空间增材制造技术的应用

中国空间站旨在进行大量在轨科学实验和空间应用研究,在轨保障是支持空间站在全寿命周期内完成载人航天任务的重要途径.传统地面制造及上行补给方式难以满足较大规模应用的需求,亟需一种创新性的保障模式突破资源瓶颈,空间增材制造技术具有极大的潜力实现即造即用的资源保障模式.本文根据空间增材制造技术的最新研究进展,结合中国空间站和载人深空探测任务需求,对空间增材制造技术的在轨应用模式进行分析,提出了中国空间增材制造技术未来发展所面临的问题和解决途径.      

Creation of biological module for self-regulating ecological system by the way of polymerization of composite materials in free space.

The large-size frame of space ship and space station can be created with the use of the technology of the polymerization of fiber-filled composites and a liquid reactionable matrix applied in free space or on the other space body when the space ship or space station will be used during a long period of time. For the polymerization of the station frame the fabric impregnated with a long-life polymer matrix (prepreg) is prepared in terrestrial conditions and, after folding, can be shipped in a compact container to orbit and kept folded on board the station. In due time the prepreg is carried out into free space and unfolded. Then a reaction of matrix polymerization starts. After reaction of polymerization the durable frame is ready for exploitation. After that, the frame can be filled out with air, the apparatus and life support systems. The technology can be used for creation of biological frame as element of self regulating ecological system, and for creation of technological frame which can be used for a production of new materials on Earth orbit in microgravity conditions and on other space bodies (Mars, Moon, asteroids) for unique high price mineral extraction. Based on such technology a future space base on Earth orbit with volume of 10(6) m3 and a crew of 100 astronauts is considered.     

CELSS transportation analysis

Regenerative life support systems based on the use of biological material have been considered for inclusion in manned spacecraft since the early days of the United States space program. These biological life support systems are currently being developed by NASA in the Controlled Ecological Life Support System (CELSS) program. Because of the progress being achieved in the CELSS program, it is time to determine which space missions may profit from use of the developing technology. This paper presents the results of a study that was conducted to estimate where potential transportation cost savings could be anticipated by using CELSS technology for selected future manned space missions.

Six representative missions were selected for study from those included in NASA planning studies. The selected missions ranged from a low Earth orbit mission to those associated with asteroids and a Mars sortie. The crew sizes considered varied from four persons to five thousand. Other study parameters included mission duration and life support closure percentages, with the latter ranging from complete resupply of consumable life support materials to 97% closure of the life support system. The paper presents the analytical study approach and describes the missions and systems considered, together with the benefits derived from CELSS when applicable.     

Studies on urine treatment by biological purification using Azolla and UV photocatalytic oxidation

The amount of water consumed in space station operations is very large. In order to reduce the amount of water which must be resupplied from Earth, the space station needs to resolve the problems of water supply. For this reason, the recovery, regeneration and utilization of urine of astronauts are of key importance. Many investigations on this subject have been reported. Our research is based on biological absorption and, purification using UV photocatalytic oxidation techniques to achieve comprehensive treatment for urine. In the treatment apparatus we created, the urine solution is used as part of the nutrient solution for the biological components in our bioregenerative life support system. After being absorbed, the nutrients from the urine were then decomposed, metabolized and purified which creates a favorable condition for the follow-up oxidation treatment by UV photocatalytic oxidation. After these two processes, the treated urine solution reached Chinese national standards for drinking water quality (GB5749-1985).     

An integrated Engineered Closed/Controlled EcoSystem for a lunar base.

Long-term human missions in space, such as the establishment of a human-tended lunar base, require autonomous life support systems. A Lunar Engineered Closed/Controlled EcoSystem (LECCES) can provide autonomy by integrating a human module with support plant and animal modules, and waste treatment subsystems. Integration of physical/chemical (P/C) and biological waste treatment subsystems can lead to viable and operational bioregenerative systems that minimize resupply requirements from Earth. A top-level diagram for LECCES is developed based on the human module requirements. The proposed diagram is presented and its components are discussed.     

Aquatic food production modules in bioregenerative life support systems based on higher plants.

Most bioregenerative life support systems (BLSS) are based on gravitropic higher plants which exhibit growth and seed generation disturbances in microgravity. Even when used for a lunar or martian base the reduced gravity may induce a decreased productivity in comparison to Earth. Therefore, the implementation of aquatic biomass production modules in higher plant and/or hybrid BLSS may compensate for this and offer, in addition, the possibility to produce animal protein for human nutrition. It was shown on the SLS-89 and SLS-90 space shuttle missions with the C.E.B.A.S.-MINI MODULE that the edible non gravitropic rootless higher aquatic plant Ceratophyllum demeresum exhibits an undisturbed high biomass production rate in space and that the teleost fish species, Xiphophorus helleri, adapts rapidly to space conditions without loss of its normal reproductive functions. Based on these findings a series of ground-based aquatic food production systems were developed which are disposed for utilization in space. These are plant production bioreactors for the species mentioned above and another suitable candidate, the lemnacean (duckweed) species, Wolffia arrhiza. Moreover, combined intensive aquaculture systems with a closed food loop between herbivorous fishes and aquatic and land plants are being developed which may be suitable for integration into a BLSS of higher complexity. Grant numbers: WS50WB9319-3, IVA1216-00588.     

Sunlight supply and gas exchange systems in the microalgal bioreactor.

The bioreactor with sunlight supply system and gas exchange systems presented here has proved feasible in ground tests and shows much promise for space use as a CELSS device. Our chief conclusions concerning the specification of total system needed for a life support system for a man in a space station are the following. (1) Sunlight supply system: compactness and low electrical consumption. (2) Bioreactor system: high density and growth rate of chlorella. (3) Gas exchange system: enough for O2 production and CO2 assimilation.     

The James Webb Space Telescope (JWST)

The James Webb Space Telescope is a 6.5 m, infrared space telescope designed to be launched in 2013 aboard an Ariane 5. The JWST program is a cooperative program with the Goddard Space Flight Center (GSFC) managing the project for NASA. The prime contractor for JWST is Northrop Grumman Space Technology (NGST). JWST’s international partners are the European Space Agency (ESA) and the Canadian Space Agency (CSA). JWST will address four major science themes: end of the dark ages: first light and reionization; the assembly of galaxies, the birth of stars and protoplanetary systems; and the formation of planetary systems and the origins of life. We discuss the design of the observatory and review recent progress on the JWST program.     

Life support for aquatic species--past; present; future.

Life Support is a basic issue since manned space flight began. Not only to support astronauts and cosmonauts with the essential things to live, however, also animals which were carried for research to space etc. together with men need support systems to survive under space conditions. Most of the animals transported to space participate at the life support system of the spacecraft. However, aquatic species live in water as environment and thus need special developments. Research with aquatic animals has a long tradition in manned space flight resulting in numerous life support systems for them starting with simple plastic bags up to complex support hardware. Most of the recent developments have to be identified as part of a technological oriented system and can be described as small technospheres. As the importance arose to study our Earth as the extraordinary Biosphere we live in, the modeling of small ecosystems began as part of ecophysiological research. In parallel the investigations of Bioregenerative Life Support Systems were launched and identified as necessity for long-term space missions or traveling to Moon and Mars and beyond. This paper focus on previous developments of Life Support Systems for aquatic animals and will show future potential developments towards Bioregenerative Life Support which additionally strongly benefits to our Earth's basic understanding.     

未来的空间生命科学

本文分析了空间生命科学的发展战略,对21世纪初期的研究设想进行了概括,较详细地介绍了空间生命科学四个方面的内容:空间生理学和医学,包括空间医学、空间生理学、空间作业医学和人在空间的作用;空间生物学,包括重力生物学、可控生态生保系统、生物圈和地外生物学;空间站生物医学工程以及空间生物材料的加工生产。本文还讨论了各方面存在的主要问题和今后的发展趋向,特别强调了空间高枝术应用对促进国民经济发展的巨大潜力。     

A large-scale perspective on ecosystems.

Interactions between ecological elements must be better understood in order to construct an ecological life support system in space. An index was devised to describe the complexity of material cyclings within a given ecosystem. It was then applied to the cyclings of bioelements in various systems of material cyclings including the whole Earth and national economies. The results show interesting characteristics of natural and man-made systems.     

BLSS: A contribution to future life support

For extended duration missions in space the supply of basic life-supporting ingredients represents a formidable logistics problem. Storage volume and launch weight of water, oxygen and food in a conventional non-regenerable life support system are directly proportional to the crew size and the length of the mission. In view of spacecraft payload limitations this will require that the carbon, or food, recycling loop, the third and final part in the life support system, be closed to further reduce logistics cost. This will be practical only if advanced life support systems can be developed in which metabolic waste products are regenerated and food is produced.

Biological Life Support Systems (BLSS) satisfy the space station environmental control functions and close the food cycle. A Biological Life Support System has to be a balanced ecological system, biotechnical in nature and consisting of some combination of human beings, animals, plants and microorganisms integrated with mechanical and physico-chemical hardware.

Numerous scientific space experiments have been delineated in recent years, the results of which are applicable to the support of BLSS concepts. Furthermore ecological life support systems have become subject to intensified studies and experiments both in the U.S. and the U.S.S.R. The Japanese have also conducted detailed preliminary studies.

Dornier System has in recent years undertaken an effort to define requirements and concepts and to analyse the feasibility of BLSS for space applications. Analyses of the BLSS energy-mass relation have been performed, and the possibilities to influence it to achieve advantages for the BLSS (compared with physico-chemical systems) have been determined. The major problem areas which need immediate attention have been defined, and a programme for the development of BLSS has been proposed.     

Accumulation and effect of volatile organic compounds in closed life support systems.

Bioregenerative life support systems (BLSS) being considered for long duration space missions will operate with limited resupply and utilize biological systems to revitalize the atmosphere, purify water, and produce food. The presence of man-made materials, plant and microbial communities, and human activities will result in the production of volatile organic compounds (VOCs). A database of VOC production from potential BLSS crops is being developed by the Breadboard Project at Kennedy Space Center. Most research to date has focused on the development of air revitalization systems that minimize the concentration of atmospheric contaminants in a closed environment. Similar approaches are being pursued in the design of atmospheric revitalization systems in bioregenerative life support systems. in a BLSS one must consider the effect of VOC concentration on the performance of plants being used for water and atmospheric purification processes. In addition to phytotoxic responses, the impact of removing biogenic compounds from the atmosphere on BLSS function needs to be assessed. This paper provides a synopsis of criteria for setting exposure limits, gives an overview of existing information, and discusses production of biogenic compounds from plants grown in the Biomass Production Chamber at Kennedy Space Center.     

Integration of lessons from recent research for “Earth to Mars” life support systems

Development of reliable and robust strategies for long-term life support for planetary exploration must be built from real-time experimentation to verify and improve system components. Also critical is incorporating a range of viable options to handle potential short-term life system imbalances. This paper revisits some of the conceptual framework for a Mars base prototype which has been developed by the authors along with others previously advanced (“Mars on Earth^®”) in the light of three years of experimentation in the Laboratory Biosphere, further investigation of system alternatives and the advent of other innovative engineering and agri-ecosystem approaches. Several experiments with candidate space agriculture crops have demonstrated the higher productivity possible with elevated light levels and improved environmental controls. For example, crops of sweet potatoes exceeded original Mars base prototype projections by an average of 46% (53% for best crop) ultradwarf (Apogee) wheat by 9% (23% for best crop), pinto bean by 13% (31% for best crop). These production levels, although they may be increased with further optimization of lighting regimes, environmental parameters, crop density etc. offer evidence that a soil-based system can be as productive as the hydroponic systems which have dominated space life support scenarios and research. But soil also offers distinct advantages: the capability to be created on the Moon or Mars using in situ space resources, reduces long-term reliance on consumables and imported resources, and more readily recycling and incorporating crew and crop waste products. In addition, a living soil contains a complex microbial ecosystem which helps prevent the buildup of trace gases or compounds, and thus assist with air and water purification. The atmospheric dynamics of these crops were studied in the Laboratory Biosphere adding to the database necessary for managing the mixed stands of crops essential for supplying a nutritionally adequate diet in space. This paper explores some of the challenges of small bioregenerative life support: air-sealing and facility architecture/design, balance of short-term variations of carbon dioxide and oxygen through staggered plantings, options for additional atmospheric buffers and sinks, lighting/energy efficiency engineering, crop and waste product recycling approaches, and human factor considerations in the design and operation of a Mars base. An “Earth to Mars” project, forging the ability to live sustainably in space (as on Earth) requires continued research and testing of these components and integrated subsystems; and developing a step-by-step learning process.     

Farming in space: environmental and biophysical concerns.

The colonization of space will depend on our ability to routinely provide for the metabolic needs (oxygen, water, and food) of a crew with minimal re-supply from Earth. On Earth, these functions are facilitated by the cultivation of plant crops, thus it is important to develop plant-based food production systems to sustain the presence of mankind in space. Farming practices on earth have evolved for thousands of years to meet both the demands of an ever-increasing population and the availability of scarce resources, and now these practices must adapt to accommodate the effects of global warming. Similar challenges are expected when earth-based agricultural practices are adapted for space-based agriculture. A key variable in space is gravity; planets (e.g. Mars, 1/3 g) and moons (e.g. Earth's moon, 1/6 g) differ from spacecraft orbiting the Earth (e.g. Space stations) or orbital transfer vehicles that are subject to microgravity. The movement of heat, water vapor, CO2 and O2 between plant surfaces and their environment is also affected by gravity. In microgravity, these processes may also be affected by reduced mass transport and thicker boundary layers around plant organs caused by the absence of buoyancy dependent convective transport. Future space farmers will have to adapt their practices to accommodate microgravity, high and low extremes in ambient temperatures, reduced atmospheric pressures, atmospheres containing high volatile organic carbon contents, and elevated to super-elevated CO2 concentrations. Farming in space must also be carried out within power-, volume-, and mass-limited life support systems and must share resources with manned crews. Improved lighting and sensor technologies will have to be developed and tested for use in space. These developments should also help make crop production in terrestrial controlled environments (plant growth chambers and greenhouses) more efficient and, therefore, make these alternative agricultural systems more economically feasible food production systems.     

Large-size space laboratory for biological orbit experiments.

The study of space factors on living systems has great interest and long-term experiments during orbital flight will be important tool for increasing our knowledge. Realization of such experiments is limited by constraints of modern space stations. A new technology of large-size space laboratory for biological experiments has been developed on the basis of polymerization techniques. Using this technique there are no limits of form and size of laboratory for a space station that will permit long term experiments on Earth orbit with plants and animals in sufficient volume for creation of closed self-regulating ecological systems. The technology is based on experiments of the behavior of polymer materials in simulated free space conditions during the reaction of polymerization. The influences of space vacuum, sharp temperature changes and space plasma generated by galactic rays and Sun irradiation on chemical reaction were evaluated in their impact on liquid organic materials in laboratory conditions. The results of our study shows, that the chemical reaction is sensitive to such space factors. But we believe that the technology of polymerization could be used for the creation of space biological laboratories in Earth orbit in the near future.     

Canadian advanced life support capacities and future directions

Canada began research on space-relevant biological life support systems in the early 1990s. Since that time Canadian capabilities have grown tremendously, placing Canada among the emerging leaders in biological life support systems. The rapid growth of Canadian expertise has been the result of several factors including a large and technically sophisticated greenhouse sector which successfully operates under challenging climatic conditions, well planned technology transfer strategies between the academic and industrial sectors, and a strong emphasis on international research collaborations. Recent activities such as Canada’s contribution of the Higher Plant Compartment of the European Space Agency’s MELiSSA Pilot Plant and the remote operation of the Arthur Clarke Mars Greenhouse in the Canadian High Arctic continue to demonstrate Canadian capabilities with direct applicability to advanced life support systems. There is also a significant latent potential within Canadian institutions and organizations with respect to directly applicable advanced life support technologies. These directly applicable research interests include such areas as horticultural management strategies (for candidate crops), growth media, food processing, water management, atmosphere management, energy management, waste management, imaging, environment sensors, thermal control, lighting systems, robotics, command and data handling, communications systems, structures, in-situ resource utilization, space analogues and mission operations. With this background and in collaboration with the Canadian aerospace industry sector, a roadmap for future life support contributions is presented here. This roadmap targets an objective of at least 50% food closure by 2050 (providing greater closure in oxygen, water recycling and carbon dioxide uptake). The Canadian advanced life support community has chosen to focus on lunar surface infrastructure and not low Earth orbit or transit systems (i.e. microgravity applications). To advance the technical readiness for the proposed lunar missions, including a lunar plant growth lander, lunar “salad machine” (i.e. small scale plant production unit) and a full scale lunar plant production system, a suite of terrestrial developments and analogue systems are proposed. As has been successfully demonstrated by past Canadian advanced life support activities, terrestrial technology transfer and the development of highly qualified personnel will serve as key outputs for Canadian advanced life support system research programs. This approach is designed to serve the Canadian greenhouse industry by developing compliance measures for mitigating environmental impact, reducing labour and energy costs as well as improving Canadian food security, safety and benefit northern/remote communities.     

Survival of microorganisms in space protected by meteorite material: results of the experiment 'EXOBIOLOGIE' of the PERSEUS mission.

During the early evolution of life on Earth, before the formation of a protective ozone layer in the atmosphere, high intensities of solar UV radiation of short wavelengths could reach the surface of the Earth. Today the full spectrum of solar UV radiation is only experienced in space, where other important space parameters influence survival and genetic stability additionally, like vacuum, cosmic radiation, temperature extremes, microgravity. To reach a better understanding of the processes leading to the origin, evolution and distribution of life we have performed space experiments with microorganisms. The ability of resistant life forms like bacterial spores to survive high doses of extraterrestrial solar UV alone or in combination with other space parameters, e.g. vacuum, was investigated. Extraterrestrial solar UV was found to have a thousand times higher biological effectiveness than UV radiation filtered by stratospheric ozone concentrations found today on Earth. The protective effects of anorganic substances like artificial or real meteorites were determined on the MIR station. In the experiment EXOBIOLOGIE of the French PERSEUS mission (1999) it was found that very thin layers of anorganic material did not protect spores against the deleterious effects of energy-rich UV radiation in space to the expected amount, but that layers of UV radiation inactivated spores serve as a UV-shield by themselves, so that a hypothetical interplanetary transfer of life by the transport of microorganisms inside rocks through the solar system cannot be excluded, but requires the shielding of a substantial mass of anorganic substances.     

Progress of Earth Observation in China

China is expanding and sharing its capacity for Earth observation by developing sensors, platforms, and launch capabilities in tandem with growing lunar and deep space exploration. China is considering the Moon as a viable Earth observation platform to provide high-quality, planetary-scale data. The platform would produce consistent spatiotemporal data because of its long operational life and the geological stability of the Moon. China is also quickly improving its capabilities in processing and transforming Earth observation data into useful and practical information. Programs such as the Big Earth Data Science Engineering Program (CASEarth) provide opportunities to integrate data and develop "Big Earth Data" platforms to add value to data through analysis and integration. Such programs can offer products and services independently and in collaboration with international partners for data-driven decision support and policy development. With the rapid digital transformation of societies, and consequently increasing demand for big data and associated products, Digital Earth and the Digital Belt and Road Program (DBAR) allow Chinese experts to collaborate with international partners to integrate valuable Earth observation data in regional and global sustainable development.