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The goals of the Life Sciences Division of the Office of Space Sciences and Application are to ensure the health, well being and productivity of humans in space and to acquire fundamental scientific knowledge in space life sciences. With these goals in mind Space Station Freedom represents substantial opportunities and significant challenges to the Life Sciences Division. For the first time it will be possible to replicate experimental data from a variety of simultaneously exposed species with appropriate controls and real-time analytical capabilities over extended periods of time. At the same time, a system for monitoring and ameliorating the physiological adaptations that occur in humans subjected to extended space flight must be evolved to provide the continuing operational support to the SSF crew. To meet its goals, and take advantage of the opportunities and overcome the challenges presented by Space Station Freedom, the Life Sciences Division is developing a suite of discipline-focused sequence. The research phase of the Life Sciences Space Station Freedom Program will commence with the utilization flights following the deployment of the U.S. laboratory module and achievement of Man Tended Capability. Investigators that want the Life Sciences Division to sponsor their experiment on SSF can do so in one of three ways: submitting a proposal in response to a NASA Research Announcement (NRA), submitting a proposal in response to an Announcement of Opportunity (AO), or submitting an unsolicited proposal. The scientific merit of all proposals will be evaluated by peer review panels. Proposals will also be evaluated based on relevance to NASA's missions and on the results of an Engineering and Cost Analyses. The Life Sciences Division expects that the majority of its funding opportunities will be announced through NRA's. It is anticipated that the first NRA will be released approximately three years before first element launch (currently scheduled for late 1995). Subsequent NRA's will be released on a rotating two year cycle.

The development of a space life science research program based on the use of rotational facilities is described. In-flight and ground centrifuges can be used as artificial gravity environments to study the following: nongravitational biological factors; the effects of 0, 1, and hyper G on man; counter measures for deconditioning astronauts in weightlessness; and the development of suitable artificial gravity for long-term residence in space. The use of inertial fields as a substitute for gravity, and the relations between the radius of the centrifuge and rotation rate and specimen height and rotation radius are examined. An example of a centrifuge study involving squirrel monkeys is presented.

Development is considered to encompass all aspects of the mammalian life span from initial initial germ cell production through the complete life cycle to death of the organism. Thus, gamete production, fertilization, embryogenesis, implantation, fetogenesis, birth, peri- and postnatal maturation, and aging were all considered as stages of a development continuum relevant to problems of Space Biology. Deliberations thus far have been limited to stages of the development cycle from fertilization to early postnatal life. The deliberations are detailed.

Brief sketches of developmental biology studies during spaceflight presented are intended to be complete in scope and to provide the reader with an overview of the present status of such studies. Means of evaluating both the direct role of gravity on all processes of mammalian reproduction and development as well as defining the means of assessing indirect transplacemental aspects are considered. The potential present in the development of a spaceflight system/program specifically designed to provide chronic exposure of a representative variety of mammalian species with periodic sampling for multiple generations to fully assess the potential impact of an altered gravitational vector on general mammalian development is also considered.

Research on the precise timing and regulation of neuron production and maturation in the vestibular and visual systems of Wistar rats and several inbred strains of mice (C57B16 and Pallid mutant) concentrated upon establishing a timing baseline for mitotic development of the neurons of the vestibular nuclei and the peripheral vestibular sensory structures (maculae, cristae). This involved studies of the timing and site of neuronal cell birth and preliminary studies of neuronal cell death in both central and peripheral elements of the mammalian vestibular system. Studies on neuronal generation and maturation in the retina were recently added to provide a mechanism for more properly defining the in utero' developmental age of the individual fetal subject and to closely monitor potential transplacental effects of environmentally stressed maternal systems. Information is given on current efforts concentrating upon the (1) perinatal period of development (E18 thru P14) and (2) the role of cell death in response to variation in the functional loading of the vestibular and proprioreceptive systems in developing mammalian organisms.

Data obtained from a staged series of single paired injections of tritiated thymidine to pregnant Wistar rats or C57B16/j mice on selected embryonic days and several postnatal times are reported. All injected specimens were allowed to come to term, each litter culled to six pups and specimens were sacrificed on PN28, with fixation and embedding for paraffin and plastic embedding. The results are derived from serial paraffin sections of PN28 animals exposed to autoradiographic processing and plotted with respect to heavily labelled cell nuclei present in the selected brain stem nuclei and sensory ganglia. Counts from each time sample/structure are totalled and the percentage of cells in the total labelled population/structure represented by each injection time interval plotted.

The current status of gravitational biology is summarized, future areas of required basic research in earth-based and spaceflight projects are presented, and potential applications of gravitational biology on a space station are demonstrated. Topics covered include vertebrate reproduction, prenatal/postnatal development, a review of plant space experiments, the facilities needed for growing plants, gravimorphogenesis, thigmomorphogenesis, centrifuges, maintaining a vivarium, tissue culture, and artificial human organ generation. It is proposed that space stations carrying out these types of long-term research be called the National Space Research Facility.

The timing of cell generation (onset and duration) in the developing rat vestibular and proprioceptive systems is investigated. The results clearly indicate a defined time-span for generation of all neurons in the central nervous system nuclei studied. This cytogenetic period in both vestibular and proprioceptive sensory nuclei is determined to occur during and immediately after placentation, a potentially critical period for spaceflight exposure due to alterations in maternal physiology.

The potential effects of spaceflight on the processes of mammalian fertilizaton, implantation and embryonic development are investigated. Five female and two male rats were placed together on Day 2 of the flight. By R+17, it was determined that both flight and synchronous females were not carrying normal pregnancies and three of the flight animals were laparotomized. The uterus and ovaries were processed for microscopic analyses. The two remaining flight females were allowed to recover from the exploratory operation, rebred with flight males and delivered normal litters. As a control for potential transplacental effects that might be interpreted as direct spaceflight effects, a series of fertilized Japanese quail (Coturnix japonica) eggs was flown on Cosmos 1129. Although all of the eggs were adversely impacted by an inflight failure of the incubator humidifier on flight Day 13, several embryos were able to progress to a developmental stage equivalent to that of a control 10-12 Day embryo.

The killifish Fundulus heteroclitus was used as a model system for study of embryonic development and vestibular adaptation in orbital flight. Juvenile fish in a zero gravity environment exhibited looping swimming activity similar to that observed during the Skylab 3 mission. Hatchings from a 336 hour egg stage were also observed to loop. At splashdown, both juveniles and hatchings exhibited a typical diving response suggesting relatively normal vestibular function. Juveniles exhibited swimming patterns suggestive of abnormal swim bladders. The embryos exhibited no abnormalities resulting from development in a zero gravity environment.

Results from the Kosmos Biosatellite 782 flight are presented. Experiments with fish hatchlings are discussed along with postflight observation and testing. The preparation of fertilized eggs for the experiments is described.