Long gamma-ray bursts (GRB), explosions of very massive stars, provide crucial information on stellar and galaxy evolution, even at redshifts z ~ 8 - 9.5, when the Universe was only 500-600 million years old. Recently, during observations of a galaxy at a redshift of z ~ 11 (400 million years after the Big Bang), a bright signal, named GN-z11-flash, shorter than 245 s was detected and interpreted as an ultraviolet flash associated with a GRB in this galaxy, or a shock-breakout in a Population III supernova. Its resulting luminosity would be consistent with that of other GRBs, but a discussion based on probability arguments started on whether this is instead a signal from a man-made satellite or a Solar System object. Here we show a conclusive association of GN-z11-flash with Breeze-M upper stage of a Russian Proton rocket on a highly elliptical orbit. This rules out GN-z11-flash as the most distant GRB ever detected. It also implies that monitoring of a larger sample of very high redshift galaxies is needed to detect such distant GRBs. This also highlights the importance of a complete database of Earth satellites and debris, which can allow proper interpretation of astronomical observations.

A project of building a cluster of optical telescopes dedicated to satellite and space debris tracking has been recently started in the Astronomical Observatory of Adam Mickiewicz University in Poznan. The instrument will be composed of 5 independent OTAs (optical tube assembly) ranging from 0.2 to 0.7m and will allow to collect hundred thousands of astrometric positions of Earth-orbiting targets per night. Fully robotic operation of the new telescope will include automatic decision making, based on changing weather conditions and observing alerts received, as well as automatic detection and identification of new objects with on-line re-scheduling of one of the telescopes for the follow up of new detections. Initial simulations show that it should be possible, weather permitting, to regularly update up to 4000 orbits of Earth-orbiting objects every night.

A joint Polish-Ukrainian astrometric and photometric observing campaign has been performed in January and February of 2017. Several LEO objects were observed using satellite tracking optical sensors from the Astronomical Observatory of Odessa University and the Astronomical Observatory of Adam Mickiewicz University in Poznań. Data series obtained using two different observing, reduction and analysis techniques have been succesfully analysed. Orbital fitting of data from two sensors located on different continents shows consistency at the level of a few arcseconds. The best strategy for future improvements, that should enable the reduction of individual position errors even below 1 arcsec, has been identified. Additionally, a method to estimate the spin parameters of big space debris using fast photometry is presented. There is a collection of 7.5 thousand photometric curves for over 500 objects obtained in the years 2005-2016 in Odessa Observatory. For several inactive satellites the variations of sidereal spin periods and spin axis directions have been determined. In this paper the joint photometric data and the rotation of the big inactive satellites Envisat and Topex/Poseidon were analyzed. The deceleration of Envisat’s rotation during 4 years was studied together with the estimation of its spin axis inclination.

A fall of small objects took place on 27th April 2012 in Wargowo village near Oborniki, about 25 km NW from Poznan (Poland). There was only one eye-witness of the fall, who found two separate pieces (ca. 2.7 cm and ca. 2 cm), with several small additional fragments. After microscopic observations and chemical analysis a meteoritic origin of these objects was excluded. They are identified as space debris, therefore man-made. The most probable source of the observed fall was space debris 35127 Fengyun 1C DEB, created during destruction of the Chinese weather satellite Fengyun-1C (FY-1C). (C) 2017 COSPAR. Published by Elsevier Ltd. All rights reserved.

The increasing number of objects orbiting the earth justifies the great attention and interest in the observation, spacecraft protection, and collision avoidance. These studies involve different disturbances and resonances in the orbital motions of these objects distributed by the distinct altitudes. In this work, objects in resonant orbital motions are studied in low earth orbits. Using the two-line elements (TLE) of the NORAD, resonant angles and resonant periods associated with real motions are described, providing more accurate information to develop an analytical model that describes a certain resonance. The time behaviors of the semimajor axis, eccentricity, and inclination of some space debris are studied. Possible irregular motions are observed by the frequency analysis and by the presence of different resonant angles describing the orbital dynamics of these objects.

Studies show that the number of debris in low Earth orbit is exponentially growing despite future debris release mitigation measures considered. Specifically, the already existing population of small and medium debris (between 1 cm and several dozens of cm) is today a concrete threat to operational satellites. A ground-based laser solution which can remove, at low expense and in a nondestructive way, hazardous debris around selected space assets appears as a highly promising answer. This solution is studied within the framework of the CLEANSPACE project which is part of the FP7 space program. The overall CLEANSPACE objective is: to propose an efficient and affordable global system architecture, to tackle safety regulation aspects, political implications and future collaborations, to develop affordable technological bricks, and to establish a roadmap for the development and the future implantation of a fully functional laser protection system. This paper will present the main conclusions of the CLEANSPACE project.

The paper, in the first part, presents general information about the CLEANSPACE project including the main drivers and requirements. Overall CLEANSPACE objective is to define a global architecture (including surveillance, identification and tracking) for an innovative ground-based laser solution which can remove hazardous medium debris around selected space assets. The CLEANSPACE project is realized by an European consortium in the frame of the European Commission Seventh Framework Programme (FP7). The second part contains exemplary results of the objects orbit changes due to the Laser Debris Removal (LDR) operation for different locations of the LDR station and different parameters of the laser energy and telescope diameter. The future orbit and re-entry parameters are estimated taking into account the influence of all important perturbation factors on the space debris orbital motion after the LDR action.

Since 1957 the number of space debris has been increasing and it cause threat of collision. To calculate precisely space debris orbit we used several perturbations in our force model: geopotential, luni-solar effects, solar radiation pressure and influence of Earth’s atmosphere. For satellites with altitude of perigee higher than 1000 km perturbations from the atmosphere is negligible. However for objects which reaches its lower parts is one of the most important perturbation. For the last perturbation we used NRMLMSISE-00 empirical model to calculate precise parameters for the atmosphere. For large amount of objects using numerical integration there appears to be a problem with time of calculations. For this reason, we decided to use analytical model, which is much faster and more convenient. Due to highly elliptical orbit we had to exchange the eccentricity function by the Hansen coefficients.

The increasing number of objects orbiting the Earth justifies the great attention and interest in the observation, spacecraft protection and collision avoidance. These studies involve different disturbances and resonances in the orbital motions of these objects distributed by the distinct altitudes. In this work, the TLE (Two-Line Elements) of the NORAD are studied observing the resonant period of the objects orbiting the Earth and the main resonance in the LEO region. The time behavior of the semi-major axis, eccentricity and inclination of some space debris are studied. Possible irregular motions are observed by the frequency analysis and by the presence of different resonant angles describing the orbital dynamics of these objects.