仿真模拟技术在固体火箭发动机操作训练中的应用

从导弹部队操作训练的角度出发,论述了固体火箭发动机仿真模拟训练的必要性和可行性,以及设想的仿真模拟训练系统的组成和功用.     

Mars Direct: Humans to the red planet by 1999

“Mars Direct”, is an approach to the space Exploration Initiative that allows for the rapid initiation of manned Mars exploration, possibly as early as 1999. The approach does not require any on-orbit assembly or refueling or any support from the Space Station or other orbital infrastructure. Furthermore, the Mars Direct plan is not merely a “flags and footprints” one-shot expedition, but puts into place immediately an economical method of Earth-Mars transportation, real surface exploratory mobility, and significant base capabilities that can evolve into a mostly self-sufficient Mars settlement. This paper presents both the initial and evolutionary phases of the Mars Direct plan. In the initial phase, only chemical propulsion is used, sendig 4 persons on conjunction class Mars exploratory missions. Two heavy lift booster launches are required to support each mission. The first launch delivers an unfueled Earth Return Vehicle (ERV) to the martian surface, where it fills itself with methane/oxygen bipropellant manufactured primarily out of indigenous resources. After propellant production is completed, a second launch delivers the crew to the prepared site, where they conduct regional exploration for 1.5 years and then return directly to Earth in the ERV. In the second phase of Mars Direct, nuclear thermal propulsion is used to cut crew transit times in half, increase cargo delivery capacity, and to create the potential for true global mobility through the use of CO₂ propelled ballistic hopping vehicles (“NIMFs”). In this paper we present both phases of the Mars Direct plan, including mission architecture, vehicle designs, and exploratory strategy leading to the establishment of a 48 person permanent Mars base. Some speculative thoughts on the possibility of actually colonizing Mars are also presented.     

Drying as one of the extreme factors for the microflora of the atmosphere

An investigation of the effects of drying and drying-rewetting cycles under vacuum conditions of 10(-2) torr at -30 degrees C on conidia of the atmospheric strain Penicillium chrysogenum from 48-77 km heights, collected by meteorological rockets found that survival and restoration of the initial physiological properties were possible through some very efficient protective cellular mechanisms. Such adaptive possibilities explain the widespread diffusion of microbial cells throughout the biosphere of our planet.     

The past and future of the earth-moon system

The lunar orbit is presently expanding due, we believe, to tidal friction, i.e. the attraction of the moon for the tides it raises on the rotating Earth. The Moon may therefore have been significantly closer to the Earth in the distant past, a point of great interest to those studying the lunar origin. This work presents the results of the integration of the equations which govern the rates of change of the lunar orbit elements and the angular momentum of the Earth. Results are presented for both the past and future of the Earth-Moon system.     

Anesthesia, surgical aid and resuscitation in manned space missions.

When discussing problems related to medical service in space flight, particular attention should be given to the specific living conditions and changes associated with space flight. In disease and injury, surgery can be provided only after conservative therapy has failed. In this context gnotobiological chambers allowing surgery in aseptic conditions seem promising. A portable set of interchangeable surgical tools should be made of light-weight alloys that can be readily sterilized. Electroanalgesia in combination with auriculoacupuncture as well as peridureal anesthesia may be used as they allow normal operations in autonomous space flight conditions. Changes in the sympatho-adrenal and kallikrein-kinin systems, as well as water-electrolyte balance, should be taken into account in developing methods and means of medical service in critical situations. Special attention should be given to the prevention and treatment of brain edema in view of weightlessness-induced cephalad fluid shifts.     

Phugoid oscillations in optimal reentry trajectories

A major problem with operations of lifting reentry vehicle having an aft center-of-gravity location due to large engine mass at the rear is the required hypersonic trim to fight the desired trajectory. This condition is most severe for lifting maneuvers. As a first step toward analyzing this problem, this paper considers the lift requirement for some basic maneuvers in the plane of a great circle. Considerations are given to optimal lift control for achieving the maximization of either the final altitude, speed or range. For the maximum-range problem, phugoid oscillation along an optimal trajectory is less severe as compared to a glide with maximum lift-to-drag ratio. An explicit formula for the number of oscillations for an entry from orbital speed is proposed.     

含碳酸钙的负压强指数复合固体推进剂燃烧机理

本文采用激光阴影高速摄影、扫描电子显微镜、X光电子能谱,对含和不含CaCO_(3)的三种夹心件及SO4-5A PU复合推进剂的燃烧过程、燃面形貌、化学成分和覆盖分数分别进行了研究和测定。结果表明:CaCO_(3)在低压下(〈1.96MPa)提高AP的燃速,在高压下(〉1.96MPa)起降速作用;CaCO_(3)与AP反应生成CaCl_2,并促使AP熔化;燃面上CaCl_2含量随压强上升而增加;PU熔化流动对AP表面的覆盖在mesa区内随压强而升高,在非mesa区的低压区也存在。基于以上实验结果,对含CaCO_(3)的PU负压强指数推进剂的燃烧机理进行了讨论。     

International cooperation in assuring continuity of environmental satellite data

In the 25 years since the launch of the first weather satellite, meteorological observations from space have become an essential part of weather forecasting and global environmental monitoring. Beginning in the 1970s, constrained national budgets and the need for a coordinated approach to global satellite observing have caused satellite operators to pursue international cooperation to assure the continuity and compatibility of these systems. This article reviews current bilateral and multilateral cooperation and technical coordination in environmental satellite activities. It also explores the potential for alternative institutional arrangements for maintaining the continuity of environmental satellite data in the decades to come.     

"Signal" search for intelligence in the galactic nucleus with the array of the Lowlands

In August, 1981, the Westerbork Synthesis Radio Telescope was used for 4 h to search for narrowband pulsing radio beacons in the direction of the Galactic Center. By using both the spatial discrimination and temporal stability available to an interferometric measurement, weak intermittent signals can be detected even in the face of the strong, naturally caused radiation from this region. A radio beacon within our bandwidth, centered on the 21 cm neutral hydrogen line, would be recognizable if it had a repetition period between 40 sec and 1/2 h. The rms sensitivity to point sources was approximately 50 mJy/cycle, and the detection limit was 500 mJy/cycle. The limit degrades for pulse widths < 0.02s. No repetitive signals were found. For a swept, narrow-band radio beacon constrained to the Galactic Disk (beamwidth = 0.02 rad), our detection limit corresponds to a transmitter power of 10(11) MW at the Galactic Center.     

Control of an orbiting flexible square platform in the presence of solar radiation

A mathematical model for the solar radiation forces and moments acting on a square plate (platform) in orbit is obtained by considering the plate mode shapes as combinations of free-free beam shape functions. The moment expressions for a plate of arbitrary reflectivity coefficient are obtained as a function of the solar incidence angle. It is seen that only the first three flexible modes of the plate generate a first order net moment about the center of mass, and that the solar radiation pressure does not influence the flexible modes of the plate for small amplitude vibrations. The solar radiation disturbance model is then included in the dynamic model of a square plate nominally oriented along the local vertical and having the major surface of the plate normal to the orbital plane. The roll angle of the plate is seen to increase steadily due to the solar radiation pressure whereas the pitch and yaw motions oscillate with an amplitude of approximately 0.2° for a 100 m square thin aluminum plate in synchronous orbit. To control the shape and orientation of the plate two point actuators are assumed—one whose force axis is normal to the plane of the plate, the second with a force axis in the plane of the plate. The control law and the feedback gain values are obtained based on linear quadratic Gaussian methods. Transient responses and control requirements are simulated for local vertical and horizontal orientations.