NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Automated Method for Estimating Nutation Time Constant Model Parameters for Spacecraft Spinning on AxisCalculating an accurate nutation time constant (NTC), or nutation rate of growth, for a spinning upper stage is important for ensuring mission success. Spacecraft nutation, or wobble, is caused by energy dissipation anywhere in the system. Propellant slosh in the spacecraft fuel tanks is the primary source for this dissipation and, if it is in a state of resonance, the NTC can become short enough to violate mission constraints. The Spinning Slosh Test Rig (SSTR) is a forced-motion spin table where fluid dynamic effects in full-scale fuel tanks can be tested in order to obtain key parameters used to calculate the NTC. We accomplish this by independently varying nutation frequency versus the spin rate and measuring force and torque responses on the tank. This method was used to predict parameters for the Genesis, Contour, and Stereo missions, whose tanks were mounted outboard from the spin axis. These parameters are incorporated into a mathematical model that uses mechanical analogs, such as pendulums and rotors, to simulate the force and torque resonances associated with fluid slosh.
Document ID
20090022204
Acquisition Source
Kennedy Space Center
Document Type
Extended Abstract
Date Acquired
August 24, 2013
Publication Date
March 3, 2008
Publication Information
Publication: John F. Kennedy Space Center's Technology Development and Application 2006-2007 Report
Subject Category
Space Communications, Spacecraft Communications, Command And Tracking
Distribution Limits
Public
Copyright
Public Use Permitted.
No Preview Available