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Mini-EUSO is part of the JEM-EUSO program and operates on board the International Space Station (ISS). It is a UV-telescope with single-photon counting capability looking at nighttime downwards to the Earth through a nadir-facing UV-transparent window. As part of the pre-flight tests, the Mini-EUSO engineering model, a telescope with 1/9 of the original focal surface and a lens of 2.5 cm diameter, has been built and tested. Tests of the Mini-EUSO engineering model have been made in laboratory and in open-sky conditions. Laboratory tests have been performed at the TurLab facility, located at the Physics Department of the University of Turin, equipped with a rotating tank containing different types of materials and light sources. In this way, the configuration for the observation of the Earth from space was emulated, including the Mini-EUSO trigger schemes. In addition to the qualification and calibration tests, the Mini-EUSO engineering model has also been used to evaluate the possibility of using a JEM-EUSO-type detector for applications such as observation of space debris. Furthermore, observations in open-sky conditions allowed the studies of natural light sources such as stars, meteors, planets, and artificial light sources such as airplanes, satellites reflecting the sunlight, and city lights. Most of these targets could be detected also with Mini-EUSO. In this paper, the tests in laboratory and in open-sky conditions are reported, as well as the obtained results. In addition, the contribution that such tests provided to foresee and improve the performance of Mini-EUSO on board the ISS is discussed.

Determining the chelicerate tree of life has been the subject of much research, with deep phylogenetic divergences and high evolutionary rates complicating both morphological and molecular approaches (Noah et al., 2020; Ontano et al., 2021; Sharma et al., 2021; Ballesteros et al., 2022). Within Acari, similar challenges exist—even the basic question of whether Acari is mono- or diphyletic remains unresolved (Pepato & Klimov, 2015; Lozano-Fernandez et al., 2019; Van Dam et al., 2019; Ontano et al., 2021). Several recent molecular studies have attempted to resolve these issues using large multi-gene datasets (Pepato et al., 2022; Klimov et al., 2018), mitochondrial genomes (Ban et al., 2022), and transcriptomes (Lozano-Fernandez et al., 2019). Ultraconserved elements (Faircloth et al., 2012) have recently shown great promise for constructing phylogenies for both deeply- and shallowly-diverged taxa (Zhang et al., 2019), including for Chelicerata (Starrett et al., 2017) and for Arrenuridae within Acari (Shoop, 2019), but have not yet been used across the Acari.

International audience; To take up the challenge of understanding the origin of the ultra-high-energy cosmic rays (UHECRs), new observational means appear necessary. The JEM-EUSO Collaboration has undertaken to open the space road to UHECR studies. For more than a decade, it has been developing a realistic program to measure the UHECRs from space with unprecedented aperture, together with complementary scientific objectives in a broader multidisciplinary context. Several intermediate missions have already been completed (on the ground: EUSO-TA; under stratospheric ballons: EUSO-Balloon and EUSO-SPB1; in space: TUS, and on-board the ISS: MINI-EUSO), and others are in preparation for flight (EUSO-SPB2), under review (K-EUSO: currently on hold), or proposed for the next decade (POEMMA). We report on the general status of the JEM-EUSO program, underlining that its technology has now reached operational maturity, and is ready for actual cosmic-ray shower detection from above.

International audience; Mini-EUSO is the first mission of the JEM-EUSO program on board the International Space Station. It was launched in 2019 and it is currently located in the Russian section (Zvezda module) of the station and viewing our planet from a nadir-facing UV-transparent window. The instrument is based on the concept of the original JEM-EUSO mission and consists of an optical system employing two Fresnel lenses and a focal surface composed of 36 Multi-Anode Photomultiplier tubes, 64 channels each, for a total of 2304 channels with single photon counting sensitivity and an overall field of view of 44° × 44°. Mini-EUSO can map the night-time Earth in the near UV range (predominantly between 290 nm and 430 nm), with a spatial resolution of about 6.3 km and different temporal resolutions of 2.5 µ, 320 µs and 41 ms. Mini-EUSO observations are extremely important to better assess the potential of a space-based detector in studying Ultra-High Energy Cosmic Rays (UHECRs) such as K-EUSO and POEMMA. In this contribution we focus the attention on UV measurements, the observation of clouds and of certain categories of events that Mini-EUSO triggers with the shortest temporal resolution. We place them in the context of UHECR observations from space, namely the estimation of exposure and sensitivity to Extensive Air Showers.

A new species of phytoseiid mites, Neoseiulus neoagrestis sp. nov., was described based on all ontogenetic stages and extensive comparison with types/vouchers of closely related species and a thorough analysis of GenBank data. Mite specimens were collected in an area at the eastern coast of the Black Sea of Russia and cultured. Molecular barcoding revealed a close match (100–99.25%) with several unidentified COX1 sequences from Canada. Both Canadian and Russian mites reproduced sexually and had consistent morphology, including the presence of gd2 gland pores, indicating that they belong to a single species, N. neoagrestis sp. nov. The presence of gd2 gland pores distinguishes N. neoagrestis sp. nov. from a closely related, parthenogenetic species N. agrestis (Karg), which lacks gd2 gland pores. Despite having an arguably negligible morphological difference, these two species were clearly distinct by COX1 sequences (19.95–22.01% K2P distances). We studied the ontogeny of N. neoagrestis sp. nov. and provided comparison with related Neoseiulus species. Furthermore, our examination of types of N. agrestis, N. salish, and N. striatus indicated that the latter two species are potential junior synonyms of N. agrestis.

A technique is proposed for carrying out flight calibration of a photomultiplier tubes (PMTs) of the photodetector in the orbital TUS detector of ultra-high-energy cosmic rays in the absence of a calibration signal. The new technique consists in calculating two statistical characteristics of digitized signals from detected events (their mean value A and variance $$\sigma _{A}^{2}$$ ) and constructing the linear approximation $$\sigma _{A}^{2}$$ (A) for stationary signals. This technique has been tested in a laboratory experiment with a photodetector module, which is identical to the modules used in the detector. As a result, the gains of most photodetector channels of the TUS detector have been estimated again and the changes that occurred (in particular, the “aging effect”) have been analyzed.

The SINP MSU is implementing a program to create compact detectors for studying the atmosphere and near-Earth space from small spacecrafts of the Cubesat type. Within the framework of this program, the AURA detector of ultraviolet radiation of the Earth’s atmosphere described in this article has been developed and tested. The device is a four-channel photometer based on silicon photomultiplier from the SensL Co. Its compactness, low supply voltage, and durability are the factors that determine the advantages for its use in nanosatellites.

The Moscow University Universat-SOCRAT program is aimed at using small satellites to monitor space threats, such as radiation in near-earth space, electromagnetic transients, and potentially dangerous bodies of natural and artificial origins. The first stage of the program implementation began on July 5, 2019 as a result of the successful launch of three Cubesat-type nanosatellites from the Vostochny cosmodrome. These satellites are equipped with instruments for space radiation monitoring, as well as prototypes of devices for observing transient phenomena in the Earth’s atmosphere. In particular, two satellites are equipped with scintillation phosphich detectors that detect charged particles and gamma quanta in the energy release range of 0.1–2 MeV. The geometric factor of these instruments is $${\approx}50$$ cm $${}^{2}$$ sr. One of the Cubesats also carries an optical photometer, consisting of four silicon photomultipliers, which entrance windows are covered with different light filters. The satellites were launched into solar-synchronous orbits with an altitude of $${\approx}550$$ km. This makes favorable conditions for space radiation monitoring in various areas of near-Earth space, including zones of trapped radiation, areas of precipitation, etc. Such an orbit also allows observations of flare phenomena both in the equatorial atmosphere and at high latitudes. The first results of flight tests are discussed.

A procedure for the in-flight calibration of the TUS photoreceiver is proposed and implemented, based on an analysis of stationary signal fluctuation. The procedure is tested using a laboratory mockup. New estimates of the gain are obtained for most TUS channels, and the changes that occur are analyzed.

Tracking Ultraviolet Setup (TUS) detector is a detector of ultraviolet (UV) radiation of the atmosphere in the wavelength range of 300–400 nm (near-ultraviolet) with high sensitivity (tens of photons emitted within the solid angle of 10–4 sr in 0.8 μs), which operated for a year and a half aboard the Lomonosov satellite. The TUS telescope had a multipurpose operational program, which made it possible to detect UV flashes from the shortest ones created by extensive air showers generated by cosmic rays to long ones, up to 1 s, created by meteors. Among these various phenomena, most often are flashes from lightning strikes, both directly creating a glow and causing the development of secondary discharges in the atmosphere, in the upper atmosphere and in the ionosphere. These discharges differ in both nature and phenomenology—in particular, they have different durations and luminosities.

Mini-EUSO is an imaging detector launched on the International Space Station on August 2019 with an unmanned Soyuz spacecraft. It is observing the Earth in a multispectral range comprising UV (300–400 nm), visible (400–780 nm) and NIR (1500–1600 nm). Mini-EUSO is accommodated on board the Russian Zvezda module, facing on a UV-transparent window in Nadir direction. The telescope main optics comprise two Fresnel lenses focusing light onto an array of 36 Hamamatsu multi-anode photomultiplier tubes, each of 64 channels for a total of 2304 pixels. In addition to the two ancillary cameras, Mini-EUSO contains an 8 × 8 array of Multi-Pixel Photon Counter SiPM. The Mini-EUSO main research objectives are the study of Ultra High Energy Cosmic Rays above 1021 eV and the search for Strange Quark Matter, even though, with its large field of view (44°), it will map an Earth ground area of 263 × 263 km2 every 2.5 µs, allowing to study several atmospheric event such as Transient Luminous Event (TLEs), meteoroids and marine bioluminescence.

Mini-EUSO is a new space-based experiment designed primarily to observe showers that develop in atmosphere due to the interaction between molecular nitrogen and Ultra High Energy Cosmic particles (above 1021 eV) crossing by. It belongs to the JEM-EUSO program, which includes several past experiments all devoted to develop new larger size satellite detectors like K-EUSO and POEMMA for future UHEC Rays study from space. Mini-EUSO is a multiwavelenght telescope launched on August 2019 with the unmanned Soyuz MS-14 rocket to the International Space Station and currently operating on board the Russian Zvezda module, facing a UV-transparent window watching Earth in Nadir direction. The telescope optics comprise a main detection system employing two double-sided Fresnel lenses focusing UV (300–400 nm) light onto an array of 36 Hamamatsu Multi-Anode PhotoMultiplier Tubes, each of 64 channels for a total of 2304 pixels working in single photon counting mode, providing a wide field of view (44°) correpsonding to a ground area of 263 x 263 km2 with a highly fast time resolution up to few microseconds. Mini-EUSO includes also multiple ancillary sensors such as visible (400–780 nm) and NIR (1500–1600 nm) cameras covering a wide range of radiation wavelenght as well as a 64 channels Multi-Pixel Photon Counter Silicon PhotoMultiplier array which will increase the Technology Readiness Level of this ultrafast imaging sensor. Beside the primary objective, the mission aims to study different event such as meteoroids, Transient Luminous Event, search for Strange Quark matter and thanks to its space-time resolution is capable to provide UV Earth maps over the surface covered during ISS orbits. In this work we will present the detector integration, the qualification measurements on ground and some preliminary data.

Mini-EUSO is a small orbital telescope with a field of view of $44^{\circ}\times 44^{\circ}$, observing the night-time Earth mostly in 320-420 nm band. Its time resolution spanning from microseconds (triggered) to milliseconds (untriggered) and more than $300\times 300$ km of the ground covered, already allowed it to register thousands of meteors. Such detections make the telescope a suitable tool in the search for hypothetical heavy compact objects, which would leave trails of light in the atmosphere due to their high density and speed. The most prominent example are the nuclearites -- hypothetical lumps of strange quark matter that could be stabler and denser than the nuclear matter. In this paper, we show potential limits on the flux of nuclearites after collecting 42 hours of observations data., Comment: To be published in the Proceedings of the 37th International Cosmic Ray Conference (ICRC 2021), Berlin, 12 -23 July 2021

The K-EUSO project developed in the JEM-EUSO collaboration for installation on board the International Space Station is described. A number of technological projects are successfully executed during its preparation: the EUSO-Balloon and EUSO-SPB1 balloon experiments, and the telescope as part of the Telescope Array (EUSO-TA). Since 2019, a wide-angle detector “UV atmosphere” (Mini-EUSO) has been operating on board the ISS Russian Segment. After K-EUSO, it is planned to conduct the even more ambitious POEMMA (Probe of Extreme Multi-Messenger Astrophysics) experiment to register both ultra-high energy cosmic rays (UHECR) and high-energy neutrinos.

Eriophyoid mites are ancient and widely distributed microscopic plant symbionts, with 4,400 nominal species. Some eriophyoid mites can induce galls in their plant hosts, but the mechanism of gall induction is not well understood. One hypothesis suggests that associated bacteria may enhance the production of phytohormones by gall-inducing arthropods. The phylogenetic position of Eriophyoidea is also a contentious issue.

Mini-EUSO is a detector observing the Earth in the ultraviolet band from the International Space Station through a nadir-facing window, transparent to the UV radiation, in the Russian Zvezda module. Mini-EUSO main detector consists in an optical system with two Fresnel lenses and a focal surface composed of an array of 36 Hamamatsu Multi-Anode Photo-Multiplier tubes, for a total of 2304 pixels, with single photon counting sensitivity. The telescope also contains two ancillary cameras, in the near infrared and visible ranges, to complement measurements in these bandwidths. The instrument has a field of view of 44 degrees, a spatial resolution of about 6.3 km on the Earth surface and of about 4.7 km on the ionosphere. The telescope detects UV emissions of cosmic, atmospheric and terrestrial origin on different time scales, from a few 𝜇s upwards. On the fastest timescale of 2.5 𝜇s, Mini-EUSO is able to observe atmospheric phenomena as Transient Luminous Events and in particular the ELVES, which take place when an electromagnetic wave generated by intra-cloud lightning interacts with the ionosphere, ionizing it and producing apparently superluminal expanding rings of several 100 km and lasting about 100 𝜇s. These highly energetic fast events have been observed to be produced in conjunction also with Terrestrial Gamma-Ray Flashes and therefore a detailed study of their characteristics (speed, radius, energy ...) is of crucial importance for the understanding of these phenomena. In this paper we present the observational capabilities of ELVE detection by Mini-EUSO and specifically the reconstruction and study of ELVE characteristics.

Mini-EUSO is the first detector of the JEM-EUSO program deployed on the ISS. It is a wide field of view telescope currently operating from a nadir-facing UV-transparent window on the ISS. It is based on an array of MAPMTs working in photon counting mode with a 2.5 μs time resolution. Among the different scientific objectives it searches for light signals with time duration compatible to those expected from Extensive Air Showers (EAS) generated by EECRs interacting in the atmosphere. Although the energy threshold for cosmic ray showers is above $E > 10^{21} eV$, due the constraints given by the size of the UV-transparent window, the dedicated trigger logic has been capable of the detection of other interesting classes of events, like elves and ground flashers. An overview of the general performance of the trigger system is provided, with a particular focus on the identification of classes of events responsible for the triggers.

The TUS detector is the first orbital telescope designed to test techniques for measuring ultraviolet fluorescence and Cherenkov radiation of extensive air showers (EASes). The detector was launched aboard the Lomonosov satellite on April 28, 2016. A two-level event selection system (trigger) was developed and implemented in the digital electronics of the photodetector. This trigger was optimized for the search for EASes, but at the same time operated under conditions of variable atmospheric luminescence of both natural (aurora light, diffused moonlight, thunderstorm phenomena) and anthropogenic origin (city lights, flashes at airports). The frequency of the trigger also depends on that of transient atmospheric phenomena of different origin. Examples of events recorded by the TUS detector and selected welve by the EAS trigger are given.

We present concept of a new multi-satellite Universat-SOCRAT project aimed to study transient phenomena in the upper atmosphere such as transient luminous events (TLEs) and terrestrial gamma-ray flashes (TGFs). It is a new space project of Lomonosov Moscow State University based on the use of a few satellites in the near-Earth orbit for real-time monitoring of radiation environment, natural (asteroids, meteoroids) and artificial (space debris) potentially dangerous objects, electromagnetic transients including cosmic gamma-ray bursts, terrestrial gamma-ray flashes, and optical and ultraviolet bursts in the Earth’s atmosphere.Study of TLEs and TGFs remains an important and demanding task despite of a multitude of recently acquired data for these phenomena. This might be explained by the absence of comprehensive theoretical understanding of physical nature of high-energy processes in the Earth’s atmosphere. Multi-wavelength synchronous observations with moderate accuracy of localization of TGF and TLE events are necessary to gain an insight of physics governing these high-energy processes in the Earth’s atmosphere. In the article, we present results of TLE observations in space experiments of Moscow State University and discuss advanced instruments for optical observations of TLEs, as well as gamma-ray burst monitor and tracking gamma spectrometer for TGFs observations.

The Probe Of Extreme Multi-Messenger Astrophysics (POEMMA) is designed to accurately observe ultra-high-energy cosmic rays (UHECRs) and cosmic neutrinos from space with sensitivity over the full celestial sky. POEMMA will observe the extensive air showers (EASs) from UHECRs and UHE neutrinos above 20 EeV via air fluorescence. Additionally, POEMMA will observe the Cherenkov signal from upward-moving EASs induced by Earth-interacting tau neutrinos above 20 PeV. The POEMMA spacecraft are designed to quickly re-orientate to follow up transient neutrino sources and obtain unparalleled neutrino flux sensitivity. Developed as a NASA Astrophysics Probe-class mission, POEMMA consists of two identical satellites flying in loose formation in 525 km altitude orbits. Each POEMMA instrument incorporates a wide field-of-view (45$^\circ$) Schmidt telescope with over 6 m$^2$ of collecting area. The hybrid focal surface of each telescope includes a fast (1~$\mu$s) near-ultraviolet camera for EAS fluorescence observations and an ultrafast (10~ns) optical camera for Cherenkov EAS observations. In a 5-year mission, POEMMA will provide measurements that open new multi-messenger windows onto the most energetic events in the universe, enabling the study of new astrophysics and particle physics at these otherwise inaccessible energies., Comment: 66 pages, 53 figures; JCAP accepted version

The TUS detector was the first space-based mission aimed for ultra-high-energy cosmic ray (UHECR) measurements. The detector was designed to register the fluorescent signal of extensive air showers (EAS) developing in the night atmosphere of Earth in the UV range of 300-400 nm. TUS was launched on board the Lomonosov satellite in April, 2016 and operated till December, 2017. Almost 90 thousand events were recorded during the mission, among them lightning discharges, meteors, transient luminous events, polar lights and anthropogenic signals. Some puzzling bright UV flashes in a clear sky far from possible artificial sources were also registered. Besides this, a number of EAS candidates were found in the TUS database. The majority of candidates analysed so far were recorded above populated areas near airports or similar objects, and the energy of the signals corresponds to at least 1 ZeV if they were generated by an UHECR, which does not allow one to consider these events as UHECRs. We briefly present the main results of the TUS experiment and discuss its importance for the development of the future orbital missions., Comment: Proceedings of the 37th International Cosmic Ray Conference (ICRC 2021), Berlin, Germany

TUS (Tracking Ultraviolet Set-up) was the world's first orbital detector aimed at testing the principle of observing ultra-high energy cosmic rays (UHECRs) with a space-based fluorescence telescope. TUS was launched into orbit on 28th April 2016 as a part of the scientific payload of the Lomonosov satellite, and its mission continued for 1.5 years. During this time, its exposure reached $\sim1550$ km$^2$ sr yr for primary energy $\gtrsim400$ EeV, and a number of extensive air showers-like events were registered. The shape and kinematics of the signal in these events closely resembled those expected from UHECRs but amplitudes of the signal and some other features were in contradiction with this assumption. A detailed analysis of one of EAS-like events (TUS161003) revealed that a primary cosmic ray would need to have an energy $\gtrsim1$ ZeV in order to produce a light curve of the observed amplitude, which is incompatible with the cosmic ray spectrum obtained with ground-based experiments. More than this, the slant depth of the shower maximum be the signal produced by a cosmic particle, was estimated as $\lesssim500$ g/cm$^2$, which corresponds to cosmic rays around 1 PeV. We present a preliminary discussion of a hypothesis that the TUS161003 event and perhaps some other bright EAS-like events could be produced by relativistic dust grains, which were considered a possible component of the cosmic ray flux beyond the GZK cut-off some time ago., Comment: Proceedings of the 37th International Cosmic Ray Conference (ICRC 2021), Berlin, Germany

International audience; Mini-EUSO is a mission of the JEM-EUSO program flying onboard the International Space Station since August 2019. Since the first data acquisition in October 2019, more than 35 sessions have been performed for a total of 52 hours of observations. The detector has been observing Earth at night-time in the UV range and detected a wide variety of transient sources all of which have been modeled through Monte Carlo simulations. Mini-EUSO is also capable of detecting meteors and potentially space debris and we performed simulations for such events to estimatetheir impact on future missions for cosmic ray science from space. We show here examples of the simulation work done in this framework to analyze the Mini-EUSO data. The expected response of Mini-EUSO with respect to ultra high energy cosmic ray showers has been studied. The efficiency curve of Mini-EUSO as a function of primary energy has been estimated and the energy threshold for Cosmic Rays has been placed to be above $10^{21}$ eV. We compared the morphology of several transient events detected during the mission with cosmic ray simulations and excluded that they can be due to cosmic ray showers. To validate the energy threshold of the detector, asystem of ground based flashers is being used for end-to-end calibration purposes. We therefore implemented a parameterization of such flashers into the JEM-EUSO simulation framework and studied the response of the detector with respect to such sources.

Mini-EUSO is a telescope observing the Earth in the ultraviolet band from the International Space Station. It is a part of the JEM-EUSO program, paving the way to future larger missions, such as KEUSO and POEMMA, devoted primarily to the observation of Ultra High Energy Cosmic Rays from space. Mini-EUSO is capable of observing Extensive Air Showers generated by Ultra-High Energy Cosmic Rays with an energy above 10^21 eV and detect artificial showers generated with lasers from the ground. Other main scientific objectives of the mission are the search for nuclearites and Strange Quark Matter, the study of atmospheric phenomena such as Transient Luminous Events, meteors and meteoroids, the observation of sea bioluminescence and of artificial satellites and man-made space debris. Mini-EUSO will map the night-time Earth in the UV range (290 - 430 nm), with a spatial resolution of about 6.3 km and a temporal resolution of 2.5 microseconds, through a nadir-facing UV-transparent window in the Russian Zvezda module. The instrument, launched on August 22, 2019 from the Baikonur cosmodrome, is based on an optical system employing two Fresnel lenses and a focal surface composed of 36 Multi-Anode Photomultiplier tubes, 64 channels each, for a total of 2304 channels with single photon counting sensitivity and an overall field of view of 44 degrees. Mini-EUSO also contains two ancillary cameras to complement measurements in the near infrared and visible ranges. In this paper we describe the detector and present the various phenomena observed in the first months of operations., 23 pages, 20 figures

Mini-EUSO is a very wide (44°x44°) field of view telescope installed on August 2019 inside the Zvezda Module of the ISS, looking nadir through a UV transparent window and taking data since October 2019. Its optical system consists of two Fresnel lenses, focusing the light onto an array of 36 multi-anode photomultiplier tubes. The focal surface counts a total of 2304 pixels, each one having a footprint of about 6.5 km on ground. The instrument triggers on two different timescales, respectively 2.5 μs (D1) and 320 μs (D2), and perform a continuous monitoring of the UV emission at a 40.96 ms timescale (D3). At time of writing, about one thousand meteors on D3 data have been classified as meteors using our current detection algorithm. We describe here a concept of an alternative algorithm to recognize meteors in the D3 continuous data-stream, which can be also implemented in the future for online triggering, and show some examples of detected meteors by our instrument. We also performed a search of possible coincident detections of Mini-EUSO meteors by ground meteor and fireball networks, such as PRISMA in Italy, to gain a stereoscopic vision of the event itself. In light of these initial results, we present here the capabilities of Mini-EUSO instrument in meteor science.

The results of experiments onboard the Lomonosov satellite on observing natural and technogenic space hazards including electromagnetic transients and space debris are discussed. A new space project Universat-SOCRAT being developed by Moscow State University is also discussed. The project aims to create a constellation of small satellites for real-time monitoring of the radiation environment and potentially hazardous objects of natural (asteroids, meteoroids) and technogenic origin (space debris) in near-Earth space, and such phenomena as cosmic and atmospheric gamma-ray bursts and optical and ultraviolet radiation flashes from Earth’s atmosphere.

The Mini-EUSO instrument is a UV telescope to be placed inside the International Space Station (ISS), looking down on the Earth from a nadir-facing window in the Russian Zvezda module. Mini-EUSO will map the earth in the UV range (300 - 400 nm) with a spatial resolution of 6.11km and a temporal resolution of 2.5 $\mu$s, offering the opportunity to study a variety of atmospheric events such as transient luminous events (TLEs) and meteors, as well as searching for strange quark matter and bioluminescence. Furthermore, Mini-EUSO will be used to detect space debris to verify the possibility of using a EUSO-class telescope in combination with a high energy laser for space debris remediation. The high-resolution mapping of the UV emissions from Earth orbit allows Mini-EUSO to serve as a pathfinder for the study of Extreme Energy Cosmic Rays (EECRs) from space by the JEM-EUSO collaboration., Comment: 29 pages, 11 figures. Accepted by ASR

Usually a thunderstorm region with lightning activity is necessary for the formation of known types of upper atmospheric transient luminous events (TLEs: sprites, emission of light and very low frequency perturbation, blue jets, etc.) with well-recognizable visible emissions. However, some “far-from-thunderstorm” transient events have been detected in some experiments. Measurements of transient atmospheric events (TAEs) were made on board the Vernov satellite by the sensitive UV and IR detector. Remote observation from the satellite’s orbit provided measurements all over the globe and allowed us to study events associated with thunderstorms (lightning, TLEs) and unusual UV flashes (UV TAEs) far from thunderstorm regions. More than 8500 UV TAEs were measured by the Vernov satellite over the globe. Forty seven far-from-thunderstorm TAEs were selected having no lightning discharges during 1 h in a radius of 1000 km around the location of the event according to the Worldwide Lightning Location Network (WWLLN) and Vaisala Global Lightning Data Set (GLD360) data. Special attention was given to six events with complicated temporal structure and low luminosity in the IR channel. Their properties and atmospheric conditions were studied in detail. The analysis of cloud cover in addition to the lightning location networks data demonstrated the low probability of any lightning in the region of measurements.

The new space project of M. V. Lomonosov Moscow State University on elaboration of multiple satellites for real time monitoring in the near-Earth space of radiation environment, natural (asteroids, meteoroids) and artificial (space debris) potentially dangerous objects, electromagnetic transients, such as cosmic gamma ray bursts, terrestrial gamma ray flashes, optical and ultraviolet bursts in the Earth atmosphere is presented. It is intended to install on the satellites the following instruments for space monitoring of dangerous objects and hazards: spectrometers of electrons and protons, complex of instruments for study of transient electromagnetic phenomena including gamma ray spectrometer, detectors of ultraviolet and optical emission and wide-field optical cameras. Successful implementation of the project for the first time in the world allows realization of a space system prototype for monitoring and preventing of space hazards for both ongoing and planned space missions, and also for aircraft flying in the upper atmosphere. There are also discussed results of experiments on-board Lomonosov in view of good experience of wide field camera use for monitor observations in space. These results formed the base of scientific program for the new project Universat- SOCRAT.

An orbital detector of ultra-high energy cosmic rays has been developed by the Skobel’tsyn Institute of Nuclear Physics of the Moscow State University together with the international JEM-EUSO collaboration for mounting on board the International Space Station. Its multichannel photodetector is composed of an array of multianode photomultiplier tubes (MAPMTs) combined into modules with 36 MAPMTs in each and with approximately 105 pixels in total. Since the number of channels is great and the speed of measurements is high, high requirements are set for the system of detection, selection, and analysis of events. The designs of the modular photodetector composition and the network architecture of the data processing system that is capable of performing efficient selection of events with different space−time structures are presented. The network principle is implemented via three types of communications: high-speed links between adjacent photodetector modules, long-distance communications for recording information to the permanent memory, and synchronizing links for timing the operation of individual modules. This digital-processing system of the detector can be designed using the ZYNQ system-on-chip concept that includes a field programmable gate array and a processor system.

In this paper, data obtained by the Vernov satellite are discussed in comparison with the data obtained by Universitetsky–Tatiana-1, 2 satellites. The advanced instrumentation onboard the Vernov satellite improved the capabilities of the data-transmission system, providing an opportunity to acquire more detailed information on transient atmospheric events (TAEs), including a wider range of TAE photon numbers (event brightness) down to lower photon numbers, the opportunity to observe the events in ultraviolet range without the considerable inclusion of red–infrared photons (which indicates the substantial contribution of electric discharges, lightning precursors, at the altitudes of thunderstorm clouds), and the observation of TAE series at a rate of about 10–100 occurrences per second with a period from tens of seconds to several minutes.

Data on transient atmospheric events (TAEs) were obtained from the Vernov satellite and are presented in this paper. The data are considered in conjunction with previous data obtained by the Universitetsky-Tatiana-1 and Universitetsky-Tatiana-2 satellites. The larger volume of stored scientific data in the Vernov mission and its advanced ultraviolet (UV) and red–infrared (R–IR) radiation detector (DUV) measurements allowed improved TAE-distribution data to be obtained over a wide range of photon numbers. The difference between features of luminous transients and “dim” transients, measured by the Universitetsky-Tatiana-2 satellite, is confirmed by Vernov’s data. There are also interesting dim UV events with no R–IR radiation. Such events are expected to be deep in the atmosphere at the level of thunderstorm clouds. They might be radiated by electric discharges of less power than lightning; in fact, at the preliminary stage of lightning. The observation of repeating dim TAEs in various time intervals, starting from tens of milliseconds and up to minutes, indicates that thunderstorm electric activity is much more variable than pure lightning strikes.

The RELEС scientific payload of the Vernov satellite launched on July 8, 2014 includes the DRGE spectrometer of gamma-rays and electrons. This instrument comprises a set of scintillator phoswich-detectors, including four identical X-ray and gamma-ray detector with an energy range of 10 kev to 3 MeV with a total area of ~500 cm2 directed to the atmosphere, as well as an electron spectrometer containing three mutually orthogonal detector units with a geometric factor of ~2 cm2 sr. The aim of a space experiment with the DRGE instrument is the study of fast phenomena, in particular Terrestrial gamma-ray flashes (TGF) and magnetospheric electron precipitation. In this regard, the instrument provides the transmission of both monitoring data with a time resolution of 1 s, and data in the event-by-event mode, with a recording of the time of detection of each gamma quantum or electron to an accuracy of ~15 μs. This makes it possible to not only conduct a detailed analysis of the variability in the gamma-ray range, but also compare the time profiles with the results of measurements with other RELEC instruments (the detector of optical and ultraviolet flares, radio-frequency and low-frequency analyzers of electromagnetic field parameters), as well as with the data of ground-based facility for thunderstorm activity. This paper presents the first catalog of Terrestrial gamma-ray flashes. The criterion for selecting flashes required in order to detect no less than 5 hard quanta in 1 ms by at least two independent detectors. The TGFs included in the catalog have a typical duration of ~400 μs, during which 10–40 gamma-ray quanta were detected. The time profiles, spectral parameters, and geographic position, as well as a result of a comparison with the output data of other Vernov instruments, are presented for each of candidates. The candidate for Terrestrial gamma-ray flashes detected in the near-polar region over Antarctica is discussed.

The TUS space experiment is aimed at studying energy and arrival distribution of UHECR at E > 7 × 1019 eV by using the data of EAS fluorescent radiation in atmosphere. The TUS mission was launched at the end of April 2016 on board the dedicated “Lomonosov” satellite. The TUSSIM software package has been developed to simulate performance of the TUS detector for the Fresnel mirror optical parameters, the light concentrator of the photo detector, the front end and trigger electronics. Trigger efficiency crucially depends on the background level which varies in a wide range: from 0.2 × 106 to 15 × 106 ph/( m 2 μ s sr) at moonless and full moon nights respectively. The TUSSIM algorithms are described and the expected TUS statistics is presented for 5 years of data collection from the 500 km solar-synchronized orbit with allowance for the variability of the background light intensity during the space flight.