Measurements of Energy of Cosmic-Ray Nuclei by Specific Energy Release at the Hadron Cascade Maximum

A method of measuring the particle energy in the range higher than 1 TeV based on detection of the maximum specific energy release in hadron cascades that develop in dense media is proposed and studied. This method makes it possible to improve the accuracy of energy measurements carried out with partial-absorption ionization calorimeters in the high-altitude studies of energy spectra of high-energy cosmic rays. The attainable accuracies of energy measurements are considered for light, intermediate, and heavy nuclei in iron and lead absorbers. The results of modeling are compared with the data of an experiment onboard the Kosmos-1713 satellite.     

Learning via satellite

This report describes a global applied research project — Project Learn — being sponsored by the International Space University in Strasbourg, which aims to address key educational needs, particularly in remote and rural areas, via satellite. The project aims to bypass conventional approaches to education, health care and communications development by using global information technologies at a local level and drawing a range of international organizations into a cooperative effort. Examples of the kind of work to be undertaken by the project are presented.     

Conception of spacecraft centralized power supply

A reliable power supply for spacecraft is one of the central problems determining the future development of space technology. The traditional solution to this problem implies having an autonomous power plant on board each spacecraft. The most widely used are power plants with solar cells. However, there exists an alternative power supply concept of using a centralized power supply system (CPSS) and power transmission to the user satellites by laser or microwave beams. Use of a CPSS has a number of advantages. In particular, it allows the spacecraft to increase power supply level and service life as well as to decrease the spacecraft mass and cost. However, it sets new physical and technical problems associated with long distance power transmission and requires some changes in spacecraft structure and concepts. The feasibility study of CPSS development and use has to rely on existing or firmly forecastable technologies. An attempt of such an analysis has been done by a group of scientists at Moscow State Aviation Institute during 1994-1996. The very first results have already been published. This paper discusses new results obtained lately regarding a space based CPSS     

The on-board computer in diagnosis of satellite power unit

Diagnosis of a space thermoemission power unit incorporating a Topaz type reactor converter is hindered by the low potential of the measurement system. The lack of information is restored by computing from the measurement date. Examples of dynamic mode diagnosis with restoration of information on the field temperature is given. The power unit diagnosis algorithms are implemented in the onboard computer whose power is about 200,000 operations per second. Memory and computing requirements are determined from algorithms of different diagnosis degrees. Results in study of the necessary computer component redundancy are given for different models of system degradation. The redundancy level should insure that the nucleus of the computer system with a minimally necessary 4K-words memory remains in operation after three years into the mission.     

The structure of the solar corona as observed by the Solar Extreme ultraviolet Rocket Telescope and Spectrograph

Data from the Solar Extreme-ultraviolet Rocket Telescope and Spectrograph (SERTS) have been used to address a number of important scientific problems. The primary strength of the SERTS data is the fact that this spectral range is rich with emission lines. Over 270 lines are seen in the SERTS active Sun spectrum, from 57 different ions. For example, multiple (≥4) lines are observed for all ionization states of iron from Fe IX to Fe XVII. Temperatures and densities have been derived for a number of active and quiet Sun regions, the coronal magnetic field strength has been estimated for both a plage region and an active region.     

Population inversion and gain distribution in supersonic mixed flow systems

Experimental results are reported for small signal gain distribution across a cavity of a mixed flow gasdynamic laser system at different turbulent supersonic mixing regimes. It is shown that the temperature range of the GDL generation regime can be extended up to 7000°K, and gain coefficients as high as 3.5 m⁻¹ be attained in a “double-freeze” supersonic gas flow. Basic advantages are discussed as well as the opportunity to obtain higher efficiencies in thermally pumped laser systems.     

Simulation of space cabin atmosphere

The Soyuz 22 space cabin atmosphere was studied for volatile organic trace contaminants. By gas chromatography the following constituents were identified: methane, ethane, heptane, methanol, ethanol, n-propanol, acetaldehyde, acetone, ethyl benzene. Except for acetone, concentrations of the above compounds were close to the values determined in the mock-up experiments.     

Upgrading conical scan with off-boresight measurements

Adding off-boresight measurements to a conical scan radar can bring the angle accuracy closer to the theoretical attainable limit. A model for off-boresight measurement implementation and its performances are discussed. The expected accuracy is calculated and compared with the Cramer-Rao bound. The model is also used to determine bias error induced by the target dynamics.