The results of processing and interpreting the data of joint Russian–French experiments for studying the heat and mass transfer in near-critical fluids are presented. The experiments were carried out with the ALICE-1 instrument during an orbital flight of the Mirstation from September 30 to October 2, 1995 [1]. For such fluids with a point-like source of heat, when they are placed in the field of uncontrolled inertial accelerations of the spacecraft, the influence of thermovibrational and thermogravitational mechanisms of convection on the propagation of the region of optical irregularity is investigated. It is shown that, near the thermodynamic critical point, local heating of the medium leads to generation of either intense thermogravitational convection or averaged vibroconvective flow, depending on the frequency of variations of the microaccelerations. The structure and characteristics of discovered motions are studied. The results of numerical simulations are presented that confirm the conclusion about a possibility of generation of an averaged convective flow of a vibrational type by the high-frequency component of microaccelerations. 相似文献
Earth's subsurface offers one of the best possible sites to search for microbial life and the characteristic lithologies that life leaves behind. The subterrain may be equally valuable for astrobiology. Where surface conditions are particularly hostile, like on Mars, the subsurface may offer the only habitat for extant lifeforms and access to recognizable biosignatures. We have identified numerous unequivocally biogenic macroscopic, microscopic, and chemical/geochemical cave biosignatures. However, to be especially useful for astrobiology, we are looking for suites of characteristics. Ideally, "biosignature suites" should be both macroscopically and microscopically detectable, independently verifiable by nonmorphological means, and as independent as possible of specific details of life chemistries--demanding (and sometimes conflicting) criteria. Working in fragile, legally protected environments, we developed noninvasive and minimal impact techniques for life and biosignature detection/characterization analogous to Planetary Protection Protocols. Our difficult field conditions have shared limitations common to extraterrestrial robotic and human missions. Thus, the cave/subsurface astrobiology model addresses the most important goals from both scientific and operational points of view. We present details of cave biosignature suites involving manganese and iron oxides, calcite, and sulfur minerals. Suites include morphological fossils, mineral-coated filaments, living microbial mats and preserved biofabrics, 13C and 34S values consistent with microbial metabolism, genetic data, unusual elemental abundances and ratios, and crystallographic mineral forms. 相似文献
A method for approximate analytical optimization of low-thrust transfers, described in [1] and based on linearization of the equations of motion, is considered. A more precise method of reducing the errors due to linearization is suggested. The method of optimization is generalized for the case of a mission to several celestial bodies. 相似文献
Over the past several hundred years, many ideas have been expressed as to how human beings might communicate with extraterrestrials. These ideas have been put forth by experts from a diverse range of fields including physical scientists, mathematicians, behavioral scientists, philosophers and creative writers who have widely differing views on how to express ourselves coherently with civilizations from other worlds.This paper will look at some of these differing viewpoints and stress the need for an inter-disciplinary approach to the challenges of sending and, perhaps most important, receiving messages. Could we decipher a message if we got one? Who is doing the listening and what advantages could an inter-disciplinary approach bring to these efforts? What are some inter-disciplinary approaches to sending messages to extraterrestrials? 相似文献
The National Aeronautics and Space Administration (NASA) New Millennium Program (NMP) is a technology development and validation program that will flight-validate advanced, new technologies with space flight applications. NMP's purpose is twofold. First, it will develop technologies that will enable future spacecraft to be smaller, more capable and reliable, and to be launched more frequently. Second, it will validate the technologies in flight to reduce the risks to future science missions that fly these technologies for the first time. To measure the program's success, NMP has devised a set of criteria that stresses the relevance of technologies selected for flight validation to NASA's 21st-century science mission needs. Also, NMP has instituted a ‘risk management’ policy, where, through a combination of adequate resources and early risk assessment and risk mitigation plans for the technologies, the overall risk of the NMP flights can be rendered acceptable. 相似文献
Here are reported preliminary results of the “Synergy” experiment performed aboard the Russian orbital station “MIR” in July 1993 (Altaïr Mission). The experiment was carried out before, during, and after the space flight of two astronauts (S1 and S2). The duration of the flight was 21 days for S1 and 6 month for S2. The subjects were tested during preflight, inflight and postflight. The astronaut subjects were fixed on the ground by the feet. They were asked to pick up a box in front of them on the ground. Two velocities of movement and two distances of the target to be reached were tested. The movement of several small markers placed on the body was recorded on video tape.
Results show that the shape of head and hand trajectories in the sagittal plane remains roughly the same during the flight in spite of the modification of mechanical constraints. Trajectory invariance does not result in joint angular displacement invariance. These data indicate that the planning of the movement takes place in terms of head and hand trajectories rather than joint rotations as it was previously suggested for simple arm reaching movement. 相似文献
The mission's success fully depends on the Payload Operations conducted during the space flight. The Ground Team has to be trained to assist the Space Crew, to replan the cosmonaut's activities when contingengies occurr onboard and to change or cancel Payload activities when required. In order to act efficiently during the mission, the Ground Team must be prepared in advance of the flight and able to operate special tools for tracking the mission's progress, anticipating problems and taking decisions in realtime.
This document sets out the approach for conducting such a preparation for Ground Operation. It will be focused on the Altaïr mission performed in July 1993 onboard the Russian Mir space station. 相似文献
This remote assistance trial, performed within the framework of the manned space flight Altaïr, was carried out by CADMOS (CNES), with the cooperation of the Sub-directorate of CNES Operational Systems, Medes, LBM of Tours and Christol Consultants. It consisted of supplying the cosmonaut performing the Orthostatism experiment (echograph acquisition) on board the Mir station with realtime assistance by an expert (LBM of Tours) working from the ground on the CADMOS premises. The various steps of the approach followed during the preparation phase are described, as well as the technical means of communication used between the Mir station and CADMOS. 相似文献
There is a concern in the developing world that industrialized countries have not done all they might under Article 1 of the Outer Space Treaty to make the benefits of space technology available to all countries; some are now seeking codification of rights and responsibilities in this sphere. This article discusses recent debate on the issues by COPUOS and its Legal Subcommittee on whether an additional legal framework is necessary to ensure a fairer distribution of benefits. G77 countries were strongly in favour of some form of technology and information transfer, while industrialized countries favoured the existing practice of developing international cooperative space projects. The author believes that a new set of principles will be formulated in the next few years and that organizations like Intelsat and Inmarsat can provide valuable models for ensuring access through cooperative programmes. 相似文献