Conceptual Study on Laser Networks for Near‐Term Collision Avoidance for Space Debris in the Low Earth Orbit

Due to the increasing amount of space debris, several laser‐based concepts for orbit modification have been proposed in the recent years. Since the sparse availability of pulsed lasers with high energy (> 10 kJ) seems to render laser‐ablative debris nudging for collision avoidance into a solution only for the long run, alternative options which can be realized earlier are mandatory to counter the rapidly increasing number of space debris in low Earth orbit. In this regard, high‐power CW lasers (> 10 kW) have been proposed in the past for debris nudging by photon pressure. With momentum coupling being 3 – 4 orders of magnitude lower than in the case of laser ablation, this might appear as a poor alternative at first glance, but the opposite is the case when a greater number of laser stations are combined forming an international network for laser tracking and momentum transfer (LTMT). From this viewpoint, we report on our findings on photon momentum transfer to space debris from our work performed under the conceptual study LARAMOTIONS (SSA P3‐SST‐XV) funded by the European Space Agency (ESA) in the framework of ESA’s Space Situational Awareness Program. Commercial availability of high power CW lasers allows for the setup of a network of relatively cost‐efficient laser stations in the next decade. Such an LTMT network would serve for both momentum transfer to space debris as well as for high precision laser tracking as a prerequisite for conjunction alert assessment and high‐power laser beam pointing. Depending on the network size, geographical distribution of stations, orbit parameters and remaining time to conjunction, multi‐pass irradiation enhances the efficiency of photon momentum coupling by 1 – 2 orders of magnitude and has the potential to eventually yield a promisingly significant reduction of the collision rate in low Earth orbit

American Gut: an Open Platform for Citizen Science Microbiome Research

McDonald D, Hyde E, Debelius JW, et al. American Gut: an Open Platform for Citizen Science Microbiome Research. mSystems. 2018;3(3):e00031-18

Active Control Loop of the BOROWIEC SLR Space Debris Tracking System

The task of tracking cooperative satellites equipped with laser retroreflectors, by means of Satellite Laser Ranging (SLR), is an issue well described in the literature. The follow-up movement of the ground-based transceiver telescope behind an orbital object is based on the positional ephemeris data. The problem of controlling the follow-up motion of the telescope’s mount mostly in the Az/El configuration in this case boils down to the interpolation of the positional ephemeris data of the orbital object, which is the information input vector for the motion control system of the orthogonal and non-coupled axes of the propulsion system. In the case of tracking and determining the position of uncooperative objects (not equipped with retroreflectors), for which we can include rocket bodies and fragmentary elements, the task of keeping track of them becomes complex. The positional uncertainty of the ephemeris of uncooperative objects obtained mainly by means of survey radar acquisition requires the use of innovative solutions and complex control systems that enable the effective implementation of the tracking process. This paper presents innovative methods for the active control loop used in the SLR technique, consisting of dynamic motion corrections based on the passive optical acquisition with object recognition and analysis of the photon trace scattered from an orbital object

Active Decision Support System for Observation Scheduling Based on Image Analysis at the BOROWIEC SLR Station

The dynamic exploration of the orbits from the LEO-to-GEO region, for the needs of telecommunication services, science, industry and defense, forces monitoring of the trajectory of such orbital objects for the safety of spacecraft traffic and, in the case of deorbitation, for the safety of ground infrastructure. First off all, the need for trajectory monitoring in order to avoid collisions can be distinguished, as well as the need to calibrate the satellite on-board devices. This is mainly carried out by radar measurements, by passive optical acquisition and active laser measurements. The number of orbital objects increases rapidly, and the number of tracking stations for the second is relatively small. This leads to a situation in which each tracking station must select which of the objects will be subject to the measurement task. In the case of the Satellite Laser Ranging (SLR) or passive optical set-up, the weather conditions are an important factor enabling the measurement of the orbital object trajectory. This paper presents an innovative observation scheduling support system based on the analysis of the images obtained from the Allsky camera. The information of the degree of cloud cover, the position of the Sun/Moon in connection with the graphical projections of the ephemeris trajectory of the orbital objects allows increasing the measurement efficiency. The presented solution is part of a larger number of improvements carried out by the author, which lead to the upgrade of SLR stations in terms of new technologies and safety of use

Imitation of a Roman siliqua from Konarzewo near Poznań

An imitation of a Roman siliqua was found during an archaeological survey carried out by the Institute of Prehistory of Poznań University at a settlement from the late Roman period in Konarzewo near Poznań (site 5). The find was discovered in the east part of the settlement, in a culture layer above structure E64 or even in its upper part. A considerable number of sherds were found at this structure and in the vicinity. The beginnings of the settlement are dated from 340 AD using dendrochronology. A cremation burial ground discovered in one of the wells is supposed to have been used from the middle of the fifth century to the middle of the sixth century. The imitation of siliqua is made of .970 silver. It is oval in shape (21 x 18 mm) and weighs 2.916 g. Surprisingly, the Emperor's bust, which was very well copied, is in contrast to totally blundered legends, where the letters are difficult to recognize. Moreover, the reverse is very poorly marked and hardly visible. A heavy siliqua of Constantius II from the years 353-357 with the inscription VOTIS/XXX/ MVLTIS/XXXX, presumably from Sirmium served as the pattern. However, the hairdo is different (Emperors hair is parted at the top of his head to the front and back). It has analogies on Byzantine coins of Justin I and Justinian I. Therefore, there is a possibility that although the imitation found in Konarzewo was influenced by a coin from the fourth century, it was made not earlier than in the sixth century. Other, previously known imitations of siliquae of Constantius II, imitations which had been made earlier, e.g. those from the hoards of Kecel (Romania), Budai (Moldoya) and Laatzen (Germany), look completely different, and this fact weighs in favour of a later chronology. It is also a well-known fact that as regards making ornaments (brooches), Roman coins were also imitated after a considerable passage of time. The imitation discovered in Konarzewo was probably made outside the boundaries of the Empire, but at a relatively small distance, to the north of the Danube. The maker was an artistic illiterate, who remained under the direct influence of Roman culture. His aim was to produce a jewellery rather than a coin. The very poor reproduction of the reverse, which is nearly invisible, argues for this. The non-monetary function of the artefact would be obvious if we were to assume a later date for its manufacture. It was probably a pendant, which was only later turned into a brooch. A strong bend at one edge of the artefact and the punching of two little holes near the other edge argues for a change of function. The holes are situated close to the edge behind the Emperor's head and could not have been cut when the artefact was made or when it served as a pendant. Their purpose may have been to attach a pin and clip mechanism to the brooch (6 figures)

Wariant Delta SARS-CoV-2 – przyczyna kolejnej fali pandemii?

The epidemiological data from progressively more countries indicate a substantial increase in the number of new confirmed cases of SARS-CoV-2 infection despite most of the population being vaccinated. The new SARS-CoV-2 Delta variant, which was first detected in India at the end of 2020, is now the dominant strain responsible for the increase in the number of infections. Currently the Delta variant is responsible for nearly 100% of new cases in the UK, whilst in other countries its contribution to newly identified cases is dynamically rising. According to the prognostics by the end of August 2021 the Delta variant will constitute 90% of all new cases. This new variant is much more transmissible and has less characteristic symptoms than the previous ones, and that facilitates the rapid spread of the virus. The risk of hospitalization and severity of the disease are also higher. Current studies indicate, that complete vaccination effectively prevents from infection with the Delta variant. Efficient testing on a mass scale, especially of individuals with uncharacteristic symptoms and of vaccinated people will be crucial to dampen the next wave.Dane epidemiologiczne z kolejnych państw wskazują na znaczny wzrost nowych potwierdzonych zakażeń SARS-CoV-2 pomimo zaszczepienia znacznej części populacji. Za wzrost liczby zakażeń odpowiedzialny jest głównie nowy wariant Delta SARS-CoV-2, który po raz pierwszy został wyizolowany pod koniec 2020 roku w Indiach. Aktualnie wariant Delta odpowiada za blisko 100 % nowych zakażeń w Wielkiej Brytanii, a w kolejnych krajach jego udział w nowo wykrywanych zakażeniach dynamicznie wzrasta. Według prognoz do końca sierpnia 2021 r. wariant Delta będzie odpowiadał za 90 % nowych zakażeń w Unii Europejskiej. Nowy wariant charakteryzuje się wyższą zakaźnością i mniej specyficznymi objawami niż wcześniejsze warianty wirusa, co sprzyja jego szybkiemu rozprzestrzenianiu w populacji. Wyższe jest także ryzyko ciężkiego przebiegu choroby wymagającego hospitalizacji. Aktualne badania wskazują, że pełne zaszczepienie skutecznie chroni przed zakażeniem wariantem Delta. Kluczowe w ograniczeniu kolejnej fali zakażeń będzie testowanie przeprowadzone na szeroką skalę, również osób z niecharakterystycznymi objawami i zaszczepionych, oraz skuteczna kontynuacja programu szczepień

Measurements to space debris in 2016-2020 by laser sensor at Borowiec Poland

In 2014, a significant upgrade was made to the Borowiec (BORL 7811) laserranging system, which is the part of Space Research Centre of the Polish Academy of Sciences (SRC PAS). Two high-energy lasers modules were installed. First is the EKSPLA PL-2250, used for tracking objects equipped with retroreflectors. Second is the Continuum Surelite III, dedicated to the tracking of space debris without retroreflectors. In 2016, the BORL station joined the space debris tracking laser group and, since then, is tracking systematically inactive/defunct satellites and typical rocket bodies from LEO regime. Today, the BORL is tracking regularly about 80 different space debris objects. The paper presents the activity of the BORL laser station in observations of space debris. The results presented are from years 2016 to 2020. The sum of all passes from this period is almost 2 000, giving over 23 000 normal points. Average root mean square error (RMS) of objects with satellite laser ranging-dedicated (SLR-dedicated) retroreflectors ranges 1.5 cm-14 cm and of objects without SLR-dedicated retroreflectors ranges 8 cm-222 cm

15 years of observation – selected meteorite falls registered in the PFN in 2004–2019

The Polish Fireball Network (PFN) associated in Comets and Meteors Workshop monitors the sky over Poland regularly for 15 years and registers the bright fireballs over the whole country (Olech 2006; Wiśniewski 2017). Every year we observe a few meteorite falls but due to weather conditions some data are not sufficient for proper strewnfield calculations. In the collaboration with the European Fireball Network the whole territory of Poland is monitored almost regardless of the weather. The publication describes the bolide phenomena characterized by distinctive meteorite falls, so the strewnfield indicated here should become the target of further exploration expeditions

Report on meteorite field search within PFN in 2016/2017 season

The Meteorite Section was created in 2010 on demand of Polish Fireball Network (PFN) for the meteorite searching and investigation purposes. The main task of the Section is to find the meteorites dropped from bolides registered by the Polish Fireball Network. Each year, the PFN registers several meteorite falls within our country and meteorite strewnfield inspections must be carried out at least for the masses of above 300 g estimated with the PyFN software. Only last year the PFN organized several search campaigns. Two of them are presented in the publication