Analysis of the features of the implementation of the launch unit flight scheme for micro spacecraft injections in an intermediate orbit with synchronous precession

The article considers features of the implementation of the launching scheme for a group of small spacecraft at the stage of the Volga type launch unit operation during the transition from the reference orbit formed by the “Soyuz 2.1 v” launch vehicle to the intermediate orbit, where the small spacecraft separate. The orbit with synchronous precession velocity of the ascending node longitude with respect to the working orbit is chosen as an intermediate orbit, to which the small spacecraft transfer independently, using their propulsion system, after separation from the launch unit. The article solves the problem of choosing the rational orientation of the launch unit during the release of pulses, in the passive flight segments, as well as for the safe separation of the small spacecraft in an intermediate orbit with synchronous precession. Parameters of maneuvers to flood launch unit after separation of small spacecraft are calculated. Numerical results of fuel consumption for direct deorbiting and selection of maneuvering intervals for launch unit submersion in a given area of the world ocean are obtained. The calculations of the Earth shadow- and semishadow-sunlight time for small spacecraft are performed.

Determination of an Intermediate Perturbed Orbit using Multiple Observations

Two methods are briefly stated for finding the preliminary orbit of a small celestial body from its three or more pairs of angular measurements and the corresponding time instants. The methods are based on using the approach that we previously developed for constructing the intermediate orbit from a minimum number of observations. This intermediate orbit allows for most of the perturbations in the motion of the body under study. The methods proposed use the Herget's algorithmic scheme that makes it possible to involve additional observations as well. Using the determination of orbits of some asteroids as examples, we compare the results obtained by applying the Herget multiple-observation algorithm and the proposed methods. The comparison shows that the proposed methods are an efficient means for studying perturbed motion. They are especially advantageous if applied to high-precision observational data covering short orbital arcs.

Numerical efficiency of the elliptic function expansions of the first-order intermediary for general planetary theory

We compare numerical efficiency of the two kinds of series for the first-order intermediate orbit for general planetary theory: (1) the classical expansion involving mean longitudes of the planets; (2) an expansion resulting from the theory of elliptic functions. We conclude that mutual perturbations of close couples of planets (the ratio of major semi-axes ∼ 1) can be represented in more compact form with the aid of the second kind of series.