Mineral and nitrogen balance study: results of metabolic observations on Skylab II 28-day orbital mission

Prediction that the various stresses of flight, particularly weightlessness, would bring about significant derangements in the metabolism of the musculoskeletal system has been based on various observations of long-term immobilized or inactive bed rest. The only attempt at controlled measurement of metabolic changes in space prior to Skylab, a study during the 14-day Gemini VII flight, revealed rather modest losses of important elements. The three astronauts of Skylab II consumed a planned day-by-day, quite constant, dietary intake of major metabolic elements in mixed foods and beverages and provided virtually complete collections of excreta for 31 days preflight, during the 28 days inflight, and for 17 days postflight. Analyses showed that, in varying degree among the crewmen, urinary calcium increased gradually during flight in a pattern similar to that observed in bed-rest studies: the mean plateau peak of urinary calcium excretion in the latter part of flight was double preflight levels. Fecal calcium excretion did not change significantly, but calcium balance, owing to the urinary calcium rise, became either negative or less positive than in preflight measurement. Increased excretion and negative balance of nitrogen and phosphorus indicated appreciable loss of muscle tissue in all three crewmen. Significant losses also occurred inflight in potassium, sodium, and magnesium. Based on the similarity in pattern and degree between these observations and those in bed rest of the losses in calcium, phosphorus, and nitrogen, musculoskeletal integrity would not be threatened in space flights of up to at least 3 months. However, if similar changes occur, indicative of continuing losses of these elements, in the planned Skylab flights for considerably more than 28 days, concern for capable musculoskeletal function should be serious for flights of very many months' duration, and greater research attention will need to be given to development of protective counter-measures.     

Soviet proposals on the militarization of space

The USSR has submitted several proposals to the United Nations in recent years which are aimed at avoiding the militarization of outer space. This article examines three of the proposals and evaluates them in the context of existing treaties, to see whether or not they could resolve the political and legal problems which might arise. The reactions of the United Nations General Assembly and individual nations are also considered. The author concludes that several questions regarding the military aspects of space activity are left unresolved by the Soviet proposals.     

二硝酰胺铵(ADN)球形化工艺研究

介绍了近年来国外关于二硝酰胺铵（ADN）球形化的工艺方法，重点讨论了中间介质、分散剂、表面活性剂和热稳定剂的作用及其选择方法。     

Vibration and pulsation processes in feed systems of liquid rocket engines

Pulsation and vibration process in high speed centrifugal pumps and feed lines were investigated. Linear and quadratic relations between pulsation parameters and main factors were obtained. The investigation of turbopump low frequency oscillations showed that the intensity of pulsations is proportional to the pump specific linear size. Linear mathematic models with lumped parameters fairly well demonstrate the vibration influence on low frequency flow pressure vibrations in pumps and feed lines. It is shown that, in some conditions, the pressure oscillation amplitude distribution by the vibrating feed lines length may be characterized by the presence of a node in an intermediate section. A one-dimensional mathematic model based on wave equations proved to be suitable for calculations of vibration and pulsation parameters within a wide frequency range.     

Changes in organ perfusion and weight ratios in post-simulated microgravity recovery

Head-down tilt models have been used as ground-based simulations of microgravity. Our previous animal research has demonstrated that there are significant changes in fluid distribution within 2 h after placement in a 45 degrees head-down tilt (45HDT) position and these changes in fluid distribution were still present after 14 days of 45HDT. Consequently, we investigated changes in fluid distribution during recovery from 16 days of 45HDT. Changes in radioactive tracer distribution and organ/body weight ratio were examined in rats randomly assigned to a 45HDT or prone control group. The 45HDT rats were suspended for 16 days and then allowed to recover at the prone position 0, 77, 101, or 125 h post-suspension. Animals were injected with technetium-labeled diethylenetriamine pentaacetate (99mTcDTPA, MW=492 amu, physical half-life of 6.02 h) and then killed 30 min post-injection. Lungs, heart, liver, spleen, kidneys, and brain were harvested, weighed, and measured for radioactive counts. Statistical analyses included two-way analysis of variance (ANOVA) that compared 45HDT versus controls at the four experimental time points. The organ weight divided by the body weight ratio for the brain, heart, kidneys and liver in the 45HDT rats was significantly different than the control rats, regardless of time (treatment). There was no difference between the different time points (time). The average 99mTcDTPA count divided by the organ weight ratio values for the heart, liver, and spleen were significantly higher in the 45HDT group than the control group. The average counts for the heart and spleen were significantly higher at 77, 101, and 125 h than at time zero. We conclude that the major organs have different recovery patterns after 45HDT for 16 days in the rat.     

燃气蒸汽式发射系统内弹道若干问题研究

通过对燃气蒸汽式发射动力系统的研究，总结出影响内弹道计算精度的若干因素，并就其中几个影响较大的问题进行了详细的分析，开发研制出了一套用于预估内弹道性能的系统化程序。通过实验数据的比较，验证了适用于内弹道计算的数学物理模型，为燃气蒸汽式发射系统设计提供参考依据。     

Future investigations onboard Soviet biosatellites of the Cosmos series.

Many rat experiments onboard Cosmos biosatellites have furnished information concerning the effects of weightlessness, artificial gravity, and ionizing radiation combined with weightlessness on structural and biochemical parameters of the animal body. The necessity to expand the scope of physiological investigations has led to the project of flight primate studies. It is planned to carry out the first primate experiments onboard the Cosmos biosatellite in 1982. At present investigations of weightlessness effects on the cardiovascular and vestibular systems, higher nervous activity, skeletal muscles and biorhythms of two rhesus monkeys are being developed and tested. It is also planned to conduct a study of weightlessness effects on embryogenesis of rats and bioenergetics of living systems onboard the same biosatellite. Further experiments onboard Cosmos biosatellites are planned.     

The cost benefits of the Spacelab system to scientific investigations and space applications

In the past, one of the major problems in performing scientific investigations in space has been the high cost of developing, integrating, and transporting scientific experiments into space. The limited resources of unmanned spacecraft, coupled with the requirements for completely automated operations, was another factor contributing to the high costs of scientific research in space. In previous space missions after developing, integrating and transporting costly experiments into space and obtaining successful data, the experiment facility and spacecraft have been lost forever, because they could not be returned to earth. The objective of this paper is to present how the utilization of the Spacelab System will result in cost benefits to the scientific community, and significantly reduce the cost of space operations from previous space programs.The following approach was used to quantify the cost benefits of using the Spacelab System to greatly reduce the operational costs of scientific research in space. An analysis was made of the series of activities required to combine individual scientific experiments into an integrated payload that is compatible with the Space Transportation System (STS). These activities, including Shuttle and Spacelab integration, communications and data processing, launch support requirements, and flight operations were analyzed to indicate how this new space system, when compared with previous space systems, will reduce the cost of space research. It will be shown that utilization of the Spacelab modular design, standard payload interfaces, optional Mission Dependent Equipment (MDE), and standard services, such as the Experiment Computer Operating System (ECOS), allow the user many more services than previous programs, at significantly lower costs. In addition, the missions will also be analyzed to relate their cost benefit contributions to space scientific research.The analytical tools that are being developed at MSFC in the form of computer programs that can rapidly analyze experiment to Spacelab interfaces will be discussed to show how these tools allow the Spacelab integrator to economically establish the payload compatibility of a Spacelab mission.The information used in this paper has been assimilated from the actual experience gained in integrating over 50 highly complex, scientific experiments that will fly on the Spacelab first and second missions. In addition, this paper described the work being done at the Marshall Space Flight Center (MSFC) to define the analytical integration tools and techniques required to economically and efficiently integrate a wide variety of Spacelab payloads and missions. The conclusions reached in this study are based on the actual experience gained at MSFC in its roles of Spacelab integration and mission managers for the first three Spacelab missions. The results of this paper will clearly show that the cost benefits of the Spacelab system will greatly reduce the costs and increase the opportunities for scientific investigation from space.     

Diuretic as a means for rapid adaptation to weightlessness

In a number of flights, cosmonauts and astronauts have experienced aggravation of their health status and general condition in the initial hours and days in a weightless environment. One of the trigger mechanisms for the onset of these unfavourable conditions at the start of space flight is a redistribution of body fluids and a blood shift towards the head. To ensure controlled hypohydration as a countermeasure to the deleterious effects of 0-g and to investigate the feasibility to control adaptation, six cosmonauts were administered lasix once a day during the first 3 days of a mission. All data of the experiment (correction test, questionnaire, hematocrit) were recorded on a special form in the logbook and transmitted to the control centre for processing. Results showed that the diuretic weakened the sensation of discomfort and improved the cosmonauts' general condition. Objective indices of the correction test indicate an increased work ability of cosmonauts. After hypohydration, circulating plasma volumes in the group were reduced by 6.8 + 1.0% on average.     

The effect of small vibrations on Marangoni convection and the free surface of a liquid bridge

The effects of small vibrations on Marangoni convection were investigated experimentally using a liquid bridge of 5 cSt silicone oil with a disk diameter of 7.0 mm, and an aspect ratio close to 0.5. Experiments were performed to determine the critical temperature difference data for no vibration case and with small vibrations applied. The experimental results have shown that the effect of small vibrations on the onset of oscillatory flow is small since the critical temperature difference data for different aspect ratios were not affected by the vibrations. To clarify the surface oscillation phenomena induced by external vibrations, a 3-D numerical simulation model was also developed using a level set algorithm to predict the surface oscillations of isothermal silicone oil bridges. By subjecting the liquid bridge to small vibrations, the surface oscillation characteristics were predicted numerically, and the numerical results compared well with the predictions of an analytical model proposed previously. Furthermore, the effect of small vibrations on the surface vibration amplitude of the liquid bridge is also discussed.