Variations in fluxes of quasi-trapped energetic protons were studied on the basis of the data of the CORONAS-I satellite. These variations are characterized by an increase in the proton fluxes with EP ≥ 1 MeV both in the vicinity of the geomagnetic equator and in the high-latitude region of the magnetosphere. The analysis of structural features of the proton distributions in the regions at L ~ 1–1.1; 3 < L < 4; and L > 4, was performed and made it possible to detect reliably the type of the proton flux increase in this region. The mechanisms of particle scattering leading to the precipitation of energetic protons under conditions of various types of geomagnetic disturbances are considered. 相似文献
The large-size frame of space ship and space station can be created with the use of the technology of the polymerization of fiber-filled composites and a liquid reactionable matrix applied in free space or on the other space body when the space ship or space station will be used during a long period of time. For the polymerization of the station frame the fabric impregnated with a long-life polymer matrix (prepreg) is prepared in terrestrial conditions and, after folding, can be shipped in a compact container to orbit and kept folded on board the station. In due time the prepreg is carried out into free space and unfolded. Then a reaction of matrix polymerization starts. After reaction of polymerization the durable frame is ready for exploitation. After that, the frame can be filled out with air, the apparatus and life support systems. The technology can be used for creation of biological frame as element of self regulating ecological system, and for creation of technological frame which can be used for a production of new materials on Earth orbit in microgravity conditions and on other space bodies (Mars, Moon, asteroids) for unique high price mineral extraction. Based on such technology a future space base on Earth orbit with volume of 10(6) m3 and a crew of 100 astronauts is considered. 相似文献
Further development of an approximate method for optimizing a flight with an ideally controlled small thrust is proposed. The method is based on the employment of the transporting trajectory and considered in [1–3]. A detailed analysis of the means of improving the accuracy of this method suggested in [2, 3] is carried out, and the solution is presented in finite form. The proposed approach is applied to the flights making flybys of many celestial bodies. In the case of small bodies the solution is also obtained in finite form. A numerical example is considered confirming the high efficiency of this method. 相似文献
Radar return data from airborne jet aircraft were collected and analyzed to determine the presence of consistent, dominant radar returns of point scatterers on aircraft simulating landing conditions. These measurements were performed by integrating two separate X-band radars into one system with the ability to simultaneously track and image aircraft. Selected processed data from both radar systems were analyzed and are presented for the airborne jet aircraft 相似文献
Although the Mars Express (MEX) does not carry a magnetometer, it is in principle possible to derive the interplanetary magnetic
field (IMF) orientation from the three dimensional velocity distribution of pick-up ions measured by the Ion Mass Analyser
(IMA) on board MEX because pick-up ions' orbits, in velocity phase space, are expected to gyrate around the IMF when the IMF
is relatively uniform on a scale larger than the proton gyroradius. During bow shock outbound crossings, MEX often observed
cycloid distributions (two dimensional partial ring distributions in velocity phase space) of protons in a narrow channel
of the IMA detector (only one azimuth for many polar angles). We show two such examples. Three different methods are used
to derive the IMF orientation from the observed cycloid distributions. One method is intuitive (intuitive method), while the
others derive the minimum variance direction of the velocity vectors for the observed ring ions. These velocity vectors are
selected either manually (manual method) or automatically using simple filters (automatic method). While the intuitive method
and the manual method provide similar IMF orientations by which the observed cycloid distribution is well arranged into a
partial circle (representing gyration) and constant parallel velocity, the automatic method failed to arrange the data to
the degree of the manual method, yielding about a 30° offset in the estimated IMF direction. The uncertainty of the derived
IMF orientation is strongly affected by the instrument resolution. The source population for these ring distributions is most
likely newly ionized hydrogen atoms, which are picked up by the solar wind. 相似文献
In this paper we describe a three-dimensional, multicellular tissue-equivalent model, produced in NASA-designed, rotating wall bioreactors using mammalian cells engineered for genomic containment of multiple copies of defined target genes for genotoxic assessment. Rat 2 lambda fibroblasts, genetically engineered to contain high-density target genes for mutagenesis (Stratagene, Inc., Austin, TX), were cocultured with human epithelial cells on Cytodex beads in the High Aspect Ratio Bioreactor (Synthecon, Inc, Houston, TX). Multi-bead aggregates were formed by day 5 following the complete covering of the beads by fibroblasts. Cellular retraction occurred 8-14 days after coculture initiation culminating in spheroids retaining few or no beads. Analysis of the resulting tissue assemblies revealed: multicellular spheroids, fibroblasts synthesized collagen, and cell viability was retained for the 30-day test period after removal from the bioreactor. Quantification of mutation at the LacI gene in Rat 2 lambda fibroblasts in spheroids exposed to 0-2 Gy neon using the Big Blue color assay (Stratagene, Inc.), revealed a linear dose-response for mutation induction. Limited sequencing analysis of mutant clones from 0.25 or 1 Gy exposures revealed a higher frequency of deletions and multiple base sequencing changes with increasing dose. These results suggest that the three-dimensional, multicellular tissue assembly model produced in NASA bioreactors are applicable to a wide variety of studies involving the quantification and identification of genotoxicity including measurement of the inherent damage incurred in Space. 相似文献
The Scanning Sky Monitor (SSM) on ASTROSAT is a position-sensitive gas-filled proportional counter with a wide field of view. The scientific objective of SSM is to scan the sky within few hours to detect and locate transient X-ray sources in the outburst phase. Once detected, this information will be provided for studies in all energy bands. The energy range of operation of SSM is 2–10 keV. The optimisation of the parameters of the proportional counter such as the cell size, the gas mixture and the gas pressure for the SSM are discussed here. 相似文献
Testing of hardware packages of sensors, actuators, and control electronics in the control loop for the IRS and SROSS satellites using motion simulators is reported. Simulation exercises and test results are described. Both air-bearing platforms and servo tables were used. The problems observed varied from interface incompatibilities and logic-level mistakes to onboard software malfunctions. unit-to-unit differences, and controller gain parameters. The importance of testing with hardware in a dynamic environment, is demonstrated 相似文献
One of the main guidelines for future X-ray astronomy projects like, e.g., XEUS (ESA) and Generation-X (NASA) is to utilize grazing-incidence focusing optics with extremely large telescopes (several tens of m2 at 1 keV), with a dramatic increase in collecting area of about two order of magnitude compared to the current X-ray telescopes. In order to avoid the problem of the source's confusion limit at low fluxes, the angular resolution required for these optics should be superb (a few arcsec at most). The enormous mirror dimensions together with the high imaging performances give rise to a number of manufacturing problems. It is basically impossible to realize so large mirrors from closed Wolter I shells which benefit from high mechanical stiffness. Instead the mirrors need to be formed as rectangular segments and a series of them will be assembled in a petal. Taking into account the realistic load capabilities of space launchers, to be able to put in orbit so large mirror modules the mass/geometric-area ratio of the optics should be very small. Finally, with a so large optics mass it would be very difficult to provide the electric power for an optics thermal active control, able to maintain the mirrors at the usual temperature of 20 °C. Therefore, very likely, the optics will instead operate in extreme thermal conditions, with the mirror temperature oscillating between −30 and −40 °C, that tends to exclude the epoxy replication approach (the mismatch between the CTE of the substrate and that of the resin would cause prohibitively large deformations of the mirror surface profiles). From these considerations light weight materials with high thermal–mechanical properties such as glass or ceramics become attractive to realize the mirrors of future Xray telescopes. In this paper, we will discuss a segments manufacturing method based on BorofloatTM glass. A series of finite element analysis concerning different aspects of the production, testing and integration of the optics are also presented as well. 相似文献
Presently, the french governmental bodies and space industry are joining their efforts and investments in a large technological programme named STENTOR; this programme is aiming to improve competitiveness of french space telecom industry by lowering costs and getting quickly vital technologies for the future.
First of all, this paper outlines main components of this programme and its major stages since 1994 up to 2009. Most innovating technologies of STENTOR satellite are described in terms of technical performances, development status and very promising impacts on cost and overall performances of future commercial telecom satellites; here is a preliminary list: plasma propulsion, thermal control using fluid loops and a deployable radiator, Li-Ion batteries, orbit determination with GPS receiver. Ku band regenerative payload with active antennas, etc.
Finally, some examples of service demonstrations foreseen for the in-orbit operating phase are given as illustrations. 相似文献