B. A. Khrenov

First results of investigating the space environment onboard the Universitetskii-Tatyana satellite

The complex of scientific pay load installed onboard the research and educational Universitetskii-Tatyana microsatellite of Moscow State University is described. The complex is designed to study charged particles in the near-earth space and ultraviolet emissions of the atmosphere. Data of the measurements of charged particle fluxes in the microsatellite orbit are presented, spectra are calculated, and the dynamics of penetration boundaries for protons of solar cosmic rays (SCR) during geomagnetic disturbances in 2005 is investigated. Intensities of the ultraviolet emission are measured in the entire range of variation of the atmospheric irradiation, as well as intensities of auroras in the polar regions of the Northern and Southern hemispheres. The experimental data on flashes of ultraviolet radiation (transient light phenomena in the upper atmosphere) are considered, and some examples of oscillograms of their temporal development and their distribution over geographical coordinates are presented.

Investigations of the space environment aboard the Universitetsky-Tat’yana and Universitetsky-Tat’yana-2 microsatellites

The first results obtained through the university small satellites program developed at Moscow State University (MSU) are presented. The space environment was investigated aboard two MSU microsatellites designed for scientific and educational purposes, Universitetsky-Tat’yana and Universitetsky-Tat’yana-2. The scientific equipment is described to study charged particles in near Earth space and atmospheric radiations in ultraviolet, red, and infrared optical wavelength ranges. The dynamic properties of fluxes of charged particles in microsatellite orbits are studied and findings are presented regarding specific parameters of solar proton penetration during the geomagnetic disturbances. Experimental results are considered concerning flashes of ultraviolet (UV), red (R), and infrared (IR) radiation that are transient light phenomena in the upper atmosphere. The space educational MSU program developed on the basis of the Universitetsky-Tat’yana projects is reviewed.

Ultraviolet radiation detector of the MSU research educational microsatellite Universitetskii-Tat’yana

An optical detector that is part of the research equipment system installed aboard the MSU research educational microsatellite Universitetskii-Tat’yana and intended to study the atmosphere in the ultraviolet spectrum is described. The important advantage of the detector is that it can record time profiles of glow intensity in a wide range of durations. Examples of measuring atmospheric radiation intensities and oscillograms of flashes recorded by the detector are given.

Ultraviolet flashes in the equatorial region of the Earth

Intense ultraviolet flashes with a duration of 1 to 64 ms have been detected by the UV detector (wavelengths 300–400 nm) that operates at the Universitetsky-Tatiana MSU satellite. Most flashes occur in the equatorial region of the Earth. The nature of the observed flashes is discussed.

The JEM-EUSO Mission

The JEM‐EUSO mission explores the origin of the extreme energy cosmic rays (EECRs) above 100 EeV and explores the limits of the fundamental physics, through the observations of their arrival directions and energies. It is designed to achieve an exposure larger than 1 million km2 sr year at the highest energies to open a new particle astronomy channel. This super‐wide‐field of view (60 degrees) telescope with a diameter of about 2.5 m looks down from space onto the night sky to detect near UV photons (330–400 nm, both fluorescent and Cherenkov photons) emitted from the giant air showers produced by EECRs. The arrival direction map with more than five hundred events after just the three years will tell us the origin of the EECRs, allow us to identify the nearest EECR sources with known astronomical objects, which can afterwards be examined in other astronomical channels. This is likely to lead to an understanding of the acceleration mechanisms perhaps producing discoveries in astrophysics and fundamental ph...

Global anisotropy of arrival directions of ultra-high-energy cosmic rays: capabilities of space-based detectors

Planned space-based ultra-high-energy cosmic-ray detectors (TUS, JEM-EUSO and S-EUSO) are best suited for searches of global anisotropies in the distribution of arrival directions of cosmic-ray particles because they will be able to observe the full sky with a single instrument. We calculate quantitatively the strength of anisotropies associated with two models of the origin of the highest-energy particles: the extragalactic model (sources follow the distribution of galaxies in the Universe) and the superheavy dark matter model (sources follow the distribution of dark matter in the Galactic halo). Based on the expected exposure of the experiments, we estimate the optimal strategy for efficient search of these effects.

Atmospheric ultraviolet and red-infrared flashes from Universitetsky-Tatiana-2 satellite data

Millisecond ultraviolet (240–400 nm) and red-infrared (610–800 nm) flashes were detected in the nighttime atmosphere with the scientific payload installed onboard the Universitetsky-Tatiana-2 micro-satellite. Flashes with various numbers of photons, from 1020 to 1026, were detected within the atmospheric area 300 km in diameter observed by the detector. The flashes differ in duration and temporal profile: from single short flashes ∼1 ms in duration to flashes with a complex profile more than 100 ms in duration. Different global geographic distributions are observed for flashes with different numbers of photons. Flashes with fewer than 1022 photons are distributed uniformly over the Earth’s map. Flashes with more than 1022 photons are concentrated near the equator and above the continents. Series of flashes were observed in one turn of the satellite when flying not only over thunderstorm regions but also over cloudless ones. The flash number distribution has been derived from the ratio of the numbers of red-infrared and ultraviolet photons. As applied to discharges in the upper atmosphere, whose glow is dominated by the emission in the first and second positive systems of molecular nitrogen bands (1PN2 and 2PN2), this distribution is equivalent to the flash altitude distribution in the atmosphere. The observed ratio of the numbers of photons in red-infrared and ultraviolet flashes agrees with the calculated one for electric discharges at altitudes higher than 50 km. In-orbit measurements of the charged particle flux (with a threshold energy for electrons of 1 MeV) provide no evidence for a synchronous occurrence of an ultraviolet flash and a burst in the particle flux in the orbit.

Space Program KOSMOTEPETL (project KLYPVE and TUS) for the study of extremely high energy cosmic rays

The scientific goal of the KOSMOTEPETL program is to observe and to study ultra high energy cosmic rays through the fluorescent tracks that they produce in the Earth atmosphere with the help of satellite based optical cameras based on the technology of a large mirror-concentrator of light. At low orbits (400–600 km) a mirror with an area of 400 m2 will allow us to observe neutrino induced horizontal tracks starting at the energy threshold of 1 EeV. With these neutrinos, which have to be produced in collisions of extreme energy cosmic rays (with energy >50 EeV) with background photons at distances >100 Mpc, the most distant cosmic ray sources will be revealed. Design of the TUS and KLYPVE detectors (the first detectors of the KOSMOTEPETL program with a mirror area 2 and 10 m2) is presented.

The current status of orbital experiments for UHECR studies

Two types of orbital detectors of extreme energy cosmic rays are being developed nowadays: (i) TUS and KLYPVE with reflecting optical systems (mirrors) and (ii) JEM-EUSO with high-transmittance Fresnel lenses. They will cover much larger areas than existing ground-based arrays and almost uniformly monitor the celestial sphere. The TUS detector is the pioneering mission developed in SINP MSU in cooperation with several Russian and foreign institutions. It has relatively small field of view (+/-4.5 deg), which corresponds to a ground area of 6.4x10^3 sq.km. The telescope consists of a Fresnel-type mirror-concentrator (~2 sq.m) and a photo receiver (a matrix of 16x16 photomultiplier tubes). It is to be deployed on the Lomonosov satellite, and is currently at the final stage of preflight tests. Recently, SINP MSU began the KLYPVE project to be installed on board of the Russian segment of the ISS. The optical system of this detector contains a larger primary mirror (10 sq.m), which allows decreasing the energy threshold. The total effective field of view will be at least +/-14 degrees to exceed the annual exposure of the existing ground-based experiments. Several configurations of the detector are being currently considered. Finally, JEM-EUSO is a wide field of view (+/-30 deg) detector. The optics is composed of two curved double-sided Fresnel lenses with 2.65 m external diameter, a precision diffractive middle lens and a pupil. The ultraviolet photons are focused onto the focal surface, which consists of nearly 5000 multi-anode photomultipliers. It is developed by a large international collaboration. All three orbital detectors have multi-purpose character due to continuous monitoring of various atmospheric phenomena. The present status of development of the TUS and KLYPVE missions is reported, and a brief comparison of the projects with JEM-EUSO is given.

A New Type of Space Telescope for Observation of Extreme Lightning Phenomena in the Upper Atmosphere

A new type of space telescope with a 3 mm × 3 mm Micro-Electro-Mechanical System (MEMS) micromirror array has been fabricated and launched into space. This telescope has unique features: a wide field of surveillance view, and fast zoom-in and tracking capabilities. Although the micromirror array area is small, the space telescope was capable of observing the space-time development of extreme lightning in the upper atmosphere. It fulfilled its purpose by proving the principles of a space telescope. The concept and technologies used in this telescope can be extended to large MEMS space telescopes for future missions for earth and space science, including gamma ray bursts and ultra high energy cosmic rays. The performance of the space telescope during the ground test before launch as well as its performance in space are here presented to demonstrate the fast zoom-in and tracking capabilities of the telescope.