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851.
F. De Tiberis L. Simone D. Gelfusa P. Simone R. Viola A. Santoni O. Cocciolillo M. Ziarelli F. Barletta N. Salerno M. Maffei V. Nanni 《Acta Astronautica》2011,68(5-6):591-598
This paper reports the main characteristics of the deep space transponder (DST) equipment that has been designed, developed and tested by Thales Alenia Space—Italy (TAS-I) for the European Space Agency (ESA) BepiColombo mission to Mercury. 相似文献
852.
The paper presents a novel noncertainty-equivalent adaptive (NCEA) control system for the pitch attitude control of satellites in elliptic orbits using solar radiation pressure (SRP). The satellite is equipped with two identical solar flaps to produce control moments. The adaptive law is based on the attractive manifold design using filtered signals for synthesis, which is a modification of the immersion and invariance (I&I) method. The control system has a modular controller–estimator structure and has separate tunable gains. A special feature of this NCEA law is that the trajectories of the satellite converge to a manifold in an extended state space, and the adaptive law recovers the performance of a deterministic controller. This recovery of performance cannot be obtained with certainty-equivalent adaptive (CEA) laws. Simulation results are presented which show that the NCEA law accomplishes precise attitude control of the satellite in an elliptic orbit, despite large parameter uncertainties. 相似文献
853.
M. N. Burdaev 《Cosmic Research》2011,49(5):464-467
The paper presents the derivation of two new equations for calculating the time of transfer between two points of the central
gravitational field: for hyperbolic orbits and the universal equation for elliptical and hyperbolic orbits. In the paper we
have used as an independent variable, instead of the linear elements (semimajor axis, focal parameter of orbit or a chord
connecting the ends of boundary radii of transfer), the angular parameter—the angle between the radius vector of an initial
point of transfer and the vector of initial velocity of transfer. Paper’s material is a continuation of that presented in
the “Space research“ Journal, vol. 2, March–April, 2009. 相似文献
854.
A. I. Tkachenko 《Cosmic Research》2011,49(2):150-159
A method to find and identify failures in a spacecraft’s set of sensitive elements that measure vector quantities of different
nature is discussed. 相似文献
855.
Hugh S. Hudson 《Space Science Reviews》2011,158(1):5-41
This article broadly reviews our knowledge of solar flares. There is a particular focus on their global properties, as opposed
to the microphysics such as that needed for magnetic reconnection or particle acceleration as such. Indeed solar flares will
always remain in the domain of remote sensing, so we cannot observe the microscales directly and must understand the basic
physics entirely via the global properties plus theoretical inference. The global observables include the general energetics—radiation
in flares and mass loss in coronal mass ejections (CMEs)—and the formation of different kinds of ejection and global wave
disturbance: the type II radio-burst exciter, the Moreton wave, the EIT “wave”, and the “sunquake” acoustic waves in the solar
interior. Flare radiation and CME kinetic energy can have comparable magnitudes, of order 1032 erg each for an X-class event, with the bulk of the radiant energy in the visible-UV continuum. We argue that the impulsive
phase of the flare dominates the energetics of all of these manifestations, and also point out that energy and momentum in
this phase largely reside in the electromagnetic field, not in the observable plasma. 相似文献
856.
E. M. Kraeva 《Russian Aeronautics (Iz VUZ)》2011,54(2):154-158
Based on the jet-vortex model for flow passage hydrodynamics in a high-speed centrifugal pump with the open-type impeller,
we present the calculated relations for design and optimization of the experimentally verified pump design parameters. 相似文献
857.
In this paper, one of the most possible methods for calculations of ejector devices equipped with the cylindrical mixing chambers
is considered; the method is based on averaging the flow parameters at the chamber inlet. We present the calculation results
and their comparison with the earlier published data, as well as the quantitative assessment of this method and feasibilities
of its use for different technical devices embodying the concept of ejection. 相似文献
858.
Some methods of optimizing a cutting tool kit by the minimum labour content criterion in milling of an article are considered.
Their advantages and disadvantages are given. 相似文献
859.
The scheme variants of implementing the thermal protection against heat flows being generated by the body of a high-temperature
stationary gas turbine engine (GTE) are presented. The scheme of the experimental bench with a working section is given. Methodical
approaches to the heat transfer calculation at different variants of forced and natural convection organization and under
various operating conditions are described. The generalized results of the experiments carried out using a heat curtain being
generated by porous injection are presented. 相似文献
860.
B. I. Mamaev 《Russian Aeronautics (Iz VUZ)》2011,54(2):159-164
Some design and experimental data on three cascades with the same 12° bending angle for the primary nozzle block of a gas
turbine are presented. As is seen from the investigation the most efficient at the transonic velocities of the outward flow
are the blades, the back curvature of which in the bevel cut zone decreases to the trailing edge. Also presented is the fact
that the blade with the increasing back curvature has noticeably larger losses. 相似文献