GUIDANCE CONCEPTS FOR LUNAR LANDING
Interrupted-braking guidance system for soft lunar landings
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Interrupted-braking guidance system for soft lunar landings
Earth-based radio command of midcourse guidance for lunar flights is described, noting spacecraft, tracking station, and computing facility requirements
Iterative guidance mode applied to lunar landing for optimization of trajectories for minimum propellant consumption
Iterative guidance law for Saturn launch vehicle for lunar landing, examining trajectory optimization
Man-machine system in control and guidance of Saturn V launch vehicle, emphasizing participation during atmospheric phase of flight profile
Path adaptive guidance modes for Saturn space vehicle, particularly Iterative Guidance Mode
LM guidance and control systems performance verification
Deep space navigation and guidance technology, emphasizing simplification of onboard navigation procedures
Manual optimal guidance scheme using predictive display applied to launch vehicles during boost for continuous generation of predicted fuel- optimal trajectory
Guidance system requirements for unmanned Martian propulsive landing capsule
Manual steering problem and function of lunar module /LM/ manual hybrid guidance system, with automatic guidance system produced trajectory
As a NASA-sponsored GSRP Fellow, I worked with other researchers and analysts at Embry-Riddle Aeronautical University and NASA's ELV Division to investigate the effect of spacecraft fuel slosh. NASA's research into the effects of fuel slosh includes modeling the response in full-sized tanks using equipment such as the Spinning Slosh Test Rig (SSTR), located at Southwest Research Institute (SwRI). NASA and SwRI engineers analyze data taken from SSTR runs and hand-derive equations of motion to identify model parameters and characterize the sloshing motion. With guidance from my faculty advisor, Dr. Sathya Gangadharan, and NASA flight controls analysts James Sudermann and Charles Walker, I set out to automate this parameter identification process by building a simple physical experimental setup to model free surface slosh in a spherical tank with a simple pendulum analog. This setup was then modeled using Simulink and SimMechanics. The Simulink Parameter Estimation Tool was then used to identify the model parameters.
A stall recovery guidance system was designed to help pilots improve their stall recovery performance when the current aircraft state may be unrecognized under various complicating operational factors. Candidate guidance algorithms were connected to the split-cue pitch and roll flight directors that are standard on large transport commercial aircraft. A new thrust guidance algorithm and cue was also developed to help pilots prevent the combination of excessive thrust and nose-up stabilizer trim. The overall system was designed to reinforce the current FAA recommended stall recovery procedure. A general transport aircraft model, similar to a Boeing 757, with an extended aerodynamic database for improved stall dynamics simulation fidelity was integrated into the Vertical Motion Simulator at NASA Ames Research Center. A detailed study of the guidance system was then conducted across four stall scenarios with 30 commercial and 10 research test pilots, and the results are reported.
Analysis of guidance system errors resulting from initial misalignments of both the accelerometer and stabilizing gyros, the drift of the stabilized element during flight and errors in measuring the vehicle motions
This paper describes a detailed mathematical model which has been assembled to study automatic approach and landing guidance concepts to bring a VTOL aircraft onto a small aviation ship. The model is used to formulate system simulations which in turn are used to evaluate different guidance concepts. Ship motion (Sea State 5), wind-over-deck turbulence, MLS-based navigation, implicit model following flight control, lift fan V/STOL aircraft, ship and aircraft instrumentation errors, various steering laws, and appropriate environmental and human factor constraints are included in the model. Results are given to demonstrate use of the model and simulation to evaluate performance of the flight system and to choose appropriate guidance techniques for further cockpit simulator study.
The tumbling motion of vehicles entering planetary atmospheres is analyzed. A differential equation governing the tumbling motion, its arrest, and the subsequent oscillatory motion is obtained and identified as the equation for the fifth Painleve transcendant. An approximate analytical solution for the transcendant is derived. Comparisons with results obtained from numerical integration of the exact equations of motion indicate that the solution for the angle-of-attack history is sufficiently accurate to be of practical use.
Closed-form solutions for the motion of a rocket-powered vehicle during atmospheric ascent and closed-form solutions for unpowered atmospheric reentry are developed. These closed-form solutions are then used to develop a simplified guidance scheme and to develop a variation-of-parameters integration of more accurate equations of motion with the closed-form solutions as base solutions. The variation-of-parameters integration of the more accurate equations of motion also allows the transition partial derivative matrices associated with these equations to be easily developed. Then the partial derivative transition matrices are used to develop a guidance scheme based on the more accurate equations of motion instead of the less accurate closed-form solutions.
Differential equations of motion linearized about nominal calculus of variation solution to determine coefficients of guidance function