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Atmospheric Ascent Guidance for Rocket-Powered Launch VehiclesAn advanced ascent guidance algorithm for rocket- powered launch vehicles is developed. This algorithm cyclically solves the calculus-of-variations two-point boundary-value problem starting at vertical rise completion through main engine cutoff. This is different from traditional ascent guidance algorithms which operate in a simple open-loop mode until high dynamic pressure (including the critical max-Q) portion of the trajectory is over, at which time guidance operates under the assumption of negligible aerodynamic acceleration (i.e., vacuum dynamics). The initial costate guess is corrected based on errors in the terminal state constraints and the transversality conditions. Judicious approximations are made to reduce the order and complexity of the state/costate system. Results comparing guided launch vehicle trajectories with POST open-loop trajectories are given verifying the basic formulation of the algorithm. Multiple shooting is shown to be a very effective numerical technique for this application. In particular, just one intermediate shooting point, in addition to the initial shooting point, is sufficient to significantly reduce sensitivity to the guessed initial costates. Simulation results from a high-fidelity trajectory simulation are given for the case of launch to sub-orbital cutoff conditions as well as launch to orbit conditions. An abort to downrange landing site formulation of the algorithm is presented.
Document ID
20030000844
Document Type
Conference Paper
External Source(s)
Authors
Dukeman, Greg A. (NASA Marshall Space Flight Center Huntsville, AL United States)
Date Acquired
August 21, 2013
Publication Date
January 1, 2002
Subject Category
Launch Vehicles and Launch Operations
Report/Patent Number
AIAA Paper 2002-4559
Meeting Information
AIAA Guidance, Navigation and Control Conference(Monterey, CA)
Distribution Limits
Public
Copyright
Public Use Permitted.

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