MATHEMATICAL MODELING: . ... This model is developed on the base of the probabilistic description of the collisional aeronomical processes and is realized on a computer as the numerical system (stochastic model). ... Shematovich, V.I., Bisikalo , D.V.             Nonequilibrium processes in the planetary and cometary atmospheres. ... In Russian) . ... Piarnpuu , A. A.; and Shematovich, V. I.       Construction of structural stochastic models of collision processes in rarefied gas media (abstract) . ...

The ion rocket is another means of providing thrust, more gradually but also more efficiently than a conventional rocket. ... As in the nuclear rocket, the energy which propels the xenon jet comes from a different source; here it is electrical energy from solar cells. The reason an ion rocket is much more efficient than ordinary rockets is the way its jet is produced. ... As with solar sails, solar ion engines are mainly practical in the inner solar system, where ample sunlight is available. ...

Astronomy Picture of the Day . ... 27.09.1998 . ... Einstein 's many visionary scientific contributions include the equivalence of mass and energy (E=mc^2), how the maximum speed limit of light affects measurements of time and space ( special relativity ), and a more accurate theory of gravity based on simple geometric concepts ( general relativity ). ... NASA Web Site Statements, Warnings, and Disclaimers . ... Publications with keywords: time - space . Publications with words: time - space . ...

... Aurora from Space . ... Magnetic Storms . ... The "ring of fire" seen by satellite cameras around the polar caps (picture below) is probably created by electrons leaking from the tail's plasma sheet, whose magnetic field lines form a somewhat imperfect trap. ... One possible explanation involves the close association between auroral arcs and electric currents which flow along field lines between the ionosphere and distant space ( Birkeland currents ). ... Why no aurora at the magnetic poles? ...

Next: Mission Element Points-of-Contact . Previous: Mission Operations Data Transfer . ... Each mission element should ensure that their contact information remains current and notify the RSOG of any changes. ... Non-RSOG mission elements will also use the "dit" list to notify the RSOG (and all other mission elements) of unexpected events that may impact operations elsewhere, e.g., if a tracking station discovers that the spacecraft is in an unexpected configuration. ...

... Equations are obtained for the plane relative motion of the system on the taut thread (on the assumption that the centre of mass of the system moves along the Keplerian elliptic orbit). ... The torques of gravitational forces, aerodynamic pressure, aerodynamic friction and the aerogradient effect are taken into account. ... First, the problem is investigated in case of taut thread and Keplerian elliptic motion of the centre of mass. ... In a general case the free motion is bound to become connected....

... Research objects and scientific purposes . Space scientific program includes development and launch of two supersmall spacecrafts "Universitetskiy" and "Kompas-2" intended for monitoring of radiation conditions near the Earth. ... All the studies conducted in the near-Earth space are characterised by strong radiation fields. ... The circular polar orbits, which cover all the near-Earth space, are the most favorable for comprehensive studies of the radiation conditions near the Earth. ...

... The code delay gives the correct delay for the satellite signal. ... TELESCOPE A IF Output GLONASS Phase Tracking Oscillator TELESCOPE B IF Output GLONASS Phase Tracking Oscillator DELAY TRACK OUTPUT A CORRELATE DELAY TRACK OUTPUT B + - RAW Signal modelling GaCA Random Noise ma CORRELATE CORRECTED + + + Signal modelling GbCA Random Noise mb + Figure 1: Diagram showing principles used in cancelling GLONASS interference from the cross correlation of two antennas. ...

Next: Polarization efficiency: size/shape/orientation effects Up: Optical properties of cosmic Previous: The 2175? feature . To model the interstellar polarization one needs to calculate the forward-transmitted radiation for an ensemble of non-spherical aligned dust grains. ... Let non-polarized stellar radiation passes through a dusty cloud with a homogeneous magnetic field. ... The angle between the line of sight and the magnetic field is ( ). ... where the angle is connected with and ( ). ...

The Arcetri Spectral Code (Landi and Landini 1998) allows to evaluate the spectrum of continuum and line radiation emitted by hot and optically thin plasmas in the spectral range 1-2000 Angstrom. The Code is composed by a large database of atomic data and transition probabilities for calculating spectral line emissivities and a suite of fortran programs able to evaluate free-free, free-bound and two-photon continuum radiation. ... To get he Arcetri Spectral Code related publications . ...

... Planets . ... An artistтАЩs impression of Ceres located in the asteroid belt, with plumes of water vapour rising from its surface. Could Ceres have more water than on Earth? (image credit: ESA/ATG medialab) . ... Ceres, captured by the Dawn Space craft in December 2014, Dawn was 740,000 miles (1.2 million km) from Ceres at the time. (image credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA) . ... Now itтАЩs a dwarf planet. (image credit: NASA/ESA/SWRI/Cornell University/University of Maryland/STSci) . ...

... Russian KOI8 . ... Radio galaxies and cosmology [in Russian]) . ... The book is devoted to investigations of powerful radio galaxies in the different wavelength ranges. ... The history of study for radio galaxies is given and the outlook on radio galaxy exploring is considered. ... The cosmological tests to check the Universe evolution parameters constructed on the observational data of radio galaxies are considered in details. ... List of detected misprints (in Russian). ...