Risk Factors of Negative Impact on Objects of the Environment upon Accidents during Launches of Rocket-Space Hardware

The probabilistic aspects of rocket accidents during their launching and the motion in the troposphere are discussed. Schemes of forming the probability damage fields of risk recipients (the environment objects) are given. As an example of a use of the developments obtained, probability fields of objects" damage from the impact of an air shock wave are calculated.     

Computational analysis of strength,stability, and durability for gas turbine engine exhaust frame

A computational technique, developed for analysis of strength, stability and low-cycle durability of GTE exhaust frame complex structure under operational and emergency loads is described. The presented technique, based on the ANSYS and STAR-CD engineering analysis software, and self-design software can improve the accuracy and efficiency of calculations, and reduce efforts on finite element mesh development, performing calculations and processing of results.     

Cell-to-cell interactions in changed gravity: ground-based and flight experiments

Cell-to-cell interactions play an important role in all physiological processes and are mediated by humoral and mechanical factors. Mechanosensitive cells (e.g., osteocytes, chondrocytes, and fibroblasts) can be studied ex vivo to understand the effects of an altered gravity environment. In particular, cultured endothelial cells (EC) are very sensitive to a broad spectrum of mechanical and biochemical stimuli. Earlier, we demonstrated that clinorotation leads to cytoskeletal remodeling in cultured ECs. Long-term gravity vector changes also modulate the expression of surface adhesion molecules (ICAM-1, E-selectin, VCAM-1) on cultured ECs. To study the interactions of geterological cells, we cocultured endothelial monolayers and human lymphocytes, immune cells and myeloleucemic (K-560) cells. It was found that, although clinorotation did not alter the basal adhesion level of non-activated immune cells on endothelial monolayers, the adhesion of PMA-activated lymphocytes was increased. During flight experiments onboard the Russian segment of the International Space Station, we measured the cytotoxic activity of natural killer (NK) cells incubated with labeled target cells. It was found that immune cells in microgravity retained their ability to contact, recognize, and destroy oncogenic cells in vitro. Together, our data concerning the effects of simulated and real microgravity suggest that, despite changes in the cytoskeleton, cell motility, and expression of adhesion molecules, cell-cell interactions are not compromised, thus preserving the critical physiological functions of immune and endothelial cells.     

Developing a vitamin greenhouse for the life support system of the International Space Station and for future interplanetary missions.

In order to evaluate the effects of gravity on growing plants, we conducted ground based long-term experiments with dwarf wheat, cultivar Apogee and Chinese cabbage, cultivar Khibinskaya. The test crops had been grown in overhead position with HPS lamp below root module so gravity and light intensity gradients had been in opposite direction. Plants of the control crop grew in normal position under the same lamp. Both crops were grown on porous metallic membranes with stable -1 kPa matric potential on their surface. Results from these and other studies allowed us to examine the differences in growth and development of the plants as well as the root systems in relation to the value of the gravity force influence. Dry weight of the roots from test group was decreased in 2.5 times for wheat and in 6 times - at the Chinese cabbage, but shoot dry biomass was practically same for both test and control versions. A harvest index of the test plants increased substantially. The data shows, that development of the plants was essentially changed in microgravity. The experiments in the space greenhouse Svet aboard the Mir space station proved that it is possible to compensate the effects of weightlessness on higher plants by manipulating gradients of environmental parameters (i.e. photon flux, matric potential in the root zone, etc.). However, the average productivity of Svet concerning salad crops even in ground studies did not provide more than 14 g fresh biomass per day. This does not provide a sufficient level of supplemental nutrients to the crew of the ISS. A cylindrical design of a space plant growth chamber (SPGC) allows for maximal productivity in presence of very tight energy and volume limitations onboard the ISS and provides a number of operational advantages. Productivity from this type of SPGF with a 0.5 kW energy utilization when salad growing would provide approximately 100 g of edible biomass per day, which would almost satisfy requirements for a crew of two in vitamin C and carotene and partly vitamin B group as well as rough fiber.     

Measurement of Vibration Microaccelerations onboard the Mir Orbital Station Using the VM-09 System of Accelerometers

The results of processing the data of measurements of microaccelerations, carried out onboard the Mir orbital station using the Russian VM-09 system of accelerometers, are described. The system was developed by the Composite Research-Production Association. The sensitivity of this system was 10^–4 m/s²; its frequency band had limits from a few tenths of a hertz up to 100 Hz. The measurements were carried out in the real-time mode of data transmission to the Earth, when the orbital station flew over the telemetry data receiving point. The instrument's sampling rate was 200 measurements per second, and the length of a continuous run of measurements did not exceed 10 min. The following problems are considered in the paper: (1) isolation of cyclic trends from the measurement data; (2) estimation of spectral density of the data component with a continuous spectrum; and (3) low-frequency filtration of the measurement data     

Results of Space-Flight Tests of the Vibration-Protective Platform VZP-1K

The data of microacceleration measurements performed onboard the Mirstation are analyzed. The data were taken while testing the passive vibration-protective platform VZP-1K developed by the NPO Kompozit. We have processed the results of simultaneous microacceleration measurements on the vibration-protective platform and on the station body close to the platform. Two sets of the French equipment Microaccelerometer were used for these measurements. It was found that the platform reduces the vibrational component of microaccelerations in the band of frequencies above 3 Hz by more than a factor of 10. In this case, all harmonics with large amplitudes are damped by a factor of 50 and more, and some harmonics with small amplitude are damped only by a factor of 10. In the band 0.3–0.6 Hz (close to natural frequencies of the platform), the several-fold increase in amplitude of the vibrational component of microaccelerations is observed, but since the initial values of this amplitude in all performed experiments were small, the above indicated increase practically has not decreased the vibration-protective properties of the platform. The estimations of natural frequencies and damping coefficients of the platform found as a result of data processing of microacceleration measurements made during its free oscillations are obtained. The dependence of frequencies on the amplitude of oscillations is revealed for one mode, which testifies to appreciable nonlinear effects.     

Determination of quasi-static microaccelerations onboard a satellite using video images of moving objects

A space experiment aimed at determination of quasi-static microaccelerations onboard an artificial satellite of the Earth using video images of the objects executing free motion is considered. The experiment was carried out onboard the Foton M-3 satellite. Several pellets moved in a cubic box fixed on the satellite’s mainframe and having two transparent adjacent walls. Their motion was photographed by a digital video camera. The camera was installed facing one of the transparent walls; a mirror was placed at an angle to another transparent wall. Such an optical system allowed us to have in a single frame two images of the pellets from differing viewpoints. The motion of the pellets was photographed on time intervals lasting 96 s. Pauses between these intervals were also equal to 96 s. A special processing of a separate image allowed us to determine coordinates of the pellet centers in the camera’s coordinate system. The sequence of frames belonging to a continuous interval of photography was processed in the following way. The time dependence of each coordinate of every pellet was approximated by a second degree polynomial using the least squares method. The coefficient of squared time is equal to a half of the corresponding microacceleration component. As has been shown by processing made, the described method of determination of quasi-static microaccelerations turned out to be sufficiently sensitive and accurate.     

A Magnetospheric Substorm and the Motion of the Magnetopause

Using a single event as an example, we make an analysis of the time development of a substorm and estimate its influence on the motion of the low-latitude boundary of the magnetosphere. To this end, we compare the data on plasma and magnetic field obtained by five spacecraft (WIND, INTERBALL-1, GEOTAIL, GOES-8, and GOES-9) with measurements made by ground-based stations. It is shown that the release of energy of the geomagnetic tail begins from a disruption of the current sheet near the Earth. The high-speed plasma stream that transfers a magnetic flux to the Earth and can have an effect on the magnetic field configuration near the Earth is detected later. Almost simultaneously with a substorm onset a series of magnetopause crossings has been detected by the INTERBALL-1 satellite on the evening side of the low-latitude magnetosphere. In this paper we consider some of possible causes of this motion of the magnetosphere boundary, including variations of parameters of the solar wind, Kelvin-Helmholtz instability, and substorm processes. It is shown that fast motions of the magnetopause are detected almost simultaneously with field variations in the near magnetotail of the Earth and geomagnetic pulsations Pi2 on ground-based stations. A sufficiently high degree of correlation (K = 0.67) between the amplitude of Pi2 pulsations and the amplitude of magnetic field variations near the magnetopause is probably indicative of the connection of short-term motions of the magnetosphere boundary with the tail current disruption and the process of formation of a substorm current wedge.__________Translated from Kosmicheskie Issledovaniya, Vol. 43, No. 4, 2005, pp. 248–259.Original Russian Text Copyright © 2005 by Nikolaeva, Parkhomov, Borodkova, Klimov, Nozdrachev, Romanov, Yermolaev.