Analysis of the Sky Scanning Efficiency in the Lyra-B Space Experiment

Abstract

The Lyra-B space experiment (SE) is a high-precision multicolor multiple all-sky photometric survey of stars and star-like objects. The experiment will be conducted from the Russian segment of the International Space Station (ISS). For this purpose, a 0.5-m telescope will be installed onboard (or, more precisely, outboard) the ISS, which will observe stars in a scanning mode. The Lyra-B SE was included in the program of scientific experiments at the ISS fairly long ago. At the beginning of the SE design it was thought that the ISS would exist “eternally” and the time needed for the full-fledged implementation of the experiment would be allocated. Today, however, the situation has changed. In 2025 the ISS will possibly cease to exist either as the space station as a whole or in the form in which it exists now. Hence there arises the problem to perform the entire volume of observations in a maximally short time, i.e., to find an optimal sky scanning strategy that would ensure a maximum duration of observations. In addition, we consider two related questions: with what density will the observations be distributed over the sky and how many times will a point in the sky fallen within the field of view of the Lyra-B telescope be observed in successive orbital revolutions? This question is important for investigating variable stars, determining the orbits and axial rotation periods of asteroids, and ensuring a specified photometric accuracy over the entire sky.