Ya.S. Yatskiv

CORONAS-F observations of active phenomena on the sun

Abstract Complex observations in the framework of the CORONAS-F Mission aimed at the study of active phenomena inthe solar corona are described. The main features are given for the following experiments: (1) XUV-imaging spectroscopy with high temporal and spatial resolution, (2) X-ray spectroscopy, (3) X-ray and gamma-ray photometer/spectrometer, and (4) solar cosmic rays. Some new observational data on the structure and dynamics of flares and transient events are discussed along with their analysis.

Objectives of a prospective Ukrainian orbiter mission to the moon

Abstract Ukraine has launch vehicles that are able to deliver about 300 kg to lunar orbit. A future Ukrainian lunar program may propose a polar orbiter. This orbiter should fill principal information gaps in our knowledge about the Moon after the Clementine and Lunar Prospector missions and future missions like Smart-1, Lunar-A, and Selene. We consider that this can be provided by radar studies of the Moon with supporting optical photopolarimetric observations from lunar polar orbit. These experiments allow one to better understand global structure of the lunar surface at a wide range of scales, from microns to kilometers. We propose three instruments for the prospective lunar orbiter. They are a synthetic aperture imaging radar, ground-penetrating radar, and imaging UV-spectropolarimeter. The main purpose of the synthetic aperture imaging radar experiment is to study with high-resolution (50 m) permanently shadowed sites in the lunar polar regions. These sites are cold traps for volatiles, and have a potential for resource utilization. Possible presence of water ice in the regolith in the sites makes them interesting for long-term manned bases on the Moon. Radar and optical imaging and mapping of other interesting regions could be also planned. Multi-frequency, multi-polarization sounding of the lunar surface with ground-penetrating radar can provide data about internal structure of the lunar surface from meters to several hundred meters deep. The ground-penetrating radar can be used for measuring megaregolith properties, detection of cryptomaria, and studies of internal structure of the largest craters. Modest spatial resolution (50 m) of the imaging UV-spectropolarimeter should provide total coverage (or coverage of a large portion) of the lunar surface in oblique viewing at large phase angles. Polarization degree at large (>90°) phase angles bears information about characteristic size of the regolith particles. Additional experiments could use the synthetic aperture imaging radar system, e.g., bistatic radar sounding with the on-board transmitter and Earth-based receiver, and interferometry with the on-board transmitter and two Earth-based receiving antennas that allows reconstruction of the surface topography with high resolution.

Remote Sensing of Aerosol in the Terrestrial Atmosphere from Space: New Missions

The distribution and properties of atmospheric aerosols on a global scale are not well known in terms of determination of their effects on climate. This mostly is due to extreme variability of aerosol concentrations, properties, sources, and types. Aerosol climate impact is comparable to the effect of greenhouse gases, but its influence is more difficult to measure, especially with respect to aerosol microphysical properties and the evaluation of anthropogenic aerosol effect. There are many satellite missions studying aerosol distribution in the terrestrial atmosphere, such as MISR/Terra, OMI/Aura, AVHHR, MODIS/Terra and Aqua, CALIOP/CALIPSO. To improve the quality of data and climate models, and to reduce aerosol climate forcing uncertainties, several new missions are planned. The gap in orbital instruments for studying aerosol microphysics has arisen after the Glory mission failed during launch in 2011. In this review paper, we describe several planned aerosol space missions, including the Ukrainian project Aerosol-UA that obtains data using a multi-channel scanning polarimeter and wide-angle polarimetric camera. The project is designed for remote sensing of the aerosol microphysics and cloud properties on a global scale.

Astronomy in the Elbrus Region

Astronomical research in the Elbrus Region are conducted in the wide international cooperation. They are implemented in under the aegis of the International Association of Academies of Sciences in collaboration with the Euro-Asiatic Association of Universities. Authors outline the important scientific results obtained in the fields of fundamental, applied, and search studies within the international astronomical programs at the Terskol Peak Observatory. They refer to the problem of the identification of diffuse interstellar bands, studies of the star light-curve, detection of optical residuals of gamma-ray bursts, determination of the kinematic and physical characteristics of minor bodies of the Solar System (asteroids and comets), as well as investigation of space objects of technogenic origin in the near-Earth space environment.

Meteoroid Hazard in the Leo Space Environment

Two different approaches to the problem of meteoroid hazard in the LEO space environment are considered. The traditional approach is based on use of the Integrated Influx Density (IID) of space particles and bodies derived for the wide range of masses (10 −12 ≤ M ≤ 1022 g) for calculation of the probability of collision between spacecraft and these bodies. Another approach relies upon an indirect method for detection of numerous parent bodies by means of observations of meteor showers. Using the Kharkiv Meteor Data Base (KMDB), the probabilities of collision between parent bodies and the Earth were calculated.