descent trajectory
1.When lunar probes descend from 100km height to 15km height, the Keplerian trajectory has around 15km high pericynthion. Simulation result shows that there is a point near the pericynthion, and if the continued-propulsion descent trajectory begins at this point other than the pericynthion more fuel will be saved.
2.Using the indices of trajectory follow error and steering busyness in evaluation of the steering stability, a quadratic form performance index function for the neuron learning was established and the tuning of the connection weight values of the single neuron controller was realized using the algorithm of gradient descent.
