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601.
A. Labeyrie G. Schumacher E. Savaria 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1982,2(4):11-22
FLUTE and TRIO are two versions of a proposed optical interferometer, intended as a first step towards large optical arrays. The two apertures of FLUTE are linked by solid members, while TRIO relies totally upon active stabilization techniques to maintain optical coherence with three satellites serving as array components. The feasibility of utilizing solar radiation pressure for fine control is studied.A natural and periodic variation of baseline spacing can be achieved by certain orbital configurations. Thus, skin panels having a tunable reflectivity suffice to obtain the fine corrections needed. Preliminary modelling indicates adequate controllability for such “chameleon” satellites. If suitable panel types can be developed, a TRIO system employing them would be preferred to FLUTE type structures. The longer (1 to 10 km) baselines achievable are of particular interest and the cost is probably lower. 相似文献
602.
L. Dezső G. Csepura O. Gerlei Á. Kovács I. Nagy 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1984,4(7):57-60
Using full-disc white light photoheliograms, we have studied umbrae motion and variations in sunspot areas in a large activity complex over 4 solar rotations. On the basis of the observational data we illustrate with typical examples to what extent rapid spot motions are associated with flare occurrences. 相似文献
603.
604.
G. Stanev M. Petrunova D. Teodosiev I. Kutiev K. Serafimov S. Chapkunov V. Chmyrev N. Isaev P. Puschaev I. Pimenov S. Bilichanko 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1982,2(7):43-47
The instrument IESP-IPMP represents the complex unit measuring the vector of the DC electric field, the vectors of the electric and magnetic field in the frequency range of 0.2 – 6.5 Hz (wave form), autocorrelation functions of waves with frequencies of 0.1 – 5 kHz, and wave amplitudes in 8 bandpass channels. Some results are shown and compared in the various frequency ranges. 相似文献
605.
G.H. Schwehm R.H. Giese F. Giovane D.W. Schuerman J.L. Weinberg 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1981,1(8):121-125
The 1985 International Solar Polar Mission will provide the first opportunity to perform measurements from out of the ecliptic and from above the solar poles. Included in this mission is the Zodiacal Light/Background Starlight Experiment of the Ruhr-University Bochum, FRG (in collaboration with the State University of New York at Albany). The experiment is based on the use of a multicolor, sky-scanning photopolarimeter, which will be carried on the NASA S/C.The scientific objectives of the experiment are to investigate the intensity, polarization, and color of the diffuse sky brightness and determine the spatial distribution and physical properties of the interplanetary dust, including a possible interstellar component, as a function of S/C position in and out of the ecliptic.The instrument will allow simultaneous measurements in two separate wavelength bands. Measurements will be performed at 180, 220, 240, 280, 320, 350, 360, 440, 540, 640, 800 nm, including the state of polarization. Two different fields-of-view (1 sq deg and 5.6 sq deg) can be selected.The use of a microprocessor system in the instrument electronics will provide flexibility in measurement sequences and programs, on-board data processing and data quality control. 相似文献
606.
R.G. Walker H.H. Aumann 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1984,4(9):197-201
The large beam size of the Infrared Astronomy Satellite (IRAS) focal plane detector array is well suited to measuring the low level thermal emission from cometary dust. Eight comets discovered in 1983 and nine previously known periodic comets were observed by IRAS during its ten month active lifetime. Dust production rates are derived for a wide range of heliocentric distances. Grain properties are inferred from application of simple models to the long wavelength spectral energy distribution. 相似文献
607.
Johannsen K. Tustioson G. Egli S. 《IEEE transactions on aerospace and electronic systems》1980,(5):683-711
In many domestic satellite communication systems single-channel per-carrier FM (SCPC-FM) has become the accepted transmission method for thin route communication. The SCPC-FM modem operates over a wide range of carrier frequencies and is designed to use satellite power and bandwidth efficiently. It incorporates elements which make the signal transfer complex, so the system behavior is not immediately obvious. This article investigates the signal processes and analyzes the performance of a companded and preemphasized SCPC-FM system and it furnishes insight into the choice of crucial system parameters. 相似文献
608.
A general performance index is developed for evaluating aircraft landing trajectories. The primary term in the index is the effect of noise on people residing near the air terminal. Other terms included are passenger comfort, fuel consumed, and the time spent in the near-terminal area. Models are developed for aircraft engine noise, passenger comfort, the population distribution about a specific airport, and the aircraft flight behavior. While this performance index may be used in computing optimal trajectories, it is also useful for comparing nonoptimal trajectories which, for one reason or another, may be worthy of consideration. Some examples of such comparisons are included through simulations of landing. The aircraft considered is a Boeing 737. 相似文献
609.
The planetary radio astronomy experiment will measure radio spectra of planetary emissions in the range 1.2 kHz to 40.5 MHz. These emissions result from wave-particle-plasma interactions in the magnetospheres and ionospheres of the planets. At Jupiter, they are strongly modulated by the Galilean satellite Io.As the spacecraft leave the Earth's vicinity, we will observe terrestrial kilometric radiation, and for the first time, determine its polarization (RH and LH power separately). At the giant planets, the source of radio emission at low frequencies is not understood, but will be defined through comparison of the radio emission data with other particles and fields experiments aboard Voyager, as well as with optical data. Since, for Jupiter, as for the Earth, the radio data quite probably relate to particle precipitation, and to magnetic field strength and orientation in the polar ionosphere, we hope to be able to elucidate some characteristics of Jupiter auroras.Together with the plasma wave experiment, and possibly several optical experiments, our data can demonstrate the existence of lightning on the giant planets and on the satellite Titan, should it exist. Finally, the Voyager missions occur near maximum of the sunspot cycle. Solar outburst types can be identified through the radio measurements; when the spacecraft are on the opposite side of the Sun from the Earth we can identify solar flare-related events otherwise invisible on the Earth. 相似文献
610.
R.B. Stoltzfus S.A. Bowhill L.G. Smith 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1984,4(6):143-146
The Langmuir-probe technique for measurement of electron concentration in the mesosphere is capable of excellent altitude resolution, of order 1 m. Measurements from nine rocket flights frequently show small-scale ionization structures in the altitude region 60–90 km. These are believed to be identical with regions of strong coherent backscatter seem by VHF radars at Jicamarca, Peru and Urbana, Illinois. They are believed to represent intermittent turbulence attributable to nonlinear interaction of waves in the mesosphere. Parameters of the turbulent regions are estimated. 相似文献