A new method of determining the spectral index for protons in the energy range about 10<Superscript>13</Superscript> eV

We consider a relationship between the difference in spectral indices of the spectra of single hadrons and all hadrons (_sngl – _h) and the difference in the indices of the spectra of galactic cosmic ray (GCR) protons and nuclei. It is demonstrated that at the mountain level the ratio (_p – _Z)/(_sngl – _h) is always larger than unity, if (_sngl – _h) > 0.1. From the experimental value _sngl – _h = 0.4 ± 0.05 we derive that, in the vicinity of E = 10 TeV, _p – _Z 0.49 ± 0.06 , i.e., _p 3.09 ± 0.06.__________Translated from Kosmicheskie Issledovaniya, Vol. 43, No. 2, 2005, pp. 83–87.Original Russian Text Copyright © 2005 by Grigorov, Tolstaya.     

Exercise response to simulated weightlessness

Two bed rest analog studies of space flight were performed; one 14 d and the other 28 d in duration. Exercise response was studied in detail during the 28 d study and following both the 14 d and 28 d studies. This paper relates the results of these studies to physiologic changes noted during and following space flight. The most consistent change noted after both bed rest and space flight is an elevated heart rate during exercise. A second consistent finding is a postflight or postbed rest reduction in cardiac stroke volume. Cardiac output changes were variable. The inability to simulate inflight activity levels and personal exercise makes a direct comparison between bed rest and the results from specific space flights difficult.     

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.     

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.     

Loading effects on rat craniomandibular morphology: a system for gravity studies

Gravity effects on muscle and bone are a major impediment to long-term space travel. We introduce a model for studying these effects, the craniomandibular system. Some advantages of this system include: (1) craniomandibular morphology is determined by epigenetic factors including gravity, (2) relatively light forces can significantly alter its morphology, and (3) soft diet and tooth loss produce effects that are similar to those produced in lower limbs by weightlessness. In the study, implants made either of gold (experimental group) or lightweight acrylic (controls) were attached to adult rats' mandibles. After 13 weeks, the animals' skulls and mandibles were dissected. Pair-wise comparisons indicated that the experimental animals showed significantly shortened and narrowed cranial bases, and significant changes in the posterior zygomatic arch region. These results indicate that simulated macrogravity influences bone remodeling in the adult craniomandibular system.     

Choroidal responses in microgravity. (SLS-1, SLS-2 and hindlimb-suspension experiments)

Fluid and electrolyte shifts occuring during human spaceflight have been reported and investigated at the level of blood, cardio-vascular and renal responses. Very few data were available concerning the cerebral fluid and electrolyte adaptation to microgravity, even in animal models. It is the reason why we developed several studies focused on the effects of spaceflight (SLS-1 and SLS-2 programs, carried on NASA STS 40 and 56 missions, which were 9- and 14-day flights, respectively), on structural and functional features of choroid plexuses, organs which secrete 70–90 % of cerebrospinal fluid (CSF) and which are involved in brain homeostasis. Rats flown aboard space shuttles were sacrificed either in space (SLS-2 experiment, on flight day 13) or 4–8 hours after landing (SLS-1 and SLS-2 experiments). Quantitative autoradiography performed by microdensitometry and image analysis, showed that lateral and third ventricle choroid plexuses from rats flown for SLS-1 experiment demonstrated an increased number (about x 2) of binding sites to natriuretic peptides (which are known to be involved in mechanisms regulating CSF production). Using electron microscopy and immunocytochemistry, we studied the cellular response of choroid plexuses, which produce cerebrospinal fluid (CSF) in brain lateral, third and fourth ventricles. We demonstrated that spaceflight (SLS-2 experiment, inflight samples) induces changes in the choroidal cell structure (apical microvilli, kinocilia organization, vesicle accumulation) and protein distribution or expression (carbonic anhydrase II, water channels,…). These observations suggested a loss of choroidal cell polarity and a decrease in CSF secretion. Hindlimb-suspended rats displayed similar choroidal changes. All together, these results support the hypothesis of a modified CSF production in rats during long-term (9, 13 or 14 days) adaptations to microgravity.     

Changes in chromatin and nucleic acids in rat tissues after two-week spaceflight

The quantitative changes in nucleic acids and chromatin breakdown were followed in blood, thymus and spleen in rats after 14 day flights on board the biosatellites Cosmos-1887 and Cosmos-2044. Quantitative nucleic acid changes within 8-11 h after landing were only mild, most statistically non-significant. An analysis at 48 h after landing showed a marked decrease in a total content of DNA and RNA in spleen and thymus. Within 8-11 h after landing, the symptoms of chromatin breakdown were found as is seen in an increased concentration of its fragments-polydeoxyribonucleotides. The obtained results show that a partial adaptation to microgravity occurs up to flight day 14 in lymphoid organs. Adaptation is accompanied with a reappearing of the sensitive cells. Their chromatin breaks down, then, in a final phase of flight due to hypergravity stress manifesting itself by a temporary increase in polydeoxyribonucleotide concentration several hours after landing. The results are discussed in relation to the changes in chosen parameters after shorter or more prolonged flights.     

Working and walking on small asteroids with circumferential ropes

The low gravity of a small asteroid would present a challenge for an astronaut attempting to work on its surface. Extravehicular activities (EVAs) of the sophistication of the Apollo Moon missions are not likely to be possible if astronauts attempt to walk freely on the asteroid, hover above its surface, or anchor locally into the regolith. Manipulating large rocks, drilling, and excavating at multiple locations is a high priority science objective, but would be difficult without a hold-down mechanism. If the asteroid has even a small rotation rate, maneuvering precisely over its surface could be cumbersome. A plausible means of conducting complex EVAs is to tie ropes entirely around the asteroid, under which the astronaut is pushed downward onto the asteroid surface by the tension in the rope. The downward force provides an artificial gravity that permits the astronaut to drill, excavate, hammer, and carefully document materials on the surface without the worry of being thrown from the asteroid. An astronaut could also use the ropes as handholds or guides to maneuver freely over the surface.     

On the Origin of High-Latitude Boundary Layer of the Earth's Magnetosphere

Localization of the reconnection region at the dayside magnetopause is among the unsolved problems of magnetospheric physics. There are two alternative models, one of which predicts the reconnection at the equatorial magnetopause, and the other predicts the reconnection in the region where the magnetic field of the solar wind flowing around the magnetosphere is antiparallel to the geomagnetic field. The statistical analysis carried out for 53 INTERBALL-1crossings of the high-latitude magnetopause in a special coordinate frame invariant with respect to the interplanetary conditions shows that the model of a reconnection in antiparallel fields agrees well with the experimental data.