G. N. Kolesnichenko, A. V. Mironov, A. A. Vasjunin, S. V. Logunov

The aime of the work is to estimate the possibility of using multispectral photometric data for space object recognition. External design elements of various type space objects differ from each other and covered by different materials with different spectral reflection coefficients. These facts, as well as the fact that the ratio between the individual element sizes are different in different space objects, It leads to differences in spectral energy distribution of a reflected solar radiation. Information richness of any photometric data increases dramatically if there is an opportunity to compare the implementation of several spectral bands. We have analyzed the experimental data about color variations of space objects covered by different materials. We used average optical characteristics of various type space onfects presented in terms of color indices B-V and V-R by A. V. Didenko [3]. We were also analyzed some data for the DSP Spacecraft concerning with mirror flash (B-V=?0,05; V-R=+0,65) indicate that at this time the reflection comes from the silicon solar panesl that look like as a blue surface. If sunlight reflects from the surface of the spacecraft shell that the diffuse components appear; this time the spectral composition of solar radiation is almost unchanged and only the cover color is emphasized. Optical characteristics of some observed geostationary satellites according to [3] are given in Table and shown in Figs. 2 and 3. We calculated color indices B-V and V-R for several materials of spacecraft external surfaces which is also presented in Figs. 2 and 3. It is clearly seen in the figures that the color indices of the reflected solar radiation from various materials differ from each other greatly. Analysis of two-color diagrams (B-V, V-R) for geostationary objects showed that different types of objects are grouped by color index. In addition, Figure 3 shows color variations of the spacecraft DSP during a mirror flash formed by reflection of light from a solar panel (Fig. 1). Constructed plot shows strong differences in the color. During periods of time (t1-t3) and (t9-t11) it is shown the reflection from the diffuse component of the shell of the spacecraft, while from t3 to t8 the mirror components due to reflection of sunlight from the solar battery are clearly visible. These results suggest that multicolor photometry can take its rightful place among methods of space objects recognizing. Study of the spectral reflection coefficients of materials of external surfaces of space objects in the visible wavelength range can get their specific values, which corresponds to a particular coating material. Knowing the color characteristics of various construction elements, one can carry out the true relation of space object parts. Joint analysis of the observed reflex flares and the diffuse component of the phase functions of simple geometrical forms makes it possible to determine not only the spatial orientation of individual elements of the spacecraft, but also to describe the optical characteristics, condition of individual elements of the spacecraft, but also to describe the optical characteristics, condition and geometry of complex objects. The photometry in a larger number of differences spectral bands have to shoew the lager color differences and will us allow to carry out a partition of space objects into groups and solve the problem of recognition more reliable.