Observations of the Subauroral Nonthermal Radio Emission of the Earth in 1995–1998

Results of almost four years of continuous observations of the subauroral nonthermal radio emission (SANE) onboard the Interball-1 satellite are presented. The main features of SANE are described and discussed: the intensity and character of a signal, its appearance in time, beam directivity, propagation distance, and other observed parameters.     

Dynamics of the 0.3–100 MeV Proton Energy Spectra in the Inner Heliosphere in Quiet Periods of 1974–1991

Variations of the proton spectra in the 0.3–100 MeV energy range based on the data of various instruments installed onboard the IMP-8 satellite are studied for very quiet, quiet, and quasi-stable solar activity periods during the years 1974–1991. As many as 118 spectra were approximated by two power laws: the left-hand and galactic branches of the spectrum were fitted by the AE ^– function and a dependence of the CE type, respectively, the sum J(E) = AE ^– + CE providing the total spectrum. It is shown that the spectra vary within a solar cycle with a shift of the minimum energy (E _min) to higher energies with increasing solar activity. It follows from the relations between the spectrum parameters thus obtained that, in particular periods of time, an increase (decrease) of the particle flux in the low-energy branch of the spectrum and an intensification (depression) of the GCR particle flux modulation take place simultaneously. This is manifested in a shift of the spectrum parallel to the energy axis. The study of the spectra in the most quiet time during three successive solar minima have shown that low-energy (0.3–10 MeV) protons, as well as GCR, are subject to the 22-year variation in the solar magnetic cycle.     

Influence of simulated high-G on the weld size of aL–lI alloy

Whether welding processes are used on earth or in space, they have the same objective: to obtain defect-free welds. To fully understand the effect of gravity on the weld pool geometry and solidification one should perform experiments within a broad range of gravitational acceleration. High-gravity arc welding experiments were done on Al–Li alloy using the centrifuge called Multi-Gravity Research Welding System (MGRWS). At a high “g” level, buoyancy-driven flow is the dominant force in the weld pool over the Marangoni and the electromagnetic forces. Preliminary results show that the average grain size in the fusion zone at 1g is smaller that at 5g.     

Variations in the Parameters of Radio Waves in the Earth’s High-Latitude Ionosphere on the Satellite–Satellite Paths during the Geomagnetic Storm of June 22–23, 2015

Cosmic Research - This paper analyzes the results of about 100 radio occultation sessions of sounding of the high-latitude (>65 °N) lower ionosphere of the Earth’s Northern...     

Variations of the magnetopause position versus the level of geomagnetic activity (according to data of the INTERBALL-1 Satellite for 1995–1997)

The variations in the deviation of the observed position of the magnetosphere boundary from its mean position predicted by the Shue at al., 1997 (Sh97) model [7] are studied as a function of the substorm activity level (the AE-index value) and magnetic storm intensity (the value of the corrected D _st ^* index). The results obtained make it possible to state that the amplitude of motion of the magnetospheric boundary on the dayside and in the low-latitude tail is small. It is likely that the position of the boundary is either independent of the AE and D _st ^* indices or this dependence is weak. At the same time, the boundary of the high-latitude tail shifts inward on the average by 1.5R _E with an increase of the AE-index in the case of absence of magnetic storms (contraction of the magnetospheric tail). On the contrary, in the presence of magnetic storms, this boundary shifts outward by up to 3R _E with an increase of the AE-index (inflation of the magnetospheric tail). It is also shown that the boundary of the high-latitude tail moves outward with an increase of the D _st ^* index, both at low substorm activity and in periods of high substorm activity. The amplitude of the outward motion of the high-latitude tail of the magnetosphere is by a factor of two higher for moderate magnetic storms with strong substorms than for moderate magnetic storms with weak substorms.     

Signs of hypothetical flora on the planet venus: Revision of the TV experiment data (1975–1982)

Unique archive data from investigations of the surface of Venus performed with television cameras on the VENERA missions in 1975 and 1982 were reprocessed with up-to-date techniques, which substantially improved their level of detail. Numerous objects exhibiting a complex regular structure and presumably very slow motions (in the case of hypothetical fauna) have been found. The objects are noticeable in size and may testify to the existence of life. This paper reviews the results of searching for and identifying hypothetical objects of Venusian flora. The detected and identified hypothetical objects considerably exhaust the corresponding potential of the television images. It is concluded that, to investigate the surface of Venus, a new special mission, much more sophisticated than the VENERA missions (1975–1982), should be urgently carried out.     

Proton precipitation to the equator of the isotropic boundary during the geomagnetic storm on November 20–29, 2003

Using NOAA satellite data, we consider the peculiarities of precipitation dynamics for energetic protons to the equator of the isotropy boundary during a geomagnetic storm. In addition to two well-known types of proton precipitation events, a new third type of precipitation is distinguished, which is observed on the dayside at relatively high latitudes. The assumption is made that the third-type precipitation in the dayside sector is associated with the development of ion-cyclotron instability. Apparently, the transverse anisotropy of energetic protons, which is necessary for the development of instability, is caused by splitting of drift shells. All three types of precipitation have different generation regions and different time dynamics during storms. The maximum precipitation intensity takes place in the evening sector during the main phase of a storm. At the storm’s recovery phase major losses of protons of the ring current are due to precipitation in the day and morning sectors.     

Radial gradient of low-energy (∼0.5–2 MeV) protons at 20–80 AU in the solar activity minima of the 22nd and 23rd cycles

The value of the radial gradient of low-energy (0.5–2 MeV) protons in the heliosphere at distances of 20–80 AU in the periods of solar activity minima in 1985–1987 and 1994–1997 was estimated using the data of the Voyager-1 and Voyager-2 spacecraft (s/c). Preliminary results on the dependence of the radial gradient on the distance were obtained for protons of these energies. The value of the radial gradient varies from –3% (AU)^–1 to –1% (AU)^–1 at distances from the Sun of 20–60 AU, reaching +0.7% (AU)^–1 at maximum considered distances (80 AU). The sign reversal of the proton radial gradient at a distance of 60–70 AU is interpreted as the appearance of a new component: up to the point of inversion there are mainly particles of the solar origin and/or accelerated in the inner heliosphere, while after the reversal of the gradients sign the fluxes of particles prevail whose source is located far from the Sun (maybe in the vicinity of the heliosphere boundary in the region of existence of the termination shock).Translated from Kosmicheskie Issledovaniya, Vol. 43, No. 1, 2005, pp. 3–8.Original Russian Text Copyright © 2005 by Logachev, Zeldovich, Surova.     

Broad-search algorithms for the spacecraft trajectory design of Callisto–Ganymede–Io triple flyby sequences from 2024 to 2040, Part I: Heuristic pruning of the search space

Triple flybys of the Galilean moons of Jupiter can capture a spacecraft into orbit about Jupiter or quickly adjust the Jupiter-centered orbit of an already captured spacecraft. Because Callisto does not participate in the Laplace resonance among Ganymede, Europa, and Io, triple flyby sequences involving gravity-assists of Callisto, Ganymede, and Io occur only aperiodically for limited time windows. An exhaustive search of triple-flyby trajectories over a 16-year period from 2024 to 2040 using “blind” searching would require 8,415,358 Lambert function calls to find only 127,289 possible triple flyby trajectories. Because most of these Lambert function calls would not converge to feasible solutions, it is much more efficient to prune the solution space using a heuristic algorithm and then direct a much smaller number of Lambert function calls to find feasible triple flyby solutions. The novel “Phase Angle Pruning Heuristic” is derived and used to reduce the search space by 99%.     

Dynamics of the Radiation Environment in the Near-Earth Space in September–November 2020 according to the Meteor-M and Electro-L Satellite Data

Cosmic Research - The results of a comparative analysis from Russian satellite data on the radiation environment in the near-Earth space during September–November 2020 are presented. The...     

Design of transfer trajectories between resonant orbits in the Earth–Moon restricted problem

The application of dynamical systems techniques to mission design has demonstrated that employing invariant manifolds and resonant flybys enables previously unknown trajectory options and potentially reduces the ΔV$\mathrm{\Delta }V$ requirements. In this investigation, planar and three-dimensional resonant orbits are analyzed and cataloged in the Earth–Moon system and the associated invariant manifold structures are computed and visualized with the aid of higher-dimensional Poincaré maps. The relationship between the manifold trajectories associated with multiple resonant orbits is explored through the maps with the objective of constructing resonant transfer arcs. As a result, planar and three-dimensional homoclinic- and heteroclinic-type trajectories between unstable periodic resonant orbits are identified in the Earth–Moon system. To further illustrate the applicability of 2D and 3D resonant orbits in preliminary trajectory design, planar transfers to the vicinity of L₅ and an out-of-plane transfer to a 3D periodic orbit, one that tours the entire Earth–Moon system, are constructed. The design process exploits the invariant manifolds associated with orbits in resonance with the Moon as transfer mechanisms.     

The Achievements and the Future of the Development of China's Space Technology

China's space cause is based on the development of missile technology. In the 1950s, new China, which was just founded, decided to keep pace with the jet technology times, to begin developing missile and rocket science and technology, and to establish China's new space scientific and technological industry.     

Transforming solar system exploration: The origins of the Discovery Program, 1989–1993

The Discovery Program is a rarity in the history of NASA solar system exploration: a reform program that has survived and continued to be influential. This article examines its emergence between 1989 and 1993, largely as the result of the intervention of two people: Stamatios “Tom” Krimigis of the Johns Hopkins University Applied Physics Laboratory (APL), and Wesley Huntress of NASA, who was Division Director of Solar System Exploration 1990–92 and the Associate Administrator for Space Science 1992–98. Krimigis drew on his leadership experience in the space physics community and his knowledge of its Explorer program to propose that it was possible to create new missions to the inner solar system for a fraction of the existing costs. He continued to push that idea for the next two years, but it took the influence of Huntress at NASA Headquarters to push it on to the agenda. Huntress explicitly decided to use APL to force change on the Jet Propulsion Laboratory and the planetary science community. He succeeded in moving the JPL Mars Pathfinder and APL Near Earth Asteroid Rendezvous (NEAR) mission proposals forward as the opening missions for Discovery. But it took Krimigis's political skill and access to Sen. Barbara Mikulski in 1993 to get the NEAR into the NASA budget, thereby likely ensuring that Discovery would not become another one-mission program.     

Frequency fluctuations of coherent signals from spacecraft observed during dual-frequency radio sounding of the circumsolar plasma in 2004–2008

We have performed spectral processing of the data of experiments on radio sounding of circumsolar plasma by coherent S- and X-band signals from the spacecraft Ulysses, Mars Express, Rosetta, and Venus Express carried out from 1991 to 2009. The experiments were realized in the mode of coherent response, when a signal stabilized by the hydrogen standard is transmitted from the ground station to a spacecraft, received by the onboard systems, and retransmitted to the Earth with conserved coherence. Thus, the signal sounding the coronal plasma passes twice through the medium: on the propagation path ground station — spacecraft and on the same path in the opposite direction. The spectra of frequency fluctuations in both the bands are obtained and, using them, the radial dependences of fluctuation intensities are found, which can be approximated by a power law. It is shown that the ratio of intensities of frequency fluctuations in the S- and X-bands is comparable with the theoretical value and characterizes the degree of correlation of irregularities of the electron density along the propagation path ground station — spacecraft and back. Analysis of the correlation of frequency fluctuations on the two paths allows one to get a lower estimate of the outer scale of the circumsolar plasma turbulence. For heliocentric distances R = 10 solar radii (R _S ) the outer scale is larger than 0.25R _S .     

INTERBALL-1 Observations of the Kilometric “Continuum” of the Earth's Magnetosphere

The electromagnetic radio-frequency emission of the inner region of the Earth's plasmasphere discovered recently by the GEOTAIL satellite [4] and referred to as the kilometric continuum was observed by the INTERBALL-1 satellite (1995–2000) in the 100–500 kHz band in the AKR-X experiment. During a period of low solar activity (1995–1997), this continuum was found leaving the inner plasmasphere at geocentric distances of 2–4R _E as isolated pencil-like (1°–6°) beams located in the magnetic equator plane. During a time of high solar activity (1999–2000), the occurrence of the emission was extremely rare (it was observed only at a considerable fall of this activity). If detected, at the same geocentric distances (2–4R _E) the continuum demonstrated a strongly variable and perturbed character, as well as a considerably larger extension of the beam over the geomagnetic latitude (10°–20° and more). In addition, quasi-periodic (QP) signals, similar to the observed QP emissions of Jupiter, were sometimes detected in this period. The probable nature of the observed features of the kilometric continuum is briefly discussed.     

The Swedish Interplanetary Society (1950–1969) and the formation of IAF and IAA

With a growing interest for rocket technology and space travel after WW II a number of new “space societies” were formed in the period 1948–1951 in addition to the ones already existing in Germany, the UK and the US since before WW II. Soon came the need for a common international platform for exchange of information and experience, and the concept of an international federation of astronautical societies emerged.Sweden was one of the 8 countries to sign the original declaration to create an International Astronautical Federation on October 2, 1950 in Paris at the 1st International Astronautical Congress. The Swedish Society for Space Research (Svenska Sällskapet för Rymdforskning) was formed a few days after the historical event in Paris. The name was soon to be changed to the Swedish Interplanetary Society (Svenska Interplanetariska Sällskapet, SIS). Sweden was one of the 10 countries to sign the IAF foundation in 1951 in London and in the following year the first Constitution of IAF in Stuttgart.The SIS quickly grow to a membership of several hundred persons and its membership in IAF promoted an intensive exchange of journals, and the annual participation at the IAC gave growth to start study projects on spacecraft and sounding rockets, and the publication of astronautical journals in Swedish. In 1957 the first Swede was elected vice-president of IAF.Not too long after the IAF foundation the idea of an international body of distinguished individuals emerged, in addition to the body of "member societies" (IAF). Upon the initiative of Theodor von Karman, Eugen Sänger and Andrew Haley the IAF council approval of an International Academy of Astronautical was given on August 15, 1960 during the 11th IAC in Stockholm. This IAC in Stockholm gave a large publicity to space research and astronautics in Sweden, and put the activities of the SIS in the focus of the general public.This paper presents the Swedish involvement in the foundation of IAF and IAA. It also gives an overview on the positive influence of these two organisations on the work and progress of the Swedish Interplanetary Society and the diffusion of astronautics to the general public in Sweden.     

Time Variations of Low-Energy Protons and Helium Nuclei (0.3–10 MeV/nucleon) during the Quiescent Time of Solar Activity in the Inner Heliosphere

Time variations with a duration of 0.6–1.5 years are studied in the interplanetary space for protons and helium nuclei with energies of 0.3–10 MeV per nucleon at a quiescent time of solar activity. It is shown that at 1 AU in the periods 1978–1981 and 1988–1990, at the phases of growth of the 21st and 22nd solar cycles, the background fluxes of these particles determined as minimum intensity levels in every month increased demonstrating steplike variations. At the same time, the intensity of galactic cosmic rays (GCRs) decreased also with the formation of modulation steps. Each step of low-energy particles was finished by a deep minimum of intensity (gap) in both protons and helium nuclei and with a simultaneous short-term increase of the GCR intensity. We present the results of studying five such steps in the intensity of low-energy particles that were observed simultaneously and were opposite in phase with modulation steps of galactic particles. The lowest values of the H/He ratio were recorded at the end of every step, at the lowest intensities of these particles, i.e., in the gap. The true background population at 1 AU was detected precisely at these time intervals, when the contributions of flare particles and those accelerated in the international space were minimum. Various possibilities of the origination of the steplike variations of the background fluxes of protons and helium nuclei with energies of 0.3–10 MeV per nucleon, correlated with similar GCR variations, are discussed.     

Stochastic models of the earth’s rotation taking the effects of the moon and planets into account

A generalization of kinetic and spectral and correlation equations of fluctuations in the Earths rotation is made taking into account the effect of the Moon and planets (these equations form the basis for corresponding stochastic models). Special attention is paid to a parameterized version of kinetic equations based on the method of normal approximation. The application of linear stochastic models for obtaining the spectral and correlation characteristics of the Earths rotation is considered, including the case of random parameters of the tensor of inertia of a deformable Earth. The results can be used for constructing stochastic models of the Earths rotation over time intervals of 6–10 years.Translated from Kosmicheskie Issledovaniya, Vol. 43, No. 1, 2005, pp. 54–66.Original Russian Text Copyright © 2005 by Markov, Dasaev, Perepelkin, I. N. Sinitsyn, V. I. Sinitsyn.