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At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1994

Report of the Task Force on the Shuttle-Mir Rendezvous and Docking Missions

In October 1992, Russia and the U.S. agreed to conduct a fundamentally new program of human cooperation in space. This original 'Shuttle-Mir' project encompassed combined astronaut-cosmonaut activities on the Shuttle, Soyuz, and Mir spacecraft. At that time, the project was limited to: the STS-60 Shuttle mission, which was completed in February 1994 and carried the first Russian cosmonaut; the planned March 1995 Soyuz 18 launch which will carry a U.S. astronaut to the Mir space station for a three month mission; and the STS-71 Shuttle mission which is scheduled to rendezvous and dock with the Mir space station in June 1995. The Task Force's specific recommendations are given.

Source record↗
NASA NTRS2002

Alterations in protein metabolism during space flight and inactivity

Space flight and the accompanying diminished muscular activity lead to a loss of body nitrogen and muscle function. These losses may affect crew capabilities and health in long-duration missions. Space flight alters protein metabolism such that the body is unable to maintain protein synthetic rates. A concomitant hypocaloric intake and altered anabolic/catabolic hormonal profiles may contribute to or exacerbate this problem. The inactivity associated with bedrest also reduces muscle and whole-body protein synthesis. For this reason, bedrest provides a good model for the investigation of potential exercise and nutritional countermeasures to restore muscle protein synthesis. We have demonstrated that minimal resistance exercise preserves muscle protein synthesis throughout bedrest. In addition, ongoing work indicates that an essential amino acid and carbohydrate supplement may ameliorate the loss of lean body mass and muscle strength associated with 28 d of bedrest. The investigation of inactivity-induced alterations in protein metabolism, during space flight or prolonged bedrest, is applicable to clinical populations and, in a more general sense, to the problems associated with the decreased activity that occur with aging.

Non-NASA Center↗
NASA NTRS2002

Body mass, energy intake, and water consumption of rats and humans during space flight

Alteration of metabolism has been suggested as a major limiting factor to long-term space flight. In humans and primates, a negative energy balance has been reported. The metabolic response of rats to space flight has been suggested to result in a negative energy balance. We hypothesized that rats flown in space would maintain energy balance as indicated by maintenance of caloric intake and body mass gain. Further, the metabolism of the rat would be similar to that of laboratory-reared animals. We studied the results from 15 space flights lasting 4 to 19 d. There was no difference in average body weight (206 +/- 13.9 versus 206 +/- 14.8 g), body weight gain (5.8 +/- 0.48 versus 5.9 +/- 0.56 g/d), caloric intake (309 +/- 21.0 versus 309 +/- 20.1 kcal/kg of body mass per day), or water intake (200 +/- 8.6 versus 199 +/- 9.3 mL/kg of body mass per day) between flight and ground control animals. Compared with standard laboratory animals of similar body mass, no differences were noted. The observations suggested that the negative balance observed in humans and non-human primates may be due to other factors in the space-flight environment.

Non-NASA Center↗
NASA NTRS2002

Comparison of echocardiographic changes after short- and long-duration spaceflight

BACKGROUND: Previous echocardiographic studies of astronauts before and after short-duration (4-17 d) missions have demonstrated a decrease in resting left ventricular stroke volume, but maintained ejection fraction (EF) and cardiac output. Similar studies before and after long-duration (129-144 d) spaceflight have been rare and their overall results equivocal. METHODS: Echocardiographic measurements (M-mode, 2-D, and Doppler) were obtained from short-duration (n = 13) and long-duration (n = 4) crewmembers to evaluate cardiac chamber sizes and function. RESULTS: Compared with short-duration astronauts, long-duration crewmembers had decreases in EF (+6+/-0.02 vs. -10.5+/-0.03%, p = 0.005) and percent fractional shortening (+7+/-0.03 vs. -11+/-0.07%, p = 0.015), and an increase in left ventricular end systolic volume (-12+/-0.06 vs. +39+/-0.24%, p = 0.011). CONCLUSIONS: These data suggest a reduction in cardiac function that relates to mission duration. As the changes in BP and circulating blood volume are reported to be similar after short- and long-duration flights, the smaller EF after longer spaceflights may be due to a decrease in cardiac function rather than altered blood volume.

short duration↗
NASA NTRS2000

Social and cultural issues during Shuttle/Mir space missions

A number of interpersonal issues relevant to manned space missions have been identified from the literature. These include crew tension, cohesion, leadership, language and cultural factors, and displacement. Ground-based studies by others and us have clarified some of the parameters of these issues and have indicated ways in which they could be studied during actual space missions. In this paper, we summarize some of our findings related to social and cultural issues from a NASA-funded study conducted during several Shuttle/Mir space missions. We used standardized mood and group climate measures that were completed on a weekly basis by American and Russian crew and mission control subjects who participated in these missions. Our results indicated that American subjects reported more dissatisfaction with their interpersonal environment than their Russian counterparts, especially American astronauts. Mission control personnel were more dysphoric than crewmembers, but both groups were significantly less dysphoric than other work groups on Earth. Countermeasures based on our findings are discussed which can be applied to future multicultural space missions. Published by Elsevier Science Ltd.

NASA Discipline Space Human Factors↗
NASA NTRS2001

Space radiation and cataracts in astronauts

For over 30 years, astronauts in Earth orbit or on missions to the moon have been exposed to space radiation comprised of high-energy protons and heavy ions and secondary particles produced in collisions with spacecraft and tissue. Large uncertainties exist in the projection of risks of late effects from space radiation such as cancer and cataracts due to the paucity [corrected] of epidemiological data. Here we present epidemiological [corrected] data linking an increased risk of cataracts for astronauts with higher lens doses (>8 mSv) of space radiation relative to other astronauts with lower lens doses (<8 mSv). Our study uses historical data for cataract incidence in the 295 astronauts participating in NASA's Longitudinal Study of Astronaut Health (LSAH) and individual occupational radiation exposure data. These results, while preliminary because of the use of subjective scoring methods, suggest that relatively low doses of space radiation may predispose crew to [corrected] an increased incidence and early appearance of cataracts.

NASA Center JSC↗
NASA NTRS1998

The effect of space missions on gravity-responsive torsional eye movements

Three astronauts underwent preflight, inflight, and postflight testing of spontaneous ocular torsion and of ocular counterrolling (OCR), reflexes governed by the gravity-responsive otolith organs in the inner ear. One astronaut, A, had a 30-day space mission on Euromir '94 and was examined monocularly with SensoMotoric Instruments video-oculography (VOG). The other two astronauts, B and C, were studied with a binocular VOG and flew an 180-day mission on Euromir '95. In space, spontaneous eye torsion in the upright position was found to be substantially offset from baseline Earth-based recordings in all three subjects for the duration of the flights. In addition, the binocular studies showed a marked torsional disconjugacy. On return to Earth, offset and torsional disconjugacy persisted for many days. OCR in response to 30 degrees right and left tilt was examined preflight and postflight. Compared to preflight, Astronaut A showed reduced OCR immediately postflight, which increased over the next few days. Both Astronauts B and C had increased OCR postflight, which gradually approached but did not achieve the preflight values over 13 days postflight. The adaptation of ocular torsion in space in one astronaut and not in the other two, and slow adaptation postflight, may reflect the lack of visual feed-back and the open loop nature of the otolith-ocular torsion reflex.

short duration↗
NASA NTRS1997

Changes in the immune system during and after spaceflight

The results of immunological analyses before, during and after spaceflight, have established the fact that spaceflight can result in a blunting of the immune mechanisms of human crew members and animal test species. There is some evidence that the immune function changes in short-term flights resemble those occurring after acute stress, while the changes during long-term flights resemble those caused by chronic stress. In addition, this blunting of the immune function occurs concomitant with a relative increase in potentially infectious microorganisms in the space cabin environment. This combination of events results in an increased probability of inflight infectious events. The realization of this probability has been shown to be partially negated by the judicious use of a preflight health stabilization program and other operational countermeasures. The continuation of these countermeasures, as well as microbial and immunological monitoring, are recommended for continued spaceflight safety.

manned↗
NASA NTRS2005

Exercise and pharmacological countermeasures for bone loss during long-duration space flight

Bone loss in the lower extremities and lumbar spine is an established consequence of long-duration human space flight. Astronauts typically lose as much bone mass in the proximal femur in 1 month as postmenopausal women on Earth lose in 1 year. Pharmacological interventions have not been routinely used in space, and countermeasure programs have depended solely upon exercise. However, it is clear that the osteogenic stimulus from exercise has been inadequate to maintain bone mass, due to insufficient load or duration. Attention has therefore been focused on several pharmacological interventions that have been successful in preventing or attenuating osteoporosis on Earth. Anti-resorptives are the class of drugs most commonly used to treat osteoporosis in postmenopausal women, notably alendronate sodium, risedronate sodium, zoledronic acid, and selective estrogen receptor modulators, such as raloxifene. There has also been considerable recent interest in anabolic agents such as parathyroid hormone (PTH) and teriparatide (rhPTH [1-34]). Vitamin D and calcium supplementation have also been used. Recent studies of kindreds with abnormally high bone mineral density have provided insight into the genetic regulation of bone mass. This has led to potential therapeutic interventions based on the LRP5, Wnt and BMP2 pathways. Another target is the RANK-L/osteoprotegerin signaling pathway, which influences bone turnover by regulating osteoclast formation and maturation. Trials using such therapies in space are being planned. Among the factors to be considered are dose-response relationships, bone quality, post-use recovery, and combination therapies--all of which may have unique characteristics when the drugs are used in space.

NASA Discipline Musculoskeletal↗
NASA NTRS1996

Mir Cooperative Solar Array Project Accelerated Life Thermal Cycling Test

The Mir Cooperative Solar Array (MCSA) project was a joint U.S./Russian effort to build a photovoltaic (PV) solar array and deliver it to the Russian space station Mir. The MCSA will be used to increase the electrical power on Mir and provide PV array performance data in support of Phase 1 of the International Space Station. The MCSA was brought to Mir by space shuttle Atlantis in November 1995. This report describes an accelerated thermal life cycle test which was performed on two samples of the MCSA. In eight months time, two MCSA solar array 'mini' panel test articles were simultaneously put through 24,000 thermal cycles. There was no significant degradation in the structural integrity of the test articles and no electrical degradation, not including one cell damaged early and removed from consideration. The nature of the performance degradation caused by this one cell is briefly discussed. As a result of this test, changes were made to improve some aspects of the solar cell coupon-to-support frame interface on the flight unit. It was concluded from the results that the integration of the U.S. solar cell modules with the Russian support structure would be able to withstand at least 24,000 thermal cycles (4 years on-orbit). This was considered a successful development test.

Hoffman, David J.↗
NASA NTRS1997

Plant reproduction in spaceflight environments

Because plant reproduction is a complex developmental process there are many possible sites of perturbation by the unusual environments of orbital spacecraft. Previous long-duration experiments on Soviet platforms shared features of slowed development through the vegetative stage of plant growth and aborted reproductive function. Our goal has been to understand how special features of the spaceflight environment impact physiological function and reproductive development. In a series of short-duration experiments in the Shuttle mid-deck we studied early reproductive development in Arabidopsis thaliana. Pollen and ovule development aborted at an early stage in the first experiment on STS-54 which utilized closed plant growth chambers. Post-flight analysis suggested that the plants may have been carbon dioxide limited. Subsequent experiments utilized carbon dioxide enrichment (on STS-51) and cabin air flow-through with an air exchange system (on STS-68). Both modifications allowed pollen and ovule development to occur normally on orbit, and full reproductive development up to the stage of an immature seed occurred on STS-68. However, analysis of plant roots from these experiments demonstrated a limitation in rootzone aeration in the spaceflight material that was not mitigated by these procedures. In the future, additional resources (crew time, upgraded flight hardware, and special platforms) will invite more elaborate, long-duration experimentation. On the ISS, a variable speed centrifuge and upgraded plant habitats will permit detailed experiments on the role of gravity in shaping the plant micro-environment, and what influence this plays during reproduction.

Review, Tutorial↗
NASA NTRS2002

Models to study gravitational biology of Mammalian reproduction

Mammalian reproduction evolved within Earth's 1-g gravitational field. As we move closer to the reality of space habitation, there is growing scientific interest in how different gravitational states influence reproduction in mammals. Habitation of space and extended spaceflight missions require prolonged exposure to decreased gravity (hypogravity, i.e., weightlessness). Lift-off and re-entry of the spacecraft are associated with exposure to increased gravity (hypergravity). Existing data suggest that spaceflight is associated with a constellation of changes in reproductive physiology and function. However, limited spaceflight opportunities and confounding effects of various nongravitational factors associated with spaceflight (i.e., radiation, stress) have led to the development of ground-based models for studying the effects of altered gravity on biological systems. Human bed rest and rodent hindlimb unloading paradigms are used to study exposure to hypogravity. Centrifugation is used to study hypergravity. Here, we review the results of spaceflight and ground-based models of altered gravity on reproductive physiology. Studies utilizing ground-based models that simulate hyper- and hypogravity have produced reproductive results similar to those obtained from spaceflight and are contributing new information on biological responses across the gravity continuum, thereby confirming the appropriateness of these models for studying reproductive responses to altered gravity and the underlying mechanisms of these responses. Together, these unique tools are yielding new insights into the gravitational biology of reproduction in mammals.

Review, Tutorial↗
NASA NTRS2001

Evolution of telemedicine in the space program and earth applications

Remote monitoring of crew, spacecraft, and environmental health has always been an integral part of the National Aeronautics and Space Administration's (NASA's) operations. Crew safety and mission success face a number of challenges in outerspace, including physiological adaptations to microgravity, radiation exposure, extreme temperatures and vacuum, and psychosocial reactions to space flight. The NASA effort to monitor and maintain crew health, system performance, and environmental integrity in space flight is a sophisticated and coordinated program of telemedicine combining cutting-edge engineering with medical expertise. As missions have increased in complexity, NASA telemedicine capabilities have grown apace, underlying its role in the field. At the same time, the terrestrial validation of telemedicine technologies to bring healthcare to remote locations provides feedback, improvement, and enhancement of the space program. As NASA progresses in its space exploration program, astronauts will join missions lasting months, even years, that take them millions of miles from home. These long-duration missions necessitate further technological breakthroughs in tele-operations and autonomous technology. Earth-based monitoring will no longer be real-time, requiring telemedicine capabilities to advance with future explorers as they travel deeper into space. The International Space Station will serve as a testbed for the telemedicine technologies to enable future missions as well as improve the quality of healthcare delivery on Earth.

long duration↗
NASA NTRS2000

Research into the effects of astronaut motion on the spacecraft: a review

The paper reviews the research that has been undertaken to understand and quantify the disturbance effects of the astronaut's motion inside and outside the spacecraft on the vehicle's attitude and acceleratory environment. In early investigations, the dynamic interaction of astronauts, modeled as point masses, and the spacecraft, modelled as a rigid body, was analyzed. Through ground-based experiments and the modeling of astronaut-induced forces and moments as stochastic processes, it became possible to estimate the magnitude and energy content of the loads produced by the astronaut. The first experiment in space to measure the astronaut-induced disturbances was conducted on the Skylab orbital station. Loads generated while performing routine operations were measured on board the Space Shuttle in 1994 and on the space station Mir in 1996-1997. c 2001 Elsevier Science Ltd. All rights reserved.

Skylab Project↗
NASA NTRS2001

Mass spectrometry in the U.S. space program: past, present, and future

Recent years have witnessed significant progress on the miniaturization of mass spectrometers for a variety of field applications. This article describes the development and application of mass spectrometry (MS) instrumentation to support of goals of the U.S. space program. Its main focus is on the two most common space-related applications of MS: studying the composition of planetary atmospheres and monitoring air quality on manned space missions. Both sets of applications present special requirements in terms of analytical performance (sensitivity, selectivity, speed, etc.), logistical considerations (space, weight, and power requirements), and deployment in perhaps the harshest of all possible environments (space). The MS instruments deployed on the Pioneer Venus and Mars Viking Lander missions are reviewed for the purposes of illustrating the unique features of the sample introduction systems, mass analyzers, and vacuum systems, and for presenting their specifications which are impressive even by today's standards. The various approaches for monitoring volatile organic compounds (VOCs) in cabin atmospheres are also reviewed. In the past, ground-based GC/MS instruments have been used to identify and quantify VOCs in archival samples collected during the Mercury, Apollo, Skylab, Space Shuttle, and Mir missions. Some of the data from the more recent missions are provided to illustrate the composition data obtained and to underscore the need for instrumentation to perform such monitoring in situ. Lastly, the development of two emerging technologies, Direct Sampling Ion Trap Mass Spectrometry (DSITMS) and GC/Ion Mobility Spectrometry (GC/IMS), will be discussed to illustrate their potential utility for future missions. c 2001 American Society for Mass Spectrometry.

NASA Discipline Environmental Health↗
NASA NTRS1999

Extra dose due to extravehicular activity during the NASA4 mission measured by an on-board TLD system

A microprocessor-controlled on-board TLD system, 'Pille'96', was used during the NASA4 (1997) mission to monitor the cosmic radiation dose inside the Mir Space Station and to measure the extra dose to two astronauts in the course of their extravehicular activity (EVA). For the EVA dose measurements, CaSO4:Dy bulb dosemeters were located in specially designed pockets of the ORLAN spacesuits. During an EVA lasting 6 h, the dose ratio inside and outside Mir was measured. During the EVA, Mir crossed the South Atlantic Anomaly (SAA) three times. Taking into account the influence of these three crossings the mean EVA/internal dose rate ratio was 3.2. Internal dose mapping using CaSO4:Dy dosemeters gave mean dose rates ranging from 9.3 to 18.3 microGy h-1 at locations where the shielding effect was not the same. Evaluation results of the high temperature region of LiF dosemeters are given to estimate the mean LET.

NASA Experiment Number 9401704↗