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Human activities in space must include life in a confined, artificial and isolated environment. We investigated the mental and physiological status of four crewmembers undergoing repeated seven-day habitation in an advanced life support system. In order to monitor the psycho-physiological stresses, saliva cortisol and urinary adrenaline were sampled and visual-analog scale was serially recorded. As a result, saliva cortisol and urinary adrenaline levels were higher in pre- and post habitation. Psychological scales showed a relatively relaxed mood during habitation, indicating that the crew experienced stress in the pre- and post seven-day habitation periods. The periods of environmental change such as those pre-and post habitation seem to be critical for monitoring the health of crew performing analogous missions.

Two-week closed habitation experiments were repeated three times using Closed Ecology Experiment Facilities (CEEF) to evaluate the capability of advanced life support systems. The CEEF is a two-manned system. Four crew members, termed econauts, inhabited the CEEF, taking turns at one-week shifts in pairs. Each econaut underwent three habitations. In order to evaluate the state of health of the crew, medical examinations were carried out before, immediately after and two months after the series of habitations. Physical data such as blood pressure, body temperature and body weight were monitored during each habitation. In 2005, though calorie intake and expenditure were well balanced, a temporary reduction in body weight was observed. As a countermeasure in 2006, econauts began their habitation diet one week before habitation to adapt their condition. As a result, total serum cholesterol significantly decreased after the series of habitations.

The CEEF (Closed Ecology Experiment Facilities) was constructed for collecting data on carbon transfer from the atmosphere to crops, livestock and humans by conducting material circulation experiments, including the habitation of humans and animals and growing crops which supply food and feed, within a closed environment. The main objective of the CEEF project involves understanding the transfer of radiocarbon in the environment via experiments using stable carbon isotopes. On the other hand, the project is also a good example demonstrating human life in ecosystem material circulation. Many people visited and toured the CEEF and the project has been introduced by the media. The candidate inhabitants, who were selected for the project following medical and psychological testing, are called “eco-nauts”. The CEEF project was introduced and eco-nauts participated in events with the intention of educating the public on the human impacts on an ecosystem made by a science museum.

The Closed Ecology Experiment Facilities (CEEF) were installed to collect data for realistic estimation of radiocarbon transfer in the ecosystem. Two-week experiments were conducted three times from September to November of 2006, in which two human subjects called as eco-nauts were enclosed and worked in an airtight facility, the CEEF. The eco-nauts were changed after a week from beginning of each experiment. In these experiments, a Plant Module (PM) with 23 crops, including rice, soybean, peanut, and sugar beet, was connected to an Animal & Habitation Module (AHM) which included the eco-nauts and two goats. 91.8-94.6% (by weight) of the food consumed by the eco-nauts and 79% of the feed to the goats (straw, leaf and bran of rice, leaf and stem of soybean, and leaf, stem and shell of peanut) were produced from crops in the PM. Amount of oxygen produced by the crops was more than the amount consumed by respiration of human and animals in these experiments.

Before a series of overall material circulation in an experimental system including crops, animals and humans, technical examinations for the development of a waste processing system were conducted for incorporating the system to the Closed Ecology Experiment Facilities (CEEF). The examinations are intended to validate the function of the carbonization and incineration processing units which were installed in the CEEF in 2006. Using different mock-up samples, examinations have been carried out to verify the function and capability of the whole system, including the waste carbonization processing unit, incineration processing unit, exhaust gas tank and the exhaust gas processing unit. In an examination using filter paper pulp as a mock-up sample, processing time in each unit was checked. The processing times needed for carbonization and incineration processing were 5.7 and 2.6 hours, respectively.

The Closed Ecology Experiment Facilities (CEEF) were installed to collect data for estimation of transfer of radionuclides from atmosphere to humans in the ecosystem. The first target among the radio-nuclides is 14C. In order to validate function of material circulation in an experimental system constructed in the CEEF, circulation of air constituents, water and materials in waste was demonstrated connecting the Closed Plant Experiment Facility (CPEF) and the Closed Animal and Human habitation Experiment Facility (CAHEF) of the CEEF, since 2005 to 2007. The CPEF has a Plant Cultivation Module (PCM), which comprises of three plant chambers illuminated solely by artificial lighting, one plant chamber illuminated by both natural and artificial lighting, a space for preparation, and an airlock, and a physical/chemical material circulation system.

Three 1-week experiments were conducted from September to October of 2005 in which two human subjects called as eco-nauts were enclosed and worked in an airtight facility called Closed Ecosystem Experiment Facilities (CEEF). The test involved connecting a Plant Module (PM) with 23 crops, including rice, soybean, peanut, and sugar beet, to an Animal & Habitation Module (AHM), which included the eco-nauts and two Shiba goats. Although only 34% (by weight) of the food consumed by the eco-nauts was produced by crops in the PM in the first experiment, it was 81% in the second and third experiments. As for feed for the goats, although all was Timothy hay was supplied from outside in the first experiment, all of the feed (rice straw, soybean leaf and peanut shell) was produced in the PM in the second and third experiments. In all these experiments, the crops produced more oxygen than the amount consumed by respiration of human and animals.

Closed Ecology Experimental Facilities, CEEF, is designed to regenerate everything required for living, such as air, water, and food. Researchers called “econauts” play a crucial role in maintaining the system in good order. CEEF must involve confinement, which is one of the major factors responsible for deterioration in crew health and performance. Two econauts repeated 7-day habitation in the CEEF 3 times in 2005. Blood cells, hormones and mood status were analyzed. Although clinically no problem, changes of mood status and a stress hormone correlated in an econaut. Characteristic changes were observed in leukocyte ratio. These data are essential in considering the effects of forthcoming long-term habitation in CEEF.

The Closed Ecology Experimental Facilities (CEEF), is designed to simulate material circulation, and is an artificial closed agricultural ecosystem with plants, humans and animals. The first seven-day air circulated confinement experiments using the CEEF were conducted three times. The experiments included psychological monitoring of two crew members named “Eco-nauts”. Even though there was some trouble with the CEEF regarding the atmospheric gases (which one of the Eco-nauts discovered himself), all three experiments were completed without critical problems and both Eco-nauts maintained a stable psychological status. Through the experiments, it was found that the interior environment of the CEEF could fluctuate within short time periods, and that frequent monitoring by the instantaneous and sensitive Face Scale Test allowed scoring of the Eco-nauts' response to such fluctuations.

In FY2005, the first series of seven-day closed habitation experiments was conducted using the Closed Ecology Experiment Facilities (CEEF). The operation period of CEEF is planned to be extended to four months by FY2009. The CEEF is a two-manned system. The habitants, called “Eco-nauts”, are responsible for operating the system as a part of an artificial environment. Therefore, their continuous health checks are very important to the success of the habitation experiments. To check their health condition, medical examinations were carried out before, right after and two months after the series of experiments. During each experiment, physical data were obtained and evaluated by medical doctors using a web-video-meeting system. The primary objective of this study was to verify if the schedule and examinations selected for the health check of the Eco-nauts were successfully carried out.

Preliminary seven-day habitation experiments without complete closure of the habitation module were performed in the Closed Ecology Experiment Facilities (CEEF) to obtain information for the closed habitation and to prepare for the actual closed habitation experiments to be launched in September 2005. Energy requirements have been estimated for habitant candidates in closed habitation experiments (to be called Eco-nauts). This paper presents the calculations of Eco-nauts' energy requirements using records of life activities during the preliminary experiments and compares them with the expected energy supply from the CEEF.

The Closed Ecological Experimental Facilities (CEEF), designed to simulate material circulation, is an artificial closed agricultural ecosystem with plants, humans and animals. In the experiments starting from FY2005, habitants referred to as eco-nauts will be exposed to complex workloads and various CEEF environmental factors, which may influence their physio-psychological state, and lower their performance. Therefore, preliminary experiments were conducted on the workload-matched (11.1h work, 168h, airlock open) and the environment-matched condition (6.9h work, 24h, air circulation) to monitor physio-psychological changes. As a result, both experiment types were conducted as scheduled without any major problems, and no serious physio-psychological disorders were observed in the eco-nauts. One week closed habitation experiments will be performed as a preliminary step toward much longer (max. 4 months) experiments.