A. S. Shugarov

Astronomical aspects of cosmic threats: new problems and approaches to asteroid—comet hazard following the chelyabinsk event of February 15, 2013

A new definition of hazardous celestial bodies (HCBs) is introduced, in which the lower limit of the size of a HCB is reduced to 10 m. A new definition for threatening and collisional orbits of DCBs is introduced. The main astronomical factors that must be taken into account when creating systems for the detection of HCBs are analyzed. The most important of these are the uniformity of the distribution of points (regions) for the appearance of HCBs on the celestial sphere in near-Earth space and the practical limit for the velocity of approach of a HCB of 20 km/s (for 90% of bodies). It is shown that the creation of a system for the nearby detection of asteroids and comets arriving from the daytime sky requires the use of a space-based system. A concept for such a system, in which one or several optical telescopes are placed in the vicinity of the libration point L1 for the Sun—Earth system, is developed. Preliminary plans for such a system, called the System for the Detection of Daytime Asteroids (SDDA), are briefly described.

The World Space Observatory Ultraviolet (WSO–UV), as a bridge to future UV astronomy

Ultraviolet (UV) astronomy is a vital branch of space astronomy. Many dozens of short-term UV-experiments in space, as well as long-term observatories, have brought a very important knowledge on the physics and chemistry of the Universe during the last decades. Unfortunately, no large UV-observatories are planned to be launched by most of space agencies in the coming 10–15 years. Conversely, the large UVOIR observatories of the future will appear not earlier than in 2030s. This paper briefly describes the projects that have been proposed by various groups. We conclude that the World Space Observatory–Ultraviolet (WSO–UV) will be the only 2-m class UV telescope with capabilities similar to those of the HST for the next decade. The WSO–UV has been described in detail in previous publications, and this paper updates the main characteristics of its instruments and the current state of the whole project. It also addresses the major science topics that have been included in the core program of the WSO–UV, making this core program very relevant to the current state of the UV-astronomy. Finally, we also present here the ground segment architecture that will implement this program.

System of observation of day-time asteroids (SODA)

Abstract Chelyabinsk event of Feb 15, 2013 clearly demonstrated that decameter sizeNear EarthObjects (NEO) should be considered as hazardous ones. Another important lesson is that bodies approaching the Earth from day sky could not be discovered by any ground-based or near Earth space telescopes and the only way to detect these bodies reasonably well beforehand is to put the telescope(s) relatively far fromthe Earth.We proposed the project of space system SODA (System of Observation of Day-time Asteroids) for exhaustive detection of decameter (and larger) bodies approaching the Earth from the Sun direction (Chelyabinsk type meteoroids). The medium-size (30 cm) wide field telescopes are to be put into vicinity of L1 (Earth-Sun) point. Observations will be performed in barrier mode. Two options are considered: single spacecraft (SC) or pair of SCs. We describe major constituents and options of the project. The entire project could be implemented with off-shelf components and fits to low-cost project requirements. Special attention is paid to accuracy of orbit of the NEO. In a variant of two SCs capable to perform observation in triangulation mode accuracy of atmosphere entry point for Chelyabinsk-like body could be as high as few tens of kilometers.

The new field camera unit imaging instrument onboard WSO-UV

The WSO-UV project is an efficient multipurpose orbital observatory for high sensitivity imaging. The imaging instrument Field Camera Unit (FCU) onboard WSO-UV will be the first UV camera to be flown to a geosynchronous orbit. The observatory is planned to operate for at least five years and perhaps longer. WSO-UV will open new opportunities in planetary science, stellar astrophysics, extragalactic astronomy and cosmology. This paper provides an information on updated FCU instrument.

Space Instrumentation of the WSO-UV Mission for Astrophysics Research

The WSO-UV (World Space Observatory—Ultraviolet) space mission, optical design of the telescope, and main scientific instruments are briefly overviewed. A description of the photosensitive device of the WSO-UV mission based on a back-illuminated CCD with an antireflection coating is presented. Methods to improve the radiation resistance and reduce contamination on the CCD surface are described.

Space System for Detecting Hazardous Celestial Bodies Approaching Earth from the Daytime Sky (SODA)

The concept of the System for the Observation of Daytime Asteroids (SODA system) has been developed, the purpose of which is to detect at least 95% of hazardous celestial bodies larger than 10 m in size that fly towards Earth from the Sun side. Spacecraft, equipped with the optimum version, which has three wide-angle optical telescopes of small aperture (20–30 cm) will be placed in a halo orbit around the L1 libration point of the Sun–Earth system. This will provide a warning on the hazardous object, approaching from the Sun side, and will allow one to determine the orbit and the point of body entering Earth atmosphere to a sufficient accuracy, at least a few hours before the body collides with Earth. The requirements to the system are considered, the results of a preliminary design of the set of instruments have been described, the areas of visibility are calculated, and the versions of data transmission modes have been proposed. It has been shown that, in cooperation with other (particularly ground-based) projects aimed to observing objects flying from the night sky side, it is possible to detect in advance all hazardous bodies in the near-Earth space larger than 10 m in size that approach Earth from almost any direction.

Perspectives for Distributed Observations of Near-Earth Space Using a Russian–Cuban Observatory

The creation of a specialized network of large, wide-angle telescopes for distributed observations of near-Earth space using a Russian–Cuban Observatory is considered. An extremely important goal of routine monitoring of near-Earth and near-Sun space is warding off threats with both natural and technogenic origins. Natural threats are associated with asteroids or comets, and technogenic threats with man-made debris in near-Earth space. A modern network of ground-based optical instruments designed to ward off such threats must: (a) have a global and, if possible, uniform geographic distribution, (b) be suitable for wide-angle, high-accuracy precision survey observations, and (c) be created and operated within a single network-oriented framework. Experience at the Institute of Astronomy on the development of one-meter-class wide-angle telescopes and elements of a super-wide-angle telescope cluster is applied to determine preferences for the composition of each node of such a network. The efficiency of distributed observations in attaining maximally accurate predictions of the motions of potentially dangerous celestial bodies as they approach the Earth and in observations of space debris and man-made satellites is estimated. The first estimates of astroclimatic conditions at the proposed site of the future Russian–Cuban Observatory in the mountains of the Sierra del Rosario Biosphere Reserve are obtained. Special attention is given to the possible use of the network to carry out a wide range of astrophysical studies, including optical support for the localization of gravitational waves and other transient events.