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271.
J.-P. Delaboudiniere R.A. Stern A. Maucherat F. Portier-Fozzani W.M. Neupert J.B. Gurman R.C. Catura J.R. Lemen L. Shing G.E. Artzner J. Brunaud A.H. Gabriel D.J. Michels J.D. Moses B. Au K.P. Dere R.A. Howard R. Kreplin J.M. Defise C. Jamar P. Rochus J.P. Chauvineau J.P. Marioge F. Clette P. Cugnon E.L. Van Dessel 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1997,20(12):2231-2237
The SOHO (SOlar and Heliospheric Observatory) satellite was launched on December 2nd 1995. After arriving at the Earth-Sun (L1) Lagrangian point on February 14th 1996, it began to continuously observe the Sun. As one of the instruments onboard SOHO, the EIT (Extreme ultraviolet Imaging Telescope) images the Sun's corona in 4 EUV wavelengths. The He II filter at 304 Å images the chromosphere and the base of the transition region at a temperature of 5 − 8 × 104 K; the Fe IX–X filter at 171 Å images the corona at a temperature of 1.3 × 106 K; the Fe XII filter at 195 Å images the quiet corona outside coronal holes at a temperature of 1.6 × 106 K; and the Fe XV filter at 284 Å images active regions with a temperature of 2.0 × 106 K. About 5000 images have been obtained up to the present. In this paper, we describe also some aspects of the telescope and the detector performance for application in the observations. Images and movies of all the wavelengths allow a look at different phenomena present in the Sun's corona, and in particular, magnetic field reconnection. 相似文献
272.
K Dose A Bieger-Dose R Dillmann M Gill O Kerz A Klein C Stridde 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1996,18(12):51-60
The response of spores of Bacillus subtilis, cells of Deinococcus radiodurans and conidia of Aspergillus ochraceus to actual and simulated space conditions (UV in combination with long-term exposure to extremely dry conditions, including vacuum) has been studied: The following effects have been analyzed: decrease of viability, occurrence of DNA double strand breaks, formation of DNA-protein cross-links and DNA-DNA cross-links. All organisms show an increased sensitivity to UV light in extreme dryness (dry argon or vacuum) compared to an irradiation in aqueous suspension. The UV irradiation leads in all cases to a variety of DNA lesions. Very conspicuous is the occurrence of double strand breaks. Most of these double strand breaks are produced by incomplete repair of other lesions, especially base damages. The increase in DNA lesions can be correlated to the loss in viability. The specific response of the chromosomal DNA to UV irradiation in extreme dryness, however, varies from species to species and depends on the state of dehydration. The formation of DNA double strand breaks and DNA-protein cross-links prevails in the case of B. subtilis spores. In cells of Deinococcus radiodurans DNA-DNA cross-links often predominate, in conidia of Aspergillus ochraceus double strand breaks. The results obtained by direct exposure to space conditions (EURECA mission and D2 mission) largely agree with the laboratory data. 相似文献
273.
A.C. Levasseur-Regourd 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1996,17(12):117-122
In-situ space observations of dust in the solar system are seldom possible. On the opposite, remote observations of solar light scattered by dust are relatively easy to perform from Earth- or satellite-based observatories; the evolution of the polarization of light scattered by dust particles as a function of the phase angle may provide information on the physical properties of these particles. Unfortunately, since remote observations are integrated along the line-of-sight of the observer, they can hardly be used to determine local physical properties. We have precisely developed Optical Probe techniques to forge the link between the numerous remote observations and the unique in-situ measurements. A short review of the remote observations of light scattered by cometary dust is first presented. Then, the Optical Probe concept is analyzed. Finally, the OPE instrument, which had been designed to optically probe the inner coma of comet Halley is described; its limitations and its achievements during Halley and Grigg-Skjellerup encounters are discussed. 相似文献
274.
M A Schneegurt B Arieli S S Nielsen P R Trumbo L A Sherman 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1996,18(4-5):177-180
Controlled ecological life support systems (CELSS) have been proposed to make long-duration manned space flights more cost-effective. Higher plants will presumably provide food and a breathable atmosphere for the crew. It has been suggested that imbalances between the CO2/O2 gas exchange ratios of the heterotrophic and autotrophic components of the system will inevitably lead to an unstable system, and the loss of O2 from the atmosphere. Ratio imbalances may be corrected by including a second autotroph with an appropriate CO2/O2 gas exchange ratio. Cyanothece sp. ATCC 51142 is a large unicellular N2-fixing cyanobacterium, exhibiting high growth rates under diverse physiological conditions. A rat-feeding study showed the biomass to be edible. Furthermore, it may have a CO2/O2 gas exchange ratio that theoretically can compensate for ratio imbalances. It is suggested that Cyanothece spp. could fulfill several roles in a CELSS: supplementing atmosphere recycling, generating fixed N from the air, providing a balanced protein supplement, and protecting a CELSS in case of catastrophic crop failure. 相似文献
275.
Yu. I. Yermolaev A. A. Petrukovich L. M. Zelenyi 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2002,30(12):2695-2700
We use ion distribution measurements with CORALL instrument on-board the INTERBALL/Tail spacecraft to study plasma flows in the mid-tail (−9> X> −27 RE) plasma sheet. Three velocity components computed every 2 minutes exhibit two types of velocity variations: Earthward bursty bulk flows (BBFs) and random flow fluctuations. Their properties are in a good agreement with the observations of the ISEE-2 spacecraft (Borovsky et al., 1997). The INTERBALL/Tail spacecraft configuration favors measurements of Vz component, in contrast to previous experiments in which only Vx and Vy were measured reliably. In the outer part of the plasma sheet Vy and Vz fluctuations were close to each other (variances σ(Vy) and σ(Vz) were about 160 and 110 km/s, respectively), but in the inner part at the dusk flank amplitude of Vy fluctuations increased and was 2 times higher than that of Vz component. This asymmetry of fluctuations should be taken into account during modern theoretical analysis and simulations. 相似文献
276.
P.S. Babcock D.M. Auslander R.C. Spear 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1984,4(12):263-270
Reliability of closed life support systems will depend on their ability to continue supplying the crew's needs in the face of perturbations and equipment failures. These dynamic considerations interact with the basic static (equilibrium) design through the sizing of storages, the specification of excess capacities in processors, and the choice of system initial state (total mass in the system). This paper uses a very simple system flow model to examine the possibilities for system failures even when there is sufficient storage to buffer the immediate effects of the perturbation. Two control schemes are shown which have different dynamic consequences in response to component failures. 相似文献
277.
G. Smoot G. De Amici S.D. Friedman C. Witebski N. Mandolesi R.B. Partridge G. Sironi L. Danese G. De Zotti 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1984,3(10-12)
New measurements of the Cosmic Background Radiation temperature at 12 cm, 6.3 cm, 3 cm, 0.9 cm and 0.3 cm have made in July 1982 from the White Mountain High Altitude Research Station. The results are presented and the existence of spectral distortions discussed. 相似文献
278.
Jill C. Tarter 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1986,6(12):219-226
A series of Workshops on Exobiology in Earth Orbit held at NASA Ames Research Center has recently concluded. The draft of the final report from these Workshops contains a prioritized list of telescopic observations (possible only from above the Earth's atmosphere) that relate to the origin and evolution of the biogenic elements and compounds from their nucleosynthetic creation within stars to their inclusion in living systems. These orbital observations and the ground based laboratory and theoretical research necessary to support them have been termed Observational Exobiology. The details available on spacecraft, platforms and instrumentation most likely to be launched in the near future by the U.S. and Europe were considered in the Workshops. The purpose was to determine what observational programs would be tractible and what area of interest to exobiology required hardware and/or mission capabilities not yet envisioned. This paper summarizes the exciting opportunities that exist for Observational Exobiology. 相似文献
279.
R A Binot C Tamponnet C h Lasseur 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1994,14(11):71-74
The anticipated evolution of life support technologies for ESA, considering both the complementary life support system requirements and the missions' characteristics, is presented. Based on these results, promising biological life support technologies for manned space missions have been selected by ESA either for their intrinsic ability and performance in effecting specific tasks for atmosphere-, water-, waste-management versus physico-chemical alternatives and/or for longer-term application to a more ecological concept (CES) focusing ultimately on food production. Actual status and plan for terrestrial and space testing of biological life support presented focusing on the "task specific" decontamination technology of the Biological Air Filter (BAF), and on food reprocessing technologies from biodegradable wastes with the MELISSA microbial ecosystem. 相似文献
280.
R. Jager J. Heise J. J. M. in ''t Zand A. C. Brinkman 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1993,13(12):315-318
SAX is an Italian X-ray satellite with a Dutch contribution that will be placed in orbit in 1994. The prime scientific object of SAX is to cover an energy bandwidth that ranges from 0.1 keV up to 200 keV. Among other instruments, SAX will consist of two X-ray Wide Field Cameras built by the Space Research Organisation Netherlands at Utrecht. The WFCs are based on the coded mask principle, the reconstruction of the image takes place on ground. The field of view is 20 degrees square full width at half maximum (FWHM), the angular resolution 5 arcminutes (FWHM) and the energy band ranges from 1.8 to 30 keV with a resolution of 18% at 6 keV. The sensitive area is 200 cm2 at 6 keV. The mask pattern is based on a pseudo random array with 255 × 257 elements of 1 mm2, 50% of which are transparent. 相似文献