Whistler mode propagation in the earth and planetary magnetospheres and ray tracing techniques

Whistler mode wave phenomena observed in the earth's environment and in the planetary magnetospheres, such as in the vicinity of the Jupiter, Venus, and Saturn are reviewed, Importance of ray tracing technique is stated in connection with the interpretation of these phenomena. A historical review of ray tracing technique is then given. Finally the most recent ray tracing technique, such as 3-D ray tracing in a non-dipolar background magnetic field model is introduced.     

SAMBO-GEOS : Electric field measurements in the disturbed ionosphere and magnetosphere

Measurements of the electric field in the ionosphere and the equatorial plane during the pre-onset and actives phases of a substorm (March 4, 1979) are compared. Correlations and disagrements between the measurements are considered. The preliminary conclusion is reached that the model of electrojet polarisation proposed by CORONITI and KENNEL (1972) could possibly explain part of our observations.     

Adaptive Tracker Field-of-View Variation Via Multiple Model Filtering

Adaptive estimation using multiple model filtering is investigated as a means of changing the field of view as well as the bandwidth of an infrared image tracker when target acceleration can vary over a wide range. The multiple models are created by tuning filters for best performance at differing conditions of exhibited target behavior and differing physical size of their respective fields of view. Probabilistically weighted averaging provides the adaptation mechanism. Each filter involves online identification of the target shape function, so that this algorithm can be used against ill-defined and/or multiple-hot-spot targets. When each individual filter has the form of an enhanced correlator/linear Kalman filter, computational loading is very low. In contrast, an extended Kalman filter processing the raw infrared data directly and assuming a nonlinear constant turn-rate dynamics model provides superior tracking capability, especially for harsh maneuvers, at the cost of a larger computational burden.     

A system of autonomous navigation and orientation for satellites based on virtual measurements of zenith distances of stars

An onboard astronomical system is suggested, based on the developed method using virtual measurements of zenith distances of stars. Two algorithms of the method are described, their theory is given, and statistical results of the system’s simulation are presented.     

Numerical solutions to exact equations of motion along near-optimal multi-orbit trajectories for a spacecraft in a Newtonian gravitational field

The actual topic of optimization of multi-orbit low-thrust spacecraft inter-orbital transfers is considered. We have developed an original approach to solving this problem, and it is described.     

Dynamics of Temperature and Density of Cold Protons of the Earth's Plasmasphere Measured by the Auroral Probe/Alpha-3 Experiment Data during Geomagnetic Disturbances

We present the results of temperature and density measurement of plasmaspheric protons under quiet and disturbed conditions in the night and dayside sectors of the plasmasphere obtained with the Auroral Probe/Alpha-3 instrument during September 1996 and January 1997. According to the experimental data, the proton temperature in the night sector of the plasmasphere depends on the level of geomagnetic disturbance: it is found that at night hours the values of temperatures inside the plasmasphere at 2.4 < L < 3.5 decreased considerably after the commencement of a geomagnetic storm. The temperature decrease, as a rule, was accompanied by the formation of a flat plateau on the density distribution n(L) at 2.4 < L < 3.5. The above experimental facts (decreasing proton temperature and formation of a flat part on the n(L) distribution) allow us to conclude that the decrease in the proton temperature in the night sector of the plasmasphere connected with magnetic disturbances is caused by the filling of field tubes (depleted after the commencement of the storm) with colder ionospheric plasma. The proton temperature in the dayside sector of the plasmasphere virtually does not depend on the level of the geomagnetic disturbance.     

Systematic approach to life support system analyses and integration.

This paper is devoted to the consideration of possible viewpoint on CELSS development and design. If the aim to create practically applicable CELSS is accepted then the task to optimize the process of CELSS research and development in terms of minimum cost, hours, maximum applicability, scientific contribution, etc. becomes actual. Requirements of applicability and scientific significance are synergetic since understanding of general properties of CELSS gives an ability to create CELSS for different applications. To accomplish the task three main groups of parameters have to be optimized: i) configuration and operating parameters of developing CELSS itself; ii) organizational management of research and development of CELSS; iii) features of an area where CELSS is planned to be used (space missions, terrestrial applications, or biosphere investigation) and where requirements to CELSS characteristic come from. Given paper is a brief review presented some attempts to arrange mentioned above into some set of formalized and interacting criteria, and some progression of research stages derived from these criteria.     

TV space surveillance system

This article represents the research results of the television space surveillance system, or, in other words, the optical surveillance system. The purpose of the work is the design of a specialized optical surveillance system, stabilization and surveillance equipment, and a television unit. The system's simplified structural and functional scheme is described, as well as its justification and operation principle. The application prospects are estimated.     

Comments on ?M-Ary Cpsk Detection with Noisy Reference and Interiverers?

The effect of cycle slips of the carrier recovery phase-locked loop (PLL) on the performance of coherent M-ary phase-shift keyed (MPSK) systems is dealt with. It is shown that each cycle slip causes a 1 bit error in a differentially encoded and Gray encoded signal stream. Different situations are investigated and compared with regard to the effect of these errors.     

Clinical effects of thigh cuffs during a 7-day 6 degrees head-down bed rest.

Thigh cuffs are used by Russian cosmonauts to limit the fluid shift induced by space flight. A ground simulation using the head-down bed rest (HDBR) model was performed to assess the effects of thigh cuffs on clinical tolerance and orthostatic adaptation. 8 male healthy volunteers (32.4 +/- 1.9 years) participated twice in a 7-day HDBR--one time with thigh cuffs (worn daily from 9 am to 7 pm) (TC) and one time without (WTC). Orthostatic tolerance was assessed by a 10 minute stand test and by a LBNP test (5 min at -15, -30, -45 mmHg) before (BDC-1) and at the end of the HDBR period (R+1). Plasma volume was measured before and at the end of HDBR by the Evans blue dye dilution technique. Thigh cuffs limits headache due to fluid shift, as well as the loss in plasma volume (TC: -5.85 +/- 0.95%; WTC: -9.09 +/- 0.82%, p<0.05). The mean duration of the stand test (R+1) did not differ in the two group (TC 7.1 +/- 1.3 min; WTC 7.0 +/- 1.0 min). The increase in HR and decrease in diastolic blood pressure were slightly but significantly larger without thigh cuffs. Duration of the LBNP tests did not differ with thigh cuffs. Thigh cuffs limit the symptoms due to fluid shift and the loss in plasma volume. They partly reduced the increase in HR during orthostatic stress but had no effect on duration of orthostatic stress tests.