Solar particle events and the International Space Station

The high inclination orbit for the International Space Station poses a risk to astronauts on EVA during occasional periods of enhanced high energy particle flux from the sun known as Solar Particle Events. We are currently unable to predict these events within the few-hour lead time required for evasive action. Compounding the threat is the fact that station construction occurs during increasing solar activity and through the peak of the solar cycle. In this paper we present an overview of the risk, the current methods to provide forecasts of SPEs, and potential risk mitigation options.     

卫星:所有通信业务发展的必由之路

1　概述□□未来航天活动的特点是,建造卫星星座,开展新业务及新应用,增强运载火箭推力。还应当考虑为地面通信网开发有关技术,满足用户不断增长的需求。为了对上述变化作好准备,乃至采取未雨绸缪的行动,阿尔卡特航天公司(AlcatelSpace)已经对其组织结构进行了变动。1998年,阿尔卡特公司卫星业务部和法国宇航公司及汤姆逊-CSF公司合并,组建了拥有近6000名员工的AlcatelSpace。目前,这家世界主要的卫星制造商从事两种主要的活动:1制造由阿尔卡特航天工业公司(AlcatelSpaceIndustries)负责;2运行和业务由阿尔卡特空间通信公司(AlcatelSpa…     

Antibody engineering--a valuable asset in preventing closed environment epidemics

Investigations of Mir, Space Shuttle, Skylab and Apollo missions report extensive colonisation of the spacecraft by bacteria and fungi, which can lead to degradative effects on spacecraft equipment and devastating effects on space-grown crops. More than 80% of terrestrial greenhouse epidemics are due to the fungal genera Phytophthora, Pythium and Fusarium, which have been found in life support system test-beds. The advent of recombinant antibody technologies, including ribosome display and phage display, has made it possible to develop antibodies against virtually any toxin or organism and allows for maturation of antibodies by in vitro molecular evolution. These antibodies may play an important role in an integrated pest management regime for life support systems. Efficacy of existing fungal countermeasures could be increased by chemical linkage to antibodies, which target the site of action of the biocide or trap the pathogen in a biofilter. Novel recombinant antibody-biocide fusions can be expressed in situ by plants or symbiotic microbes to create direct disease resistance.     

Entrapment of bacteria in fluid inclusions in laboratory-grown halite

Cells of the bacterium Pseudomonas aeruginosa, which were genetically modified to produce green fluorescent protein, were entrapped in fluid inclusions in laboratory-grown halite. The bacteria were used to inoculate NaCl-saturated aqueous solutions, which were allowed to evaporate and precipitate halite. The number, size, and distribution of fluid inclusions were highly variable, but did not appear to be affected by the presence of the bacteria. Many of the inclusions in crystals from inoculated solutions contained cells in populations ranging from two to 20. Microbial attachment to crystal surfaces was neither evident nor necessary for entrapment. Cells occurred exclusively within fluid inclusions and were not present in the crystal matrix. In both the inclusions and the hypersaline solution, the cells fluoresced and twitched, which indicates that the bacteria might have remained viable after entrapment. The fluorescence continued up to 13 months after entrapment, which indicates that little degradation of the bacteria occurred over that time interval. The entrapment, fluorescence, and preservation of cells were independent of the volume of hypersaline solution used or whether the solutions were completely evaporated prior to crystal extraction. The results of this study have a wide range of implications for the long-term survival of microorganisms in fluid inclusions and their detection through petrography. The results also demonstrate the preservation potential for microbes in hypersaline fluid inclusions, which could allow cells to survive harsh conditions of space, the deep geologic past, or burial in sedimentary basins.     

Space motion sickness preflight adaptation training: preliminary studies with prototype trainers

Preflight training frequently has been proposed as a potential solution to the problem of space motion sickness. The paper considers successively the otolith reinterpretation, the concept for a preflight adaptation trainer and the research with the Miami University Seesaw, the Wright Patterson Air-Force Base Dynamic Environment Simulator and the Visually Coupled Airborne Systems Simulator prototype adaptation trainers.     

Recent SETI observations at Arecibo

During 1980 and 1981, the 305-m radio telescope at the Arecibo Observatory in Puerto Rico was used to conduct a high resolution search for narrowband signals from the direction of 210 nearby solar type stars and 5 OH masers. For each star at least 4 MHz of bandwidth surrounding the 21-cm HI line and/or the 18-cm OH lines was studied with a spectral resolution of 5.5 Hz in both right and left circular polarization. The formal limit of sensitivity achieved during the course of this search varied depending upon the particular receivers available. In all cases the search could have detected a narrowband transmitter of power comparable to the Arecibo planetary radar, had any such been transmitting on the frequencies searched during the time of observation out to the distance of the farthest target star. As in previous searches, the number of "false alarms" encountered was far greater than predicted on the basis of Gaussian noise statistics. A small number of stars have exhibited signals which cannot immediately be explained in terms of astrophysical or man-made sources and deserve reobservation. This is typical of the results of previous non-real-time searches and does not yet constitute the detection of an ETI.