@article{<br>	11311_554138,<br>	author = {Owis, A. H. and Topputo, Francesco and BERNELLI ZAZZERA, Franco},<br>	title = {Radially Accelerated Optimal Feedback Orbits in Central Gravity Field with Linear Drag},<br>	year = {2009},<br>	journal = {CELESTIAL MECHANICS & DYNAMICAL ASTRONOMY},<br>	volume = {103},<br>	abstract = {The solution of a feedback optimal control problem arising in orbital mechanics<br>is addressed in this paper. The dynamics is that of a massless body moving in a central gravitational force field subject also to a drag and a radial modulated force. The drag is linearly proportional to the velocity and inversely proportional to the square of the distance from the center of attraction. The problem is tackled by exploiting the properties of a suitably devised linearizing map that transforms the nonlinear dynamics into an inhomogeneous linear system of differential equations supplemented by a quadratic objective function. The generating functionmethod is then applied to this newsystem, and the solution is back transformed in the old variables. The proposed technique, in contrast to the classical optimal control problem,<br>allows us to derive analytic closed-loop solutions without solving any two-point boundary value problem. Applications are discussed.},<br>	keywords = {Orbital transfers; Feedback optimal control; Generating function; Linear drag},<br>	url = {http://dx.doi.org/10.1007/s10569-008-9161-6},<br>	doi = {10.1007/s10569-008-9161-6},<br>	pages = {1--16},<br>	number = {1}<br>}<br>