Long-duration Flight Research Articles

Effects of Age, Sex, and Reproductive Status on Flight by the Tarnished Plant Bug (Heteroptera: Miridae)

We determined the frequency and duration of flight by tarnished plant bugs, Lygus lineolaris (Palisot de Beauvais), on flight mills. An average maximum speed of 0.45 m/s (≍1.6 km/h) was observed during sustained flights. Bugs of prereproductive (< d old) age flew much less than older individuals. Females made more long-duration flights and flew longer than did males. Mating status had no effect on flight activity, but females with chorionated eggs flew more than females without eggs. The single-flight durations of young, parous females were longest. This information supports studies showing that early-reproductive females were more likely to colonize new habitat patches than were males or prereproductive females.

Evolution of the NASA long-duration balloon program

The development of long-duration ballooning techniques to support flights of 1–2 ton payloads for periods up to 2 weeks, possibly even longer, offers a near-space scientific mission capability with an order of magnitude improvement over traditional balloon flights. This revolution in scientific research ballooning began with the solution of the manufacturing difficulties that plagued the program in the first half of the 1980's, and it has culminated in the early 1990's with three successive circumnavigations of the Antartic continent in 9 to 14 day flights. A complementary capability in the Northern hemisphere, which would approximately double the number of flights that could supported each year, is needed to accommodate the trend for conventional payloads to be modified, or developed, for long-duration flights. Plans are already underway to employ the order-of-magnitude increased flight time for support of multi-flight research programs that will produce results comparable to some space missions. An overview of the current status and near-term plans for ballooning will be presented, along with a discussion of some major science initiatives that have been enabled.

Space flight and the immune system

Depression of lymphocyte response to mitogens in cosmonauts after space flight was reported for the first time in the early 1970s by Soviet immunologists. Today we know that depression of lymphocyte function affects at least 50% of space crew members. Investigations on the ground on subjects undergoing physical and psychological stress indicate that stress is a major factor in immune depression of astronauts. This is despite the fact that weightlessness per se has a strong inhibitory effect on lymphocyte activation in vitro. Although the changes observed never harmed the health of astronauts, immunological changes must be seriously investigated and understood in view of long-duration flights on space stations in an Earth orbit, to other planets such as Mars and to the Moon.

Concept for an open-neck stratospheric balloon with long-duration flight capability

The CNES Balloon Division recently designed a new type of open-neck stratospheric balloon with a long-duration flight capability. The main feature of this new concept is that it ensures a stable flight level under all conditions, during day and night, without the need to release ballast. The approach adopted is to cover the top of the balloon envelope with an insulating “cape” corresponding to 3% of the total envelope area under daytime conditions. As the balloon descends after sunset, its volume decreases while the proportion of the gas bubble (i.e. the part of the envelope in direct contact with the inflation gas) covered by the cape increases to 50%. Even under the most adverse radiative conditions, this configuration produces a sufficient improvement in the balloon's heat budget to ensure a stable float altitude in the lower stratosphere. As soon as the sun rises, the balloon ascends to its daytime float altitude, making it possible to repeat a large number of day-night cycles. If one assumes that flight duration is limited only by gas diffusion through the envelope, this type of balloon should be able to remain aloft for up to three weeks.

Chapter 2 Soviet Psychophysiological Investigations Of Simulated Isolation: Some Results And Prospects

This chapter focuses on the investigations of simulated isolation. During the past 30 years, many experiments on simulated isolation were carried out. These experiments can be classified as follows: (1) severe isolation without contacts with the outer world; (2) isolation with limited communication with the outer world; (3) isolation combined with work. In most of these experiments isolation was combined with changes in worklrest schedule, environmental pa- rameters (humidity, temperature, atmospheric pressure, and noise level), the breathing of unusual gas mixtures, the influence of simulated microgravity, and specially organized accidents. Soviet psychologists have devised a psychological support system to help cosmonauts overcome the negative psychological effects of long-duration flight through active rest facilities, contemplative psychic active, and the promotion of self realization. Recommendations for further investigations are also provided in the chapter. Prolonged mild isolation disturbs the psychological state of a subject and reduces his/her work capability; the direction and extent of these changes depend upon motivation and will to withstand difficult conditions of the subject and the time of onset of these symptoms depends upon the psychological stance of the subject. Psychological support methods can reduce the effects of isolation.

Effect of exercise and bisphosphonate on mineral balance and bone density during 360 day antiorthostatic hypokinesia.

As we enter a phase of space exploration that will involve long-duration flights, there is a need to use ground-based models to study the long-term effects of countermeasures to prevent the loss of bone mineral in microgravity. Mineral balances, hormone levels, and bone density were measured for 360 days in nine bed rest subjects treated with an exercise program used by cosmonauts. Four of these subjects received the bisphosphonate, ethane-1-hydroxy-1-disphosphonate, 900 mg daily, a drug known to inhibit bone resorption. Compared to a 120 day control period, the bisphosphonate combined with exercise reduced negative calcium balances by 50% for the first 120 days, 80% for the second 120 days, and 69% during the third 120 days. Exercise alone had no effect until the second 120 day period, when calcium balance improved 52%. Negative phosphorus balances were not affected by either treatment. Magnesium balances were negative during the first 120 days and returned to nearly normal during the last 240 days in both groups. The combined exercise and bisphosphonate treatment prevented increases in serum ionized calcium and decreases in plasma calcitonin during the first 120 days, as well as trends toward decreases in the mineral density of the femoral neck. These results suggest that bisphosphonates can be efficiently used together with exercise to reduce calcium loss and prevent some of the changes in mineral metabolism during long-term simulated microgravity.

Reproductive Maturity, Mating Status, and Long-Duration Flight Behavior of Agrotis ipsilon (Lepidoptera: Noctuidae) and the Conceptual Misuse of the Oogenesis'Flight Syndrome by Entomologists

The relationship between long-duration flight and the state of oogenesis in the migratory moth Agrotis ipsilon (Hufnagel) was examined in unmated females 1,2,3,4, and 5 d old by using computer-interfaced flight mills. Evidence presented suggests that such long-duration flights (i.e., continuous flights ≥1 h) are indices of migratory flight. There were no significant correlations between the number of chorionated eggs and flight duration, times of flight initiation and termination, or flight speed within age classes 1–4. In 5-d-old moths, however, there was a positive correlation with flight duration. Mated females began their long-duration flights ≍3 h later in the night and averaged 2 h of flight less than unmated females. Their propensity and capacity to engage in such flights, however, was still considerable. The long-duration flight behavior of 3-d-old mated males was similar to that of unmated males, as was their propensity to engage in such flights. Therefore, a delay in oogenesis and suppression of reproductive behavior are not prerequisites for the initiation of long-duration flight activity in A. ipsilon , as would be predicted if the oogenesis-flight syndrome was characteristic of this species. Our data are consistent with previous findings that suggest that most females arrive in the midwestern United States in the spring already mated. We argue that the concept of an oogenesis-flight syndrome in migratory insects has no inherent explanatory power and its only valid use is as a convenient descriptive term. Its most frequent misuse as an explanatory principle is seen in the common assumption that duration of the prereproductive period determines the maximum duration of the migratory period. Empirical evidence as well as theoretical considerations indicate that it is never safe to accept this assumption without testing. To do so risks impeding progress in understanding specific systems through unwarranted extrapolation of data or through building a house of cards.

Lack of Translation of Density-Induced Morphological Polyphenism to Long-Duration Flight Behavior of Black Cutworm (Lepidoptera: Noctuidae)

Larvae of black cutworm, Agrotis ipsilon (Hufnagel), reared under crowded conditions in the laboratory were darker and developed more slowly than larvae reared singly. Crowding reduced the length and weight of pupae, and the adults were correspondingly smaller than those from uncrowded populations. Rate of reproductive maturation of females was not influenced by larval density. Crowding had no significant effect on the crawling behavior of sixth instars and very little effect on the flight behavior of adults tethered to flight mills. No evidence that crowding leads to a distinct migratory phase or even to an increased propensity to initiate long-duration flight was found. To the contrary, the data suggest that moths from crowded populations may suffer a loss in migratory capacity because of their smaller size (and presumably smaller stores of flight fuel) and lower wing area:body size ratios, which may make flight energetically more expensive.

Microdialysis crystallization chamber: Design of a solvent exchangeable microsialysis crystallization system for manual or automatic control of protein crystal growth at microgravity

Several microdialysis crystallizing chambers (MDCC) are being developed to be used in microgravity (μG) situations where crystallization experiments could be performed on unmanned space flights of long duration. Disturbance of the crystal during growth and during recovery is to kept to a minimum.

Effects of a 1-wk spaceflight on morphological and mechanical properties of growing bone.

The morphological and mechanical responses of tibia and humerus were assessed in growing male rats after a 1-wk spaceflight aboard NASA Spacelab 3. In contrast to flights of longer duration, changes in middiaphysial cross-sectional morphology were minimal. Inhibition of longitudinal growth was not found in the tibia but was apparent in the humerus. The normal age-related increase in tibial middiaphysial density was not observed in the flight animals. Three-point bending tests indicated that a 1-wk spaceflight impeded the maturation of bone strength and stiffness, with the effects more pronounced in the tibia than in the humerus. Material property alterations in bone thus overshadowed morphological factors in determining the bone's mechanical response. It is likely that deprivation of normal weight-bearing loads was a major factor contributing to the observed changes, but endocrine and other local factors must also be considered.

Summary of medical investigations in the U.S.S.R. manned space missions

The results of biomedical investigations carried out in the U.S.S.R. manned space missions are discussed. Their basic result is well-documented evidence that man can perform space flights of long duration. The investigations have demonstrated no direct correlation between inflight or postflight physiological reactions of crewmembers and flight duration. In all likelihood, this can be attributed to the fact that special exercises done inflight efficiently prevented adverse effects of weightlessness. However, human reactions to weightlessness need further study. They include negative calcium balance and anemia as well as vestibulo-autonomic disorders shown by crewmembers at early stages of weightlessness. Attention should be given to psychological, social-psychological and ethical problems that may also limit further increase in flight duration.

Tracking and communication in long-duration flights

Balloon location techniques have developed along the same lines as ship and aircraft navigation systems. Early NCAR balloon flights were located by sun angle measurements versus time and magnetic field measurement, much the same way that Captain Cook used to navigate his sailing vessel. Others have used radio systems developed for ship and aircraft location such as Omega, Loran, radio direction finding, Variable Omnidirectional Radio (VOR) and radar transponders.

Superpressure Balloon Flights in the Tropical Boundary Layer

Abstract Two series of quasi-constant-level pressurized balloons have been flown within the tropical planetary boundary layer, preliminary to a larger experiment for exploring the low-level flow over the Indian Ocean. The first flight series from a South Pacific island indicated a very short life expectancy of the equipment due to the high probability of the vehicle being overloaded by rain drops or dew and the catastrophic effect of immersion. A second series of flights from Ascension Island in the South Atlantic was performed to test a new and completely self-enclosed balloon design, as well as a metalized reflecting screen for radiative control of the envelope temperature. This new design demonstrated acceptable vertical stability, thus proving the feasibility of long-duration quasi-horizontal balloon flights at levels as low as 500 m above the sea surface.

Energy spectrum and flux of 3- to 20-Mev neutrons and 1- to 10-Mev gamma rays in the atmosphere

An experiment is described which was designed to measure the neutron and gamma ray energy spectrums and fluxes in the energy intervals 3 to 20 MeV and 1 to 10 MeV, respectively. In addition, from the 3 to 20-MeV proton recoil spectrums it is possible to infer the shape of the neutron energy spectrum from 20 to 50 MeV. The detecting system utilized a separate charged particle rejection scheme and a two-parameter display system for the output from the pulse shape discrimination which separated gamma rays from neutrons (n). Two long-duration flights were made with this detector in 1970 at Palestine, Tex. (P sub c = 4.6 Gv) and at Ft. Churchill, Canada (P sub c = 0.3 Gv).

Studies on Natural Populations of Oncopeltus fasciatus (Dallas), the Large Milkweed Bug

Oncopeltus fasciatus (Dallas) was studied in stands of Asclepias syriaca L., the common milkweed, in central Missouri and Illinois. Rate of appearance of adults in early summer and disappearance in fall as well as times of peak mating activity, peak numbers, and relative mobility were followed. Relationships of field behavior to laboratory results on the effects of photoperiod and temperature on longduration flights, copulation, and oviposition were made. Eggs and colonies of first and second instars reached peak numbers during late August. Host plants chosen for oviposition were taller, had more pods than average, and were in areas of greater than average density of A syriaca. Most eggs were deposited when the minimum daily field temperature was above the threshold temperature for hatching. Use of experimental ovipositional forms by females in the laboratory coincided with observed preferences in the field. Maturation through the third and fourth instars culminated in peak numbers of fifth instars in the first half of September and adults in the last half of September. The average nymphal life length was 40 days and survival to the adult stage was 23.1%. The mean number of 0. fasciatus per milkweed was 14.9 which was below the density where effects of crowding were found in laboratory populations. Ninety per cent of 0. fasciatus occurred in aggregations and 70% were in groups of 3-30 per host plant. Individuals found alone or in pairs were generally adults. Correlation of the total number of 0. fasciatus to the number of aggregations was positively significant (0.01 level) but only 4.4% of the total number of A. syriaca and 16% of the total pods were utilized. INTRODUCTION Oncopeltus fasciatus (Dallas) is widespread in the Nearctic and feeds on numerous species of the milkweed family, Asclepiadaceae. Although 0. fasciatus does not seem to use its collected cardenolides as a defense against predation (Duffey, 1970), host specificity has been clearly shown (Beck, Edwards, and Medler, 1958; Bongers, 1969a; Feir and Suen, 1971). 0. fasciatus has evolved not only to feed on this single family of plants but also to ingest and store large amounts of digitalis-like compounds which are found in these plants (Feir and Suen, 1971). Large milkweed bugs are raised in laboratories and used extensively in invertebrate physiological and developmental experimentation, but little is known of the parameters of natural populations of these insects. Recent investigations have revealed changes of behavior patterns of fifth nymphal instars, e.g., reactions to food, humidity, light, temperature, and gravity (Barrett and Chiang, 1967) and the cyclic behaviors of adults, e.g., feeding, mating, oviposition, and flight (Dingle, 1966; 1968a, 1968b). But if any of these experimental laboratory results are to be related to species survival of 0. fasciatus, as eventually they must be, extensive information should be available on

Standards for Noise Levels in Cabins of Spacecraft During Long-Duration Flights

Standards for Noise Levels in Cabins of Spacecraft During Long-Duration Flights

Radiation effects in silicon solar cells

Abstract Silicon solar cells have been utilized as the principal source of electrical energy for space satellites during the past decade. Despite the reliability of these photovoltaic devices, degradation of their power output by charged particle radiation in the earth's geomagnetic field has continued to be the primary problem for their use on flights of long-duration. A study of radiation damage induced by 1 MeV electrons in a variety of current silicon solar cell types has been conducted as a function of dopant impurity and resistivity of the base region. A companion study of radiation damage induced by nominal 0.2 MeV protons was performed in solar cells with coverslips having small cell areas exposed alongside the coverslip. The photovoltaic current-voltage characteristics were measured under a solar simulator emitting 140mW/cm2 at air mass zero. Irradiations were performed at room temperature to fluences of 1 × 1015 e/cm2 and 1 × 1015 p/cm2. The efficiency of 10 ohm-cm cells after large fluences was superior to cells of 2 ohm-cm base resistivity. No significant differences were observed between boron- and aluminum-doped cells. Solar cell exposure to low energy Protons resulted in an 8 per cent loss in power at a fluence of 1 × 1014 p/cm2 when as little as 2 per cent of the solar cell surface was left unshielded.

Space Medicine in Perspective

The second flight series of the US Manned Space Flight Program has just been concluded. The successful and safely conducted Mercury and Gemini programs have provided us with the first significant knowledge concerning man's capability to cope with the environment of space. We are eagerly looking forward to long-duration flights in the three-man Apollo series and the use of a space laboratory to be accomplished in the S-IVB orbital workshop. It seems timely to review our medical progress and knowledge concerning space medicine and to evaluate the course on which we are embarked. Nineteen men have flown 25 manned flights, giving us a total weightless experience of some 2,000 man-hours. Three individuals have flown both single- and dual-crew spacecraft and four individuals have flown twice in the Gemini spacecraft. Summaries of these flight programs are presented in Tables 1 and 2. This massive flight experience, while literally only scratching the

Photographic Techniques for Project Mercury Ground Range Evaluation

The NASA Project Mercury spacecraft is tracked through its launch, orbit, and recovery phases by a world-wide network of tracking stations. The short duration of the manned flights and the paramount considerations of the astronaut's safety require a much more sophisticated ground range than is needed for unmanned flights of longer duration. Thorough testing of the ground acquisition and radar tracking equipment, prior to the spacecraft flights, was accomplished economically with boresight camera techniques, using DC-3 and C-54 aircraft specially equipped to simulate an orbiting spacecraft. Development of this test program is described, along with a discussion of the photographic equipment employed, the problems and limitations encountered and the aircraft equipment.