Instantaneous triple-probe method for the direct display of plasma parameters in a spacecraft condition

It is proposed that the instantaneous triple-probe method can be applied to the direct display of parameters; particularly in the case of probe application during measurements carried out from spacecraft. The theory of the triple-probe method has been extended for the very high speed flowing collisionless plasma condition, i.e. in which the spacecraft speed U ≈ the most probable electron thermal velocity v_e > the most probable ion thermal velocity v_i. This condition is particularly important both in the case of re-entry of spacecraft and in the solar wind plasma. Experiments have been conducted in a free molecular beam plasma chamber for S_i = U/v_i > 10. The experimental results and their relationship to the appropriate theory are presented.     

Determination of spacecraft and phobos parameters of motion in the Phobos-Grunt project

For the needs of the upcoming flight to Phobos within the framework of the project Phobos-Grunt, a dynamical numerical theory of the motion of Phobos is developed on the basis of Earth-based and spacecraft (SC) optical measurements and Earth-based radio observations of the SC motion. The theory uses the most reliable astronomical constants. Within the framework of a unified dynamical model, an algorithm is proposed for the joint correction of Phobos and the spacecraft parameters of motion, among which are the secular acceleration of Phobos and its gravitational constant. The accuracy of the obtained ephemeris is estimated for the time of the SC arrival to Phobos.     

Microstrip antenna array for the onboard radio system of small spacecraft

The article presents the results of the development of a directional microstrip antenna array with small mass-dimensional characteristics as a directional antenna of the transmitting channel of a small spacecraft.     

Applying the circuit theory to the development of an algorithm for designing the pneumohydraulic system of a spacecraft powertrain

This article considers the application of circuit theory methods for developing a mathematical model of the branched pneumohydraulic system (PHS) of a spacecraft powertrain (PT). The parts of the PHS are treated as elements with lumped constants. The design principles are defined. The methodology for developing a mathematical model for the PHS is described.     

A basic system of equations in the field of a rotationally symmetric potential

We consider system of equations of motion in the field of a rotationally symmetric potential.     

Use of a discrimination rule for predicting a successful spacecraft landing on the surface of a celestial body

An estimate for the probability of a successful spacecraft landing în the complex relief of a celestial body given random initial landing conditions is considered. The estimation is performed according to values of these initial conditions, including landing orientation, the linear and angular velocity of the lander, as well as surface relief and behavior of the ground at the landing site. For a trial sample involving random landing situations, the equations of motion of the lander are solved, from which the discrimination rule is derived. Then a successful landing is predicted by means of the rule without the solution of the equations of motion during landing.     

The development of the scientific and design school of G.N. Babakin during the creation of deep-space automated spacecraft

This article presents the main outline of the creation of the scientific and design school of G.N. Babakin, who was a corresponding member of the Academy of Sciences of the USSR, during the creation of automated spacecraft for fundamental space research.     

Orbital parameters and variability of the emission spectrum for the massive binary system 103 Tau

Based on high-resolution spectra taken near the He I 6678 Å line for the massive binary system 103 Tau, we have detected a weak absorption component belonging to the binary’s secondary component. We have measured the radial velocities of both components, improved the previously known orbital parameters, and determined the new ones. The binary has an orbital period P _orb = 58.305^d, an orbital eccentricity e = 0.277, a radial velocity semi-amplitude of the bright component K _A = 44.8 km s^?1, and a component mass ratio M _A /M _B = 1.77. The absence of photometric variability and the estimates of physical parameters for the primary component suggest that the binary most likely has a considerable inclination of the orbital plane to the observer, i ≈ 50°?60°. In this case, the secondary component is probably a normal dwarf of spectral type B5–B8. Based on the spectra taken near the H _α line, we have studied the variability of the emission profile. It is shown to be formed in the Roche lobe of the secondary component, but no traces of active mass exchange in the binary have been detected.     

In situ acceleration and gradients of charged particles in the outer solar system observed by the voyager spacecraft

The probable connection between cosmic rays and the electromagnetic state of the interplanetary medium was recognized by Hannes Alfvén as early as 1949 (Alfvén, 1949, 1950); he pointed out that the properties of cosmic rays necessitate a mechanism, external to Earth but within the solar system, capable of accelerating particles to extremely high energies. In advocating the view of local origin for part of the cosmic-ray spectrum, Alfvén and his colleagues developed a very general type of acceleration mechanism called magnetic pumping. The unique data set of the two Voyagers extends over an entire decade (1977–1987) and is most suitable to explore the problem of acceleration of charged particles in the heliosphere. The energy coverage of the Low Energy Charged Particle (LECP) experiment covers the range 30 keV to several hundred MeV for ions and 22 keV to several MeV for electrons. Selected observations of interplanetary acceleration events from 1 to 25 AU are presented and reviewed. These show frequent acceleration of ions to several tens of MeV in association with shocks; highest energies (220 MeV oxygen) were measured in the near-perpendicular ( _Bn 87.5°) shock of January 5, 1978 at 1.9 AU, where electron acceleration was also observed. Examples of ion acceleration in association with corotating interaction regions are presented and discussed. It is shown that shock structures have profound effects on high-energy (70 MeV) cosmic rays, especially during solar minimum, when a negative latitudinal gradient was observed after early 1985 at all energies from 70 MeV down to 30 keV. By early 1987, most shock acceleration activity in the outer heliosphere (25 to 30 AU) had ceased both in the ecliptic (Voyager-2) and at higher (30°) ecliptic latitudes (Voyager-1). The totality of observations demonstrate that local acceleration to a few hundred MeV, and as high as a few GeV is continually present throughout the heliosphere. It should be noted that in 1954 when Alfvén suggested local acceleration and containment of cosmic rays within the solar system, no one treated his suggestion seriously, at any energy. The observations reviewed in this paper illustrate once more Alfvén's remarkable prescience and demonstrate how unwise it is to dismiss his ideas.Paper dedicated to Professor Hannes Alfvén on the occasion of his 80th birthday, 30 May 1988.     

Physical and geometrical parameters of the binary system gliese 150.2

The speckle interferometric binary system Gl 150.2 (HIP17491) is analyzed using atmosphere modeling and dynamical analysis simultaneously. A synthetic spectral energy distribution (SED) for each of the two components of the system is built using Kurucz blanketed models. These SEDs are combined together to form the total flux, which is compared with the observed one in an iterative method to get the best fit. The parameters of the individual components which lead to the best fit are: T _eff ^A = 5350 ± 50 K, T _eff ^B = 4400 ± 50 K, log g ^A = 4.40 ± 0.05, log g ^B = 4.68 ± 0.05, R ^A = 0.95 ± 0.06R _⊙, R ^B = 0.58 ± 0.06R _⊙, and π = 38.63 ± 0.79 mas, as given by the modified Hipparcos measurement. A modified orbit of the system is introduced and compared with earlier orbits. Hence, the masses of the two components are derived from the coincidence between the atmosphere modeling and dynamical analysis. Based on the estimated physical and geometrical parameters of the system, which are confirmed by synthetic photometry, the spectral types and luminosity classes of the two components are found to be G9.5V and K7V for the primary and secondary stars respectively, with an age of about 8 Gyr. Finally, the positions of both components on the H-R diagram are plotted, and the formation and evolution of the system are discussed.     

Proposals for the construction of space systems based on small spacecraft and a transport and power module with a nuclear power plant

The concept of interconnected satellite systems for various scientific and engineering applications based on small spacecraft and a transport and power module with a nuclear power plant is discussed. The system is connected by laser radiation from the transport and power module that supplies power to small satellites, establishes high-speed data transmission, and is used to perform high-precision measurements of intersatellite distances. Several practical use cases for such a connected system are considered.     

Simultaneous observations of the near-earth and distant geomagnetic tail during a substorm by ISEE-1, ISEE-3 and geostationary spacecraft

The structure of the geomagnetic tail during a substorm is investigated by combining plasma, magnetic field and energetic particle data from the ISEE-3 spacecraft in the deep tail with similar near-Earth observations from ISEE-1 and geostationary spacecraft. The observations can be interpreted in terms of the neutral-line model of substorms and indicate the formation of a closed-loop field region (“plasmoid”) following substonn onset, which is ejected down the tail. The plasmoid is observed to have a double-loop field structure. This may be the result of a second substonn onset occurring ≈ 25 min after the first, producing a further near-Earth neutral line and closed field loop. During the substorm recovery phase, the substonn neutral line moves tailward to beyond 130 R_E from Earth by some 3 h after substorm onset.     

Application of the method for optimum filtering of measurements for determination and prediction of spacecraft orbits

The article covers the outcome of the method for optimal filtering of measurements developed by the author and aimed at the determination of the time and place of reentry of the Phobos-Grunt spacecraft. So-called two-line elements (TLE) of the orbit of the American Space Surveillance System are used as measurements.     

Optimization of the transfer trajectory of a low-thrust spacecraft for research of Jupiter using an Earth gravity-assist maneuver

The paper analyzes the possibility of the use of a gravity-assist maneuver for flight to Jupiter. The advantage of the Earth gravity-assist maneuver in comparison with the direct transfer in terms of reduction of amount of energy required per transfer is considered. Quantitative and qualitative evaluations of two transfer profiles are given.     

The Zamama-Thor region of Io: Insights from a synthesis of mapping, topography, and Galileo spacecraft data

We have studied data from the Galileo spacecraft's three remote sensing instruments (Solid-State Imager (SSI), Near-Infrared Mapping Spectrometer (NIMS), and Photopolarimeter-Radiometer (PPR)) covering the Zamama-Thor region of Io's antijovian hemisphere, and produced a geomorphological map of this region. This is the third of three regional maps we are producing from the Galileo spacecraft data. Our goal is to assess the variety of volcanic and tectonic materials and their interrelationships on Io using planetary mapping techniques, supplemented with all available Galileo remote sensing data. Based on the Galileo data analysis and our mapping, we have determined that the most recent geologic activity in the Zamama-Thor region has been dominated by two sites of large-scale volcanic surface changes. The Zamama Eruptive Center is a site of both explosive and effusive eruptions, which emanate from two relatively steep edifices (Zamama Tholi A and B) that appear to be built by both silicate and sulfur volcanism. A ∼100-km long flow field formed sometime after the 1979 Voyager flybys, which appears to be a site of promethean-style compound flows, flow-front SO₂ plumes, and adjacent sulfur flows. Larger, possibly stealthy, plumes have on at least one occasion during the Galileo mission tapped a source that probably includes S and/or Cl to produce a red pyroclastic deposit from the same vent from which silicate lavas were erupted. The Thor Eruptive Center, which may have been active prior to Voyager, became active again during the Galileo mission between May and August 2001. A pillanian-style eruption at Thor included the tallest plume observed to date on Io (at least 500 km high) and new dark lava flows. The plume produced a central dark pyroclastic deposit (probably silicate-rich) and an outlying white diffuse ring that is SO₂-rich. Mapping shows that several of the new dark lava flows around the plume vent have reoccupied sites of earlier flows. Unlike most of the other pillanian eruptions observed during the Galileo mission, the 2001 Thor eruption did not produce a large red ring deposit, indicating a relative lack of S and/or Cl gases interacting with the magma during that eruption. Between these two eruptive centers are two paterae, Thomagata and Reshef. Thomagata Patera is located on a large shield-like mesa and shows no signs of activity. In contrast, Reshef Patera is located on a large, irregular mesa that is apparently undergoing degradation through erosion (perhaps from SO₂-sapping or chemical decomposition of sulfur-rich material) from multiple secondary volcanic centers.     

时间、距离、速度、红移基本物理概念的演变简史

为了尝试回答“我们能否观测到退行速度超过光速的星系”这一问题,重新考察了在牛顿物理学、狭义相对论、广义相对论和宇宙学中的时伺、距离、速度和红移等概念．揭开了一些错误观念的实质,发现只要摆脱狭义相对论先入为主的束缚,上述问题即可迎刃而解．强调了宇宙学并不是纯粹的广义相对论,而是该理论在服从宇宙学原理的条件下的一个特例,其中一系列基本物理概念都因此得到新的内涵。     

Periodic attitudes and bifurcations of a rigid spacecraft in the second degree and order gravity field of a uniformly rotating asteroid

In this work, periodic attitudes and bifurcations of periodic families are investigated for a rigid spacecraft moving on a stationary orbit around a uniformly rotating asteroid. Under the second degree and order gravity field of an asteroid, the dynamical model of attitude motion is formulated by truncating the integrals of inertia of the spacecraft at the second order. In this dynamical system, the equilibrium attitude has zero Euler angles. The linearised equations of attitude motion are utilised to study the stability of equilibrium attitude. It is found that there are three fundamental types of periodic attitude motions around a stable equilibrium attitude point. We explicitly present the linear solutions around a stable equilibrium attitude, which can be used to provide the initial guesses for computing the true periodic attitudes in the complete model. By means of a numerical approach, three fundamental families of periodic attitudes are studied, and their characteristic curves, distribution of eigenvalues, stability curves and stability distributions are determined. Interestingly, along the characteristic curves of the fundamental families, some critical points are found to exist, and these points correspond to tangent and period-doubling bifurcations. By means of a numerical approach, the bifurcated families of periodic attitudes are identified. The natural and bifurcated families constitute networks of periodic attitude families.