The motion model of Phobos and the technique of determination of parameters in the Phobos-Grunt project

The SC flight named Phobos-Grunt is planned to 2009 in Russia with purpose to deliver to the Earth samples of a ground of the Mars’s satellite Phobos. Within the framework of this project it is necessary to solve two tasks: to create a new theory of the Phobos motion and to develop a technique of joint specification of the SC and Phobos motion parameters both by independent measurements from the SC board, and by radio engineering measurements from a surface of the Earth. To approach with Phobos the SC has to execute complex dynamic operations — numerous transitions from one orbit into another. Thus КА will be in sphere of action of gravitational fields of the Sun, Mars and Phobos. Therefore an algorithm for joint specification of the SC initial conditions and Phobos ones are necessary for determination of motion parameters of the SC relative Phobos movement within the single dynamic model of theirs motions. For the beginning work of such algorithm it is necessary a priori knowledge of a Phobos orbit. This knowledge is given by the created theory of Phobos motion on set of measurements on an interval more than 100 years. The given work gives representation about the methodical approaches for the motion model and technique of determination of parameters.