Central and regional hemodynamics in prolonged space flights.

This paper presents the results of measuring central and regional (head, forearm, calf) hemodynamics at rest and during provocative tests by the method of tetrapolar rheography in the course of Salyut-6-Soyuz and Salyut-7-Soyuz missions. The measurements were carried out during short-term (19 man-flights of 7 days in duration) and long-term (21 man-flights of 65-237 days in duration) manned missions. At rest, stroke volume (SV) and cardiac output (CO) as well as heart rate (HR) decreased insignificantly (in short-term flights) or remained essentially unchanged (in long-term flights). In prolonged flights CO increased significantly in response to exercise tests due to an increase in HR and the lack of changes in SV. After exercise tests SV and CO decreased as compared to the preflight level. During lower body negative pressure (LBNP) tests HR and CO were slightly higher than preflight. Changes in regional hemodynamics included a distinct decrease of pulse blood filling (PBF) of the calf, a reduction of the tone of large vessels of the calf and small vessels of the forearm. Head examination (in the region of the internal carotid artery) showed a decrease of PBF of the left hemisphere (during flight months 2-8) and a distinct decline of the tone of small vessels, mainly, in the right hemisphere. During LBNP tests the tone of pre- and postcapillary vessels of the brain returned to normal while PBF of the right and left hemisphere vessels declined. It has been shown that regional circulation variations depend on the area examined and are induced by a rearrangement of total hemodynamics of the human body in microgravity. This paper reviews the data concerning changes in central and regional circulation of men in space flights of different duration.     

A new type of magnetic gimballed momentum wheel and its application to attitude control in space

A new type of magnetically suspended gimbal momentum wheel utilizing permanent magnets is described. The bearing was composed of four independent thrust actuators which control the rotor thrust position and gimbal angles cooperatively, so that the bearing comes to have a simple mechanism with high reliability and light weight. The high speed instability problem due to the internal damping was easily overcome by introducing anisotropic radial stiffness. A momentum flywheel with the 3-axis controlled magnetic bearing displays good performance for attitude control of satellite with biased momentum.     

Inertial deposition of suspended particles in a flow around a porous cylinder

The results of studying a dispersed airflow around a single porous cylinder are presented. The flow field of carrying medium outside the cylinder is described within the framework of the Navier-Stokes equations for incompressible gas; inside the porous cylinder the Darcy-Brinkman extended equations for averaged velocity are used. The numerical solution of the medium equations is achieved in the FLUENT package. In the found field of carrying medium velocities the suspended particle trajectories are calculated. Also given are the dependences of the particle inertial deposition effectiveness on the Stokes number at various values of the Darcy number.     

Response of a pentagonal PZT element as a component of a 4π-real-time detector

The detector characteristics of a pentagonal element were studied by colliding it with hypervelocity micro-particles. A charge-sensitive amplifier was developed for the element of its capacitance ∼10 nF. The output amplitudes were expressed as a linear function of the momentum at collision. Empirical formulas obtained from on-ground experiments could be used for the calibration of the detector. The pentagonal element was potential to measure the momentum during collision from the output amplitude. A set of electrodes on the surface was used to confirm the measurement of the coordinates at collision. A possible application of this pentagonal element on a real-time dust detector was discussed.     

The influence of effects of the heliospheric interface on parameters of backscattered solar <Emphasis Type="Italic">L</Emphasis>α radiation measured at the Earth’s orbit

A new kinetic model of distribution of interstellar hydrogen atoms in the heliosphere is suggested in this paper. It takes into account global effects associated with charge exchange of interstellar atoms near the heliospheric boundary. The constructed model allows one to find efficiently the detailed distribution of hydrogen atoms over space and velocities. For the axisymmetric steady-state case a comparison is made of the parameters of interstellar hydrogen atoms that were obtained using the classical hot model, two modifications of the improved hot model, and a global self-consistent kinetic gas-dynamic model of the heliospheric interface. The results of calculations of the spectral moments of scattered solar Lα radiation are presented. They were derived on the basis of different models of distribution of hydrogen atoms in the heliosphere.     

Development Engineering on System 465L

The development engineering involved in large scale systems is but one of many problems included in acquisition of these systems. The purpose of this paper is to explore some of the engineering problems encountered in the development of the Strategic Air Command and Control System 465L and to indicate how the interaction between the technical problems and the nontechnical problems affects the final engineering decisions. In this paper we will indicate the basic requirements for the system and show how the system was configured to meet these requirements. The deficiencies uncovered in the design and first cut solutions to the problems and the compromises which were necessary to implement the system will also be discussed. Illustrative examples will be used to show how the design evolved into the final system configuration which is now in use.     

Regeneration of water at space stations

The history, current status and future prospects of water recovery at space stations are discussed. Due to energy, space and mass limitations physical/chemical processes have been used and will be used in water recovery systems of space stations in the near future. Based on the experience in operation of Russian space stations Salut, Mir and International space station (ISS) the systems for water recovery from humidity condensate and urine are described. A perspective physical/chemical system for water supply will be composed of an integrated system for water recovery from humidity condensate, green house condensate, water from carbon dioxide reduction system and condensate from urine system; a system for water reclamation from urine; hygiene water processing system and a water storage system. Innovative processes and new water recovery systems intended for Lunar and Mars missions have to be tested on the international space station.     

Accomplishment of multi-utility spacecraft charging analysis tool (MUSCAT) and its future evolution

(MUSCAT) is a high value computation tool for analyzing spacecraft–plasma interaction, whose typical example is charging–arcing issue, corresponding to spacecrafts in LEO, GEO and PEO. JAXA and Kyushu Institute of Technology (KIT) started the development as a joint project in November 2004 and the final version of MUSCAT was released in March 2007. The final version includes many important features to simulate spacecraft–plasma interaction and the features can be separated into four parts. The first part is its GUI named “Vineyard”. By using Vineyard, MUSCAT users can build a satellite model including not only its geometry but also material properties of the surface. As for the second part, MUSCAT includes many kinds of effects derived from space plasma environment as well as electrical functions of spacecraft. For the third part, MUSCAT can work on parallel workstation with multi-CPU. The last feature is that the computation result by MUSCAT was thoroughly validated by experiments in plasma chamber. The numerical result shows very good agreement with the code validation experiment. We also conducted trial computation of charging analysis on Greenhouse gases Observing Satellite (GOSAT) with MUSCAT. One purpose of the computation was prediction of charging status of GOSAT for the real satellite design in combination with the ground test. The other is performance assessment of MUSCAT. After the joint project, expansion and maintenance of MUSCAT will be carried out by “MUSCAT Space Engineering Ltd” which is a new enterprise made of the development team. In future we will try to conduct MUSCAT computation for various spacecrafts and also try to add useful function such as 3D CAD compatibility.     

CAVORT: A Radar Pulse Train Optimum Processor for Accelerating Targets

The CAVORT analog radar signal processor for matched filtering of coherent pulse trains from targets displaying significant radial acceleration is described. CAVORT employs a scanning technique to search repeatedly through trial pairs of values for Doppler and Doppler rate. When a target appears, it is detected, and the best-fitting pair of values determined. The principle of operation is illustrated, using photographs of waveforms generated by the equipment. The resuilts of satellite observations are included. It is demonstrated that the experimental CAVORT which integrates half-second segments of signal gives satisfactory estimates of acceleration.