50 YEARS or more have passed since the first human trip into space, and research and development of Environmental Control and Life Support System, ECLSS, corresponding to various missions have been carried out. Some detailed studies of long duration missions were performed as early as the 1960's and 1970's. Different mission scenarios, such as short term and long term missions, are reflected in the ECLSS design, and the most appropriate ECLSS is different for each mission.
At present, human beings at the International Space Station, ISS, can remain in space for a long term with ECLSS recycling water and oxygen. In the future, examination, research, and development of new life support systems will be required in preparation for exploration of the lunar outpost and manned Mars exploration. As for the development of ECLSS corresponding to these missions, the scale expands and becomes complex, and controlling whole resource recycling becomes more important. A short term mission can use a simple ECLSS that does not perform resource recycling, whereas a long term mission, such as the ISS or a manned Mars exploration, needs resource recycling to reduce resupply, storage requirements and cost.
For supporting these investigations, we are developing new simulation software called SImulator for Closed Life and Ecology, SICLE, which simulates resource recycling and control of the ECLSS. At present, SICLE has operability and expandability, and it is able to help study of closed ecosystem. In addition, we have been improving SICLE to fit for other fields such as logistics.
Resource recycling in the ECLSS is to recycle substances that are needed for human activity and emission matters by utilizing plants and physicochemical devices. Water, oxygen, carbon dioxide and nitrogen are the main component substances. Though some simulators that can simulate resource recycling have been released in the past, we have been developing a simulator with the three following features to accommodate research and development of more diversification and complex life support system.
First, it is important to use a design concept that is based on scientific results. SICLE is a simulator designed based on the scientific results that have supported research of advanced life support system in a real ECLSS research facility, CEEF.
Second, it is important to have an interface that attached importance to direct operability. In a life support system that a large variety of resources and devices cooperate complicatedly, it is important to cognize the detail setting of each device from grasp of system perspective visually and easily. Therefore, SICLE enables a selection operation of the device by icons and making of block diagrams for a designer can design systems easily. In addition, we can grasp and trace the process of simulation visually and change the status such as a device stop and trouble even though SICLE is running.
Finally, it is important to be a software structure including expandability. In order to enable inserting various devices in simulation, SICLE provides a function to easily model various resource recycling systems such as producing and implementing user defined new device and human beings-plant model. Furthermore, SICLE adopts a class structure and algorithm including expandability for applicable to other field.
SICLE provides ECLSS simulations, which can consistently carry out system design, simulation practice and data analysis. It can confirm and grasp a state of simulation anytime. You can easily set up system and change parameters, and can execute and analyze the simulation of various patterns.
The Mars Desert Research Station (MDRS), which is owned and operated by the Mars Society, is a simulated Mars Analogue Research Station in the Utah desert. As the member of the Team NIPPON that consisted of researchers from Japan who conducted a mission at the MDRS as Crew 137 from March 1 to March 15, 2014 and as Crew 165 from March 5 to March 20, 2016, we collected valuable data for further development of SICLE simulations. The crew handled a strong request for conserving water during the MDRS mission through carefully planned cooking and dish washing and reducing showers and toilet flushing. Meanwhile, the measurement of the amount of water supply and drainage was one of the significant research items on this mission, which consequently provided invaluable data of water consumption required for living with a restricted water supply for two weeks.
Inspiration Mars Mission Design Winner Team Kanau
In the summer of 2014, The Mars Society held an international student design competition, Inspiration Mars Student Design Contest. Inspiration Mars is a manned spaceflight mission to Mars driven by Inspiration Mars Foundation. The main concept described in its architecture study report and feasibility analysis paper is sending two Americans, one male and one female, into free-return orbit to Mars in 2018 so that the journey takes only 501 days owning to the special orbital positioning between Earth and Mars. Team Kanau is one of the student competition entry groups that consisted of students and young professionals from Japan and U.S. Team Kanau's mission design won the first prize in the final presentation. Since ECLSS analysis is the key factor of this long duration mission design, we collaborated with Team Kanau to determine an optimal system design, especially to decide the size of recycling tanks, offering SICLE as its simulation software.