10 May 2017 · Advances in Space Research

DOI: https://doi.org/10.1016/j.asr.2017.05.003 · OSTI ID:1462045

Aubin, Francois ^[1]; Bayman, Benjamin ^[1]; Hanany, Shaul ^[1]; Franco, Hugo ^[2]; Marsh, Justin ^[2]; Didier, Joy ^[3]; Miller, Amber D. ^[3]

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1. Univ. of Minnesota, Minneapolis, MN (United States). School of Physics and Astronomy
2. Columbia Scientific Balloon Facility, Palestine, TX (United States)
3. Columbia Univ., New York, NY (United States). Physics Dept.

During the EBEX2013 long duration flight the payload was free to rotate in azimuth. The observed azimuth motion consisted of a superposition of full rotations with a period of 10—30 min and oscillatory motion with an amplitude of tens of degrees, average period of 79 s, and period dispersion of 12 s. We interpret the full rotations as induced by slow rotations of the balloon and the shorter period oscillatory motion as due to torsional oscillations of the flight line. We derive the torsional stiffness of the flight line using the bifilar pendulum model and apply it to the flight line of the EBEX2013 payload. We find a torsional spring constant of 36 kg m²/s² corresponding to a period of 58 s. Here, we conclude that the bifilar model, which accounts for the geometry of the flight line but neglects all material properties, predicts a stiffness and period that are 45% larger and 25% shorter than those observed. It is useful to have a simple, easy to use, coarse approximation for the torsional constant of the flight line.

• Research Organization: Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States). National Energy Research Scientific Computing Center (NERSC)
• Sponsoring Organization: USDOE Office of Science (SC), Advanced Scientific Computing Research (ASCR)
• OSTI ID: 1462045
• Journal Information: Advances in Space Research, Vol. 60, Issue 3; ISSN 0273-1177
• Publisher: ElsevierCopyright Statement
• Country of Publication: United States
• Language: English