ISS Utilization: EDEN
EDEN ISS — Ground Demonstration of Plant Cultivation Technologies for Safe Food Production in Space
Plant cultivation in large-scale closed environments is challenging and several key technologies necessary for space-based plant production are not yet space-qualified or remain in early stages of development. The EDEN ISS project foresees development and demonstration of higher plant cultivation technologies, suitable for future deployment on the International Space Station and from a long-term perspective, within Moon and Mars habitats. The EDEN ISS consortium will design and test essential plant cultivation technologies using an International Standard Payload Rack form factor cultivation system for potential testing on-board the International Space Station. Furthermore, a Future Exploration Greenhouse will be designed with respect to future planetary bio-regenerative life support system deployments. The technologies will be tested in a laboratory environment as well as at the highly-isolated German Antarctic Neumayer Station III. A small and mobile container-sized test facility will be built in order to provide realistic mass flow relationships. In addition to technology development and validation, food safety and plant handling procedures will be developed. This paper describes the goals and objectives of EDEN ISS and the different project phases and milestones. Furthermore, the project consortium will be introduced and the role of each partner within the project is explained.1) 2)
EDEN ISS is a 4-year project under the European Union‘s Research and Innovation Action program Horizon 2020, within the topic of ‘Space exploration / Life support.' The project started March 2015 and will conclude February 2019. 3)
Humanitie's plans to further explore space strongly suggest the development of BLSS (Bio-regenerative Life Support Systems) fully incorporated into space stations, transit vehicles and eventually in habitats on the Moon and Mars. These concepts aim to decrease the (re-)supply mass by (re-)generating essential resources for humans through biological processes. Within a BLSS, the cultivation of higher plants takes a crucial role as they can contribute to all major functional aspects (e.g. food production, carbon dioxide reduction, oxygen production, water recycling and waste management). Furthermore, fresh crops are not only beneficial for human physiological health, but also have a positive impact on crew psychological well-being. Adding up these features, higher plants represent a unique asset that makes the investigation of their cultivation in closed systems an essential endeavor. However, cultivation in closed environments is challenging and several key technologies necessary for space-based plant production are not yet space-qualified or remain in early stages of development. The EDEN ISS project develops and demonstrates higher plant cultivation technologies, suitable for future deployment on the ISS (International Space Station) and from a long-term perspective, within Moon and Mars habitats.
The EDEN ISS consortium will design and test essential CEA (Controlled Environment Agriculture) technologies using an ISPR (International Standard Payload Rack) sized cultivation system for potential testing on-board the ISS. Furthermore, a FEG (Future Exploration Greenhouse) will be designed with respect to future planetary BLSS deployments. The technologies will be tested in a laboratory environment as well as at the highly-isolated Antarctic Neumayer Station III, operated by the AWI (Alfred Wegener Institute). A small and mobile container-sized test facility will be built in order to provide realistic mass flow relationships for the ISPR section and FEG. In addition to technology development and validation, food quality tests and safety and plant handling procedures will be developed. These are integral aspects of the interaction between the crew and plants within closed environments.
Objectives: The EDEN ISS project aims to validate selected subsystems and key technologies up to a TRL of 6. Therefore, the project will demonstrate operational capability of key technologies in an environment, similar in certain relevant characteristics to space. A dedicated test campaign at the Neumayer Station III in Antarctica is planned, where a deployed mobile test facility will be operated by an isolated overwintering crew of nine members. This deployment will also be a preparatory research activity for a future plant production system for the ISS.
The defined objectives go hand in hand with a number of international advisory groups and their respective roadmaps. As an example, the project will address several key issues of the THESEUS (Towards Human Exploration of Space: a European Strategy) roadmap, which was developed under the lead of the European Science Foundation. Especially, the issues mentioned in the theme "Life support: management and regeneration of air, water and food of Cluster 4: Habitat Management" highlighted the necessity to further develop BLSS.
The EDEN ISS project also addresses several common goals of the Global Exploration Roadmap: Common Goals and Objectives of Space Exploration. This roadmap was defined by ISECG (International Space Exploration Coordination Group) in cooperation with several international space agencies (e.g. ESA, NASA, CSA and JAXA).
The main goal of EDEN ISS is: The adaptation, integration, fine-tuning and demonstration of higher plant cultivation technologies and operation procedures for safe food production on-board ISS and for future human space exploration missions.
Table 1: Six objectives are identified to achieve this goal
Main leading ideas: Despite the fact that high-closure BLSS are not required for short-duration missions, it is well accepted that they are a required element for sustained human presence in space. Plants flown on various space-based platforms from Salyut to ISS have until now been used to further our understanding of the effects of the spaceflight environment on plant growth and to enhance the technology required for the maintenance of a sufficiently controlled on-orbit growth environment. While small-scale payloads have been sufficient to address these two aims, it is now becoming technically feasible to incorporate larger-scale on-orbit facilities that can provide fresh food on-board. The all-in-one approach of implementing higher plants in BLSS (i.e. air, water, waste recycling, as well as food production and improved crewmember well-being) has a huge advantage for future human space exploration missions. But this approach first needs to be tested on Earth and ISS in order to prove its reliability and applicability. Therefore, the main leading ideas can be summarized as following:
• The project will assemble existing CEA (Controlled Environment Agriculture) knowledge and technologies into a system suitable for safe food production under the constraints posed by the ISS and future human space exploration missions.
• The project will test a greenhouse and its interaction with an isolated crew in one of the most relevant space analogues on Earth.
• The project will develop and exploit the terrestrial potential of the foreground knowledge and technologies.
EDEN ISS considers the near- to mid-term development pathway of BLSS technologies and operational protocols from terrestrial laboratory to utilization on-board ISS. In particular, the EDEN ISS project focuses explicitly on transferring already tested laboratory technologies into relevant operational use at a crewed space analogue site.
Embedded in these near-term objectives is the long-term objective of large-scale plant production facilities. The commonalities between planetary surface and microgravity-based systems will be emphasized in the project so as to maximize the concurrent advancement of BLSS technologies and operational protocols for both applications.
The pull of space technology for low mass, low volume, low power and minimal waste systems is more and more relevant to terrestrial systems where plants are themselves a required element for our survival. The similarities in technical challenges of spaceborne and those of remote and harsh environments such as Antarctica will yield opportunities for the European agricultural industry.
Approach: The project approach foresees the test of a food production system, suitable for ISS and beyond in a mobile test facility under mission relevant conditions. Here, the focal point of the mobile test facility is the demonstration and validation of the different key technologies and the necessary procedures for safe food production within a (semi -) closed system. The mobile test facility provides the necessary resources for simulating relevant ISS environmental parameters and interfaces, but also a future human outpost environment and the transit mission elements. The test facility is built-up in a multi-section shipping container consisting of a:
• Service section,
• ISPR (International Standard Payload Rack) section,
• FEG (Future Exploration Greenhouse).
Figure1 illustrates a possible internal configuration of the mobile test facility. The actual detailed design will be elaborated during the planned concurrent engineering study in autumn 2015.
Figure 1: Draft internal configuration of the mobile test facility (EDEN ISS Team)
The main purpose of the service section is the provision of all necessary resources to the greenhouse sections (ISPR, FEG). The service section houses the support subsystems for the facility and is connected via feed lines with the two other sections (e.g. thermal, power, air ventilation subsystems). Furthermore, the service section offers working space for pre- and post-harvest procedures, a seedling station and other support systems (e.g. monitoring, and sterilization equipment). An airlock segment will be implemented in order to prevent microbial cross-spreading (e.g. bacteria, fungus) between the greenhouse sections as well as the outside.
The ISPR section comprises two full ISPR cultivation systems so that different hardware tests can be accomplished in parallel, as well as to offer the possibility to cultivate different crops at the same time. It will be possible to test different closure scenarios with respect to surrounding environment, both for the air and water loop. As an example, exchanging air with the surrounding environment will increase the possibility of spreading contaminants to other parts of the mobile test facility, while reducing the need for a dedicated air management system within the ISPR cultivation system, thus increasing available growth area.
The FEG consists of a highly adaptable multi shelf growth system and is focused primarily on the large-scale facilities envisioned for planetary surface outputs while also ensuring that the overall mobile test facility provides sufficient food output to further enhance its benefit to Neumayer III crewmembers. Different variable compartments can be built within the FEG in order to establish different environmental settings. Important to note, is the fact that, when possible, the FEG uses the same or similar technologies as used within the ISPR cultivation system, but in a scaled-up configuration. This is particularly relevant with respect to the lighting system, nutrient delivery system, and plant health monitoring and air management.
In addition to testing CEA technologies, the mobile test facility offers the unique possibility to demonstrate and validate different food quality and safety procedures. Various plant operation procedures will be tested under the same regulations and restrictions already in place for the ISS. Furthermore, post-harvest procedures can be tested with high accuracy. Here, the focus is set on the right definition of working steps (e.g. correct seeding, transplantation into the plant trays, maintenance work algorithms preventing contamination, harvest procedures) but also on the selection and demonstration of promising sanitation technologies in order to increase food shelf life.
Concentrating on the key issue of cultivating healthy plants from germination to harvest, dedicated plant health monitoring infrastructure will be implemented in the mobile test facility. Therefore, sensors and monitoring devices (digital, analog, visual) will be utilized to monitor and control plant growth, and to detect pathogens during all growth phases. Collected system health data, environment data and images will be saved and sent via a satellite link from the facility. To enhance production reliability further, a backroom operations team composed of experts from domains such as horticulture, plant physiology, microbiology, engineering and others will have semi-real-time access to this data (telepresence). This team will utilize developed control interfaces to collaboratively interact and subsequently remotely command or interface with the analog test site operations team (Figure 2). Customized SMCD (Science Monitoring Control and Distribution) software will be deployed, which is an application specifically conceived for ISS payload monitoring and commanding. The greenhouse systems will be linked via satellite to the European control center and from there via internet, to the expert communities located at their own UHBs (User Home Bases). This way, consortium partners and European scientists have real-time access to the mobile test facility and provide feedback and advice to the expedition personnel on-site.
Figure 2: Communication links to be established to permit the quasi-real-time greenhouse operational support from the distributed backroom of experts (EDEN ISS Team)
Analog test site:
The list of potential space analog sites is long and includes the oceans, polar regions, deserts, mountains, caves, and unique facilities that currently exist or could be constructed. Each site has its own distinct features that make it more relevant to a particular space analog study. The Neumayer III station in Antarctica has several characteristics that uniquely position it as a valuable analogue for ISS and planetary surface operations. The following features highlight these advantages:
1) Crew size and isolation
The Neumayer Station III crew sizes change depending on the season. Typically there is a main summer team (ca. 50-60 people) that conducts research for 2-3 months, and a small overwintering team (ca. 8-9 people) that keeps the station functional during their 9-10 months of isolation. The size, duration and resupply schedules of the overwintering team aligns well with current ISS operations as well as those typically proposed in Moon and Mars reference missions. In addition to enhancing the desire for increased autonomy of the developed hardware, the crew and isolation factors improve the merit of the proposal with respect to psychological (e.g. group dynamics) and operations/crew time studies. The greenhouse facility will act as a micro-environment which could reduce the stress caused by living in an inhospitable and monotone environment.
2) Inhospitable environment and technology dependency
High winds, heavy snow fall, low temperatures (below -50°C) and seasonal dark periods lasting several months make the Neumayer III test site an extreme environment. Similar to ISS operations, but unlike laboratory-based long-duration isolation studies, Antarctic crewmembers must count on technology to survive. The Neumayer III station crew lives in a highly integrated and technical environment. The environment allows ISS representative study of technology and crew interaction (e.g. psychological tests) and drives, as it does on-orbit, increased system reliability and safety requirements.
3) Extremely low terrestrial biodiversity environment
The Antarctic continent is not only an extremely cold, but also represents one of the most protected and low biodiversity environments on Earth. 4) With this similarity towards Moon and Mars environments, which have no known microbial life, Neumayer III is an optimal testing ground for microbiological experiments. This unique environmental feature allows further investigation of the microbial contamination patterns within the greenhouse, resulting from the habitat and the human interaction (also of high relevance on ISS). Here, planetary protection-adapted contamination measurements can be tested under space analogue conditions.
4) Habitat interface
In order to develop future subsystems of BLSS (Bio-regenerative Life Support Systems) such as integrated ISPR (International Standard Payload Rack) cultivation systems or automated greenhouse modules, the interaction (e.g. water, power, CO2, O2, biomass, bacterial contamination) with the crew/habitat is an essential consideration. As a functional habitat itself, considerations of power, data, food and waste interfaces will be important between Neumayer Station III and the mobile test facility.
The Neumayer III analog test site provides the opportunity to validate complex integrated systems outside the laboratory. The operation of highly integrated systems can be simulated in a laboratory, but an actual deployment with its necessary technological intricacies cannot. The analog deployment will serve to confirm the functionality of concepts and technologies, adding another degree of security and risk mitigation for future ISS and planetary surface BLSS. The complexity of closed systems and the importance of testing closed systems in a relevant mission setting cannot be overemphasized. While laboratory settings provide a useful environment to test and validate components and subsystems the validation of a completely integrated system is best done in a mission analog operation, where the simplicity in operation, maintenance, repair, and control system software is essential. Human factors and human interfaces are important to consider. Especially in small closed systems the close proximity of humans and machines drives the design of the facility and the safety regulations.
The main difference between a laboratory test environment and an analog test site is the fact that the experimenter/operator cannot simply walk away from the system but rather lives with it and, in case of a greenhouse, the crew lives from the output of the greenhouse. The crew is also not able to walk to the next electronics store to replace broken hardware. That puts high demands on reliability and robustness of the system.
Furthermore, there is a huge difference in human resources between a laboratory setting and an analog mission. In a laboratory, one usually has access to a team of scientists, engineers and technicians on site, which are familiar with the system. At an analog test site the personnel is limited, similar to a space mission. There are usually only 1-2 crew members who received extensive training with the system, while the rest of the crew is responsible for other tasks and systems.
The unique aspect of EDEN ISS is the focus on the key technologies and procedures associated with higher plant cultivation. This means that instead of dealing with all the different aspects of a BLSS, the envisioned project focuses on essential target areas. Targeting only these areas, guarantees a higher scientific outcome than spreading the research focus too broadly. Therefore, the EDEN ISS consortium will advance the current state-of-the-art through several means:
• Develop a high fidelity ISPR cultivation system with ~1 m2 production area, thereby enhancing the feasibility of Europe providing the ISS with a plant production facility capable of almost an order of magnitude increase to current systems.
• Deploy a European constructed, highly integrated, mobile greenhouse module test facility to Antarctica. After completion of the project, the test facility will be used for further on-going BLSS investigations and will be open for experiments to the European BLSS community.
• Increase the TRL (Technology Readiness Level) of a microgravity NDS built with materials capable of reducing possible biological contamination and including advanced on-line ion-selective sensors.
• Advance the TRL of spectrally tunable LED (Light-Emitting Diode) lighting systems for highly reliable and remotely operated plant production systems. Energy conservation will be improved through the development and use of advanced LED heat capture techniques and intra-canopy lighting. Experimentally determine optimal light recipes for 5-10 crops and employ these recipes to maximize production within the mobile test facility.
• Increase of the TRL of relevant technologies in the field of bio-detection and decontamination of BLSS.
• Further develop proper plant handling and food safety procedures for higher plant cultivation in closed systems comparable to ISS and future long-duration space missions.
Table 2 provides a summary of the specific advances to the current state-of-the-art for the primary focus areas of the EDEN ISS project.
Table 2: Overview and comparison between state-of-the-art and beyond state-of-the-art
The EDEN ISS consortium consists of 13 organizations from seven different countries, see Table 3 and Figure 3. Each partner brings a balanced set of competencies to the project. However, there remains redundancy for several required competencies to ensure the progress of the project in the event that one partner leaves the project or is significantly behind schedule. It is worth highlighting that the EDEN ISS consortium covers most European companies that are active in space greenhouse research and all partners have already made significant contributions to the aforementioned state-of-the-art. Therefore, the carefully selected partners form a multidisciplinary and highly qualified team, which is fully aware of and well prepared for the scientific challenges of the proposed project.
Table 3: List of EDEN ISS consortium members
In addition, the University of Florida (USA) joined the EDEN ISS project in 2016 as an associate member. The University of Florida team will contribute their expertise and technology associated with imaging technologies that were developed for ISS and suborbital applications, along with spaceflight plant growth and imaging expertise. Multi wavelength imagers will be deployed into the MTF (Mobile Test Facility) to provide early health status information of the crops and used as a tool for remote monitoring of the Antarctic facility. 5)
The University of Florida team, led by Dr. Robert Ferl and Dr. Anna-Lisa Paul is already taking an active role in the project via the testing of spectral imaging hardware in Florida, but also in collaboration with EDEN ISS project partners at Wageningen University. Imagers are planned for deployment in both the Future Exploration Greenhouse and in the ISPR demonstrator and further testing of the developed imaging systems will occur during the assembly, integration and test phase in Bremen, Germany and during the Antarctic operations phase.
Figure 3: The international dimension of the EDEN ISS project consortium (image credit:EDEN ISS Team)
Scientific Advisory Board:
A six member scientific advisory board composed of members from Italy, Germany, Japan, Russia and USA will advise and support the EDEN ISS project. The scientific advisory board will support the research consortium by providing scientific and technical input throughout the evolution of the project. The members of the scientific advisory board will also support the dissemination of project results by assisting in public relation strategies and enhancing the international cooperation and visibility. The members of the scientific advisory board as well as their particular institutes include:
Figure 4: Members of the scientific advisory board and their institutions (image credit: EDEN ISS Team)
EDEN ISS is divided into three major project phases: the design phase, the building phase and the experimental phase. Figure 5 shows the highlights of each phase.
The design phase starts with the KOM (Kick-Off Meeting) in March 2015 and focuses on the requirements definition and design of the greenhouse. The operation modes and experiment schedules are also defined in this phase. After elaborating the initial designs, a concurrent-engineering (CE) study will be conducted in DLR's CEF in Bremen, Germany in September 2015. The objective of the study is the generation of a detailed design of the greenhouse facility. The study will last approximately two weeks and representatives of all consortium partners participating to provide their expertise. This project phase is concluded with the CDR (Critical Design Review) in March 2016.
The building phase encompasses the development, fabrication and integration of subsystems and components. The responsibilities for the different subsystems are divided among the consortium to best fit their experience. In parallel to hardware development, extensive cultivation experiments are performed. With the experiments, the cultivation parameters of the target plants are determined. At the beginning of 2017 the subsystem hardware will be delivered to the DLR in Bremen, Germany for the system AIT (Assembly Integration and Test). AIT will be concluded in August 2017 with a test deployment of the complete greenhouse facility. Following the test deployment, the greenhouse will be prepared for shipping to Antarctica in October 2017.
The experimental phase covers the facility setup in Antarctica, all experiments conducted in Antarctica and the design enhancements based on the lessons-learnt. The selected key technologies and operations procedures will be demonstrated and validated. The results elaborated and the design of the facility and subsystems is further developed to enable terrestrial applications, utilization on-board ISS and in future planetary greenhouse modules.
Figure 5: Project phases and corresponding highlights (image credit: EDEN ISS Team)
In summary, the EDEN ISS project will advance the current state of plant cultivation in space through ground-based demonstration of key technologies. The demonstration of plant cultivation in a large-scale facility at the Neumayer III Station in Antarctica acts as a precursor for future experiments on ISS and strengthens the development of technologies for future missions to Moon and Mars. EDEN ISS will generate and provide scientific data to the whole bio-regenerative life support community. Furthermore, the project will boost the public awareness of plant cultivation in space through its public outreach campaign.
EDEN ISS on the way to Antarctica
The venture to cultivate plants in the Antarctic is gathering momentum: on 8 October 2017 the special EDEN ISS greenhouse container, packed safely away on a cargo ship, left the Port of Hamburg en route to the Ekström ice shelf in the Antarctic. The journey will last approximately 11 weeks. The EDEN ISS team is expected to receive the high-tech greenhouse at the German Neumayer Station III of the AWI (Alfred Wegener Institute) shortly before Christmas. In this project, the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR) is collaborating with international partners to investigate the fully self-sufficient cultivation of vegetables to supply food in harsh climatic environments and for future manned missions to the Moon and Mars. 6)
Figure 6: The loading of EDEN ISS at the port of Hamburg onto a commercial ship to Cape Town (image credit: DLR)
Rich harvest in the trial run: Cucumbers, tomatoes, radishes, peppers, lettuce and herbs flourished in the 12 m container greenhouse during the trial run from late June until August 2017. "The trial run at the DLR site in Bremen yielded a rich harvest," says Project Coordinator Daniel Schubert from the DLR Institute of Space Systems. "We are confident that everything will proceed smoothly in the harsh environment of the Antarctic as well."
In total, the researchers produced over 40 kg of fresh vegetables over the course of the test phase. What makes it so fascinating? There is no loss of water. The only water that leaves the self-sufficient greenhouse system is in the harvested fruits. The rest is recycled and reintroduced into the plants. Under special artificial light, in a temperature-controlled environment without soil and supplied with selected nutrient solutions, the plants can grow faster and more productively than in their natural environment.
Figure 7: On 10 August 2017, we harvested our first tomatoes! Only 3 more weeks of testing at DLR Bremen, before we are sending our greenhouse to Antarctica (image credit: DLR)
The actual crop cultivation experiment in Antarctica will begin in 2018. DLR scientist Paul Zabel will move to the Antarctic, where he will live for one year at the Neumayer III research station and work at the EDEN ISS greenhouse. He will be part of the winter crew staffing the Neumayer III Antarctic station operated by the AWI (Alfred Wegener Institute). "Scientists live and working all year round in the research station, despite the harsh Antarctic. During the summer, there are up to 50 people at the station. In the winter, however, only nine people remain there: one cook, three engineers, one doctor and four scientists," says the long-time Station Manager Eberhard Kohlberg. This is the winter team that Zabel will join as the tenth member.
Team colleagues from the EDEN ISS project will help Zabel with the construction and commissioning of the greenhouse, before leaving him in charge of running the greenhouse and cultivating the crops. The harvest during the months of darkness will enrich the diet of the people at the Neumayer III station. At the same time, the project will imitate the supply scenario for a manned mission to Mars.
"The preparations for the winter sojourn are exciting and already account for much of my day's work," says Zabel. "It gives you an idea of just how painstaking the preparations for a space mission are, when every eventuality has to be considered and one must be prepared for everything." Zabel has already completed survival training in the Alps as a member of the Neumayer III winter team. He has also attended a number of seminars on the technical systems at the station and a one-week fire-fighting training course. And there is still a lot of preparatory work ahead before his departure in December.
Food production of the future: Global food production is among the key societal challenges of the 21st century. The world's rising population, coupled with the simultaneous upheaval associated with climate change, demand new methods to cultivate crops, even in climatically inhospitable regions. A closed greenhouse system will enable crop growth independent of the weather, Sun and season in deserts and low-temperature regions – as well as for future manned missions to the Moon and Mars – while also reducing water consumption and eliminating the need for pesticides and insecticides. The EDEN ISS project will put this model for a future greenhouse through its paces for one year during a long-term trial in the extreme conditions of Antarctica. System assembly is planned for late December 2017 to February 2018. Research operations will follow and are scheduled to run through the Antarctic winter and until December 2018.
EDEN ISS greenhouse reaches Antarctica:
With the arrival and unloading of the EDEN ISS greenhouse at the edge of the Antarctic ice shelf , the construction process has begun. "We can hardly wait, as our four-person construction team set foot on the Antarctic continent before Christmas," says EDEN-ISS Project Manager Daniel Schubert. In the coming weeks, the team from the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR) will set up the greenhouse, designed for extreme environments, just 400 m from the German Neumayer Station III in the Antarctic. It will be run by AWI, which is working on the EDEN ISS project together with DLR. Antarctica is the ideal test site for growing vegetables under artificial light and without soil in a sealed system, where all water is recycled and no pesticides or insecticides are required. The test will demonstrate the cultivation of crop plants in deserts, in areas on Earth with low temperatures, as well as for future manned missions to the Moon and Mars. 7)
Figure 8: Unloading of EDEN ISS in Antarctica in early January 2018 (image credit: DLR)
Christmas and New Year's Eve in the light of the midnight Sun: As the greenhouse was held up for a few days on its journey by sea, the DLR four-person construction team set foot on the Antarctic continent before Christmas. "We can hardly wait to start construction" said EDEN-ISS Project Manager Daniel Schubert. They experienced what it is like to spend Christmas and New Year's Eve in the light of the midnight Sun. "We spent Christmas in the station together with the AWI team," says Schubert. "Standing on the roof of the station at night and enjoying the view was truly special. Even that late in the day you still have to use a sunscreen as the Sun is still shining that strongly." As UTC (Universal Coordinated Time) applies to all of the 50 people living in Neumayer Station III, they welcomed the New Year one hour later than in Germany. "With the Sun above the horizon, it took us a few moments to realize that a new year, and an unbelievably exciting one for us, had started," said DLR researcher Paul Zabel, describing his impressions. "There were no fireworks, because they are not allowed in the Antarctic, but we all toasted to celebrate 2018 and our upcoming joint research."
Figure 9: Localities at the Neumayer III Station on the Antarctic Ekström ice shelf as seen from space by the German TerraSAR-X satellite (image credit: DLR)
Figure 10: Offloading of the EDEN ISS greenhouse in the Antarctic (image credit: DLR)
Figure 11: Location of the Neumayer Station III on the Ekström ice shelf in Antarctica at 70°40'S, 8°16'W (image credit: AWI) 8)
Figure 12: Photo of the Neumayer Station III in Antarctica (image credit: AWI, Thomas Steuer)
The EDEN ISS Rack-Like Plant Growth Facility
The goal of the EDEN ISS Horizon2020 project is to advance controlled environment agriculture technologies beyond the state-of-the-art through demonstration in laboratory and analog environment. The main task of TAS-I (Thales Alenia Space -Italia) within the consortium led by the DLR Institute of Space Systems in Bremen is to develop a rack-like facility targeting at short-term safe food production and operation on-board the ISS (International Space Station), as the next step to past and currently on-orbit operated systems (e.g. NASA Veggie).9)
The EDEN ISS MTF (Mobile Test Facility) is being designed to provide fresh produce for overwintering crews at the Neumayer III Antarctic station, as well as to advance the readiness of a number of plant growth technologies [including the ISPR (International Standard Payload Rack) plant cultivation system demonstrator] and operational procedures. The MTF will be located approximately 200 m south from the Neumayer Station III Antarctic research station (Figure 13).
Figure 13: Area map of the Neumayer III station, including the proposed position of the EDEN ISS greenhouse (image credit: EDEN ISS Team)
The actual MTF consists of two 20 foot high cube containers, which will be placed on top of an external platform. The MTF is subdivided into three distinct sections, as shown in Figure 14:
• Cold porch: a small room providing storage and acting as a buffer to prevent the entry of cold air into the plant cultivation and main working areas when the main entrance door of the facility is utilized.
• Service Section: houses the primary control, air management, thermal control, and nutrient delivery systems of the MTF as well as the ISPR plant growth demonstrator.
• FEG (Future Exploration Greenhouse): the main plant growth area of the MTF, consisting of multilevel plant growth racks operating in a precisely controlled environment.
Figure 14: Overview of the EDEN ISS MTF main elements (image credit: EDEN ISS Team)
Most of the subsystems are housed in a rack system along the South-facing side of the Service Section (Figure 15). It was decided to place the ISPR as close to the cold porch as possible, since there are no interfaces between the ISPR and the FEG, as opposed to the other subsystems which do interface with the FEG.
Figure 15: Service Section cut view with ISPR – south side (image credit: EDEN ISS Team)
Atmosphere Management Subsystem and Thermal Control Subsystem: Each growth volume will have an independent air management system. The air management system will include:
• Temperature and humidity control system (THC)
• Major constituents control system (MCCS), managing the environmental pressure, as well as O2 and CO2 concentration
• Trace contaminants and microbiological control system (TCCS), removing organic gaseous contaminants (i.e. ethylene) as well as filtering out microbes and viruses.
The air management system has been primarily designed in order to be easily accessible and maintainable. Further upgrade of the selected technologies is also possible in this way. The overall system preliminary block diagram is reported in Figure 16.
Figure 16: Overall air management system conceptual block diagram (image credit: EDEN ISS Team)
NDS (Nutrient Delivery Subsystem): NDS is divided among multiple modules (ISPR drawers):
• The nutrient storage and distribution module/drawer, containing the reservoirs (stock solutions, acid/base, DI (Deionization) water, nutrient solution), the delivery pumps and the UV-C condensate bactericidal system
• The root module within each growth chamber module/drawer, containing the growth substrate, its container and the sensors and actuators needed to guarantee appropriate distribution of water and nutrient solution within the different area of the substrate.
Figure 17: Nutrient storage and distribution module/drawer (left); root module (right), image credit: EDEN ISS Team
The NDS block diagram is reported in Figure 18. Either DI water or nutrient solution can be delivered to the root modules. The block diagram is explained as follows.
Nutrient storage and distribution: DI water is used in case of salt accumulation within the root module (EC increment within the substrate or porous elements cleaning to prevent clogging). The DI water pH will be monitored and controlled by acid/base injection. The nutrient solution EC and pH will be monitored and controlled by water or stock solution (from dedicated reservoirs) injection. Injection will be allowed by LabVIEW® controlled piston pumps. Concentrated solution tanks will be flexible, replaceable (self-locking QD), stored dry and filled with water only before use. Water and nutrient reservoirs current baseline solution is a bellow tank. A solution for preparation of concentrate nutrient solution from dry nutrients possibly compatible with a microgravity environment will be tested.
Water recovery: Condensate recovered from the THC will be disinfected with UVC-LEDs and then passed through a membrane contactor (gas trap) to separate the air from the water flow.
Root module: Particular attention is given to the root module. Porous stainless steel plates are used for nutrient solution distribution and reclamation (in case of over watering) throughout multiple (4) substrate pillows. The plates are passivated to favor priming of the pores. Substrate moisture, EC and temperature are monitored via sensors connected to a common data downlink port. Three moisture sensors per pillow will be used. The substrate pillows reusability will be investigated (at least two growth cycles), as well as proper maintenance procedures developed for the Neumayer testing phase to be applicable to operation on ISS. EC will be monitored powering only one sensor each time, to prevent interference. — Electro-valves (or pneumatic valves), connected to a common power bus, regulate the water flow (with a single outlet and inlet per each root module) through the multiple porous plates.
Figure 18: Nutrient Delivery System conceptual block diagram (image credit: EDEN ISS Team)
C&DH (Command and Data Handling) Subsystem: The C&DH subsystem is housed in the Power, Command and Data Handling module/drawer (Figure 19).
Figure 19: Power, C&DH module/drawer (image credit: EDEN ISS Team)
The general conceptual schematic of the C&DH subsystem is given in Figure 20. Data are collected from the P/L drawer sensors into a NI Compact DAQ (cDAQ) board via dedicated I/O modules. Commands are generated by feedback control implemented within the cDAQ controller, and transferred to power relays via internal Digital Output (DO) modules. The different programs can be loaded onto the cDAQ board via rack-external signal, generated by a LabVIEW based computer and transmitted by LAN interface. The same interface is used for telemetry downlink.
Figure 20: Conceptional view of the C&DH subsystem (image credit: EDEN ISS Team)
PDCS (Power Distribution and Control Subsystem): Power will be delivered from the MTF to the ISPR via 230 VAC, 10 A electrical IF (230 VAC connector –plug - characteristics to be identified by DLR). 230 VAC to 24 VDC conversion will be provided within the ISPR volume, under the responsibility of TAS-I. DLR shall provide AC/DC converters models eventually used in the FEG, in an effort to increase commonality and have common spare parts. — The power will be then distributed to the different utilities via the commanded relays placed in the Command and Data Handling module/drawer (Figure 19). Moreover, manual override of key utilities (i.e. illumination, irrigation) on/off conditions will be possible, especially to favor maintenance.
Figure 21: Conceptual view of the PDCS (image credit: EDEN ISS Team)
ISPR Preliminary Crop Selection
The limitations on crop cultivation, in terms of available cultivation area within the ISPR and the limited Antarctic campaign duration, require selecting only a number of crops suggested for space life support systems. Researchers from Wageningen University and Research (WUR), experts in terrestrial greenhouse cultivation, developed a crop selection methodology. However, also peculiar interests of the project partners were considered based on space-related experiments heritage (analogy with current NASA Veggie testing as well as Italian heritage of Rucola on-orbit testing). The result is the following crop list:
• Dwarf Tomato (cultivar 2011-281M, F1 1202 or F12414)
• Rucula (cultivated, cultivar to be selected)
• Chinese cabbage Tokyo Bekana
• Outredgeous lettuce.
The selected crops will be grown in climate rooms at Wageningen University starting in early 2016. Initially, growth experiments will be conducted in order to define the optimal light recipes (spectral quality, light intensity and duration), as well as to optimize water and nutrient use. Afterwards specific experiments will be performed under similar conditions (size and constraints) as in the ISPR in order to test the cultivation and management of (combinations of) crops. The main features of the experiments will entail the determination of light recipes, optimizing CO2 dosage in accordance to plant growth rates, and relative humidity and temperature in relation to the light system being used. I/O flows (energy and mass) will be monitored throughout the experiments. A monitoring protocol will be defined to determine whether the crops grow as desired.
Status of the EDEN ISS project
• April 5, 2018: While the temperatures in the Antarctic gradually drop below 20 ºC and the Sun barely rises above the horizon, the plants being cultivated in the experimental greenhouse EDEN ISS are growing and thriving. After the first three weeks, Paul Zabel from the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR) has, over the last few days, harvested the first crops in the cold environment. The first harvest produced 3.6 kg of lettuce, 70 radishes and 18 cucumbers. What is now destined to enrich the diet of the overwintering crew demonstrates how astronauts on future Moon and Mars missions could be supplied with fresh produce. 10)
Figure 22: DLR researcher Paul Zabel holds a freshly harvested Antarctic lettuce in his hands (image credit: DLR)
- "Once I had finished sowing in mid-February, I struggled with a few unexpected difficulties, such as minor system failures and the fiercest storm of the last year," explains Zabel, an engineer and Antarctic gardener from the DLR Institute of Space Systems. "Thankfully, I was able to fix all the problems and survive the ordeal." Project Manager Daniel Schubert adds: "We have learned a lot about self-contained plant cultivation in recent weeks, and it has become evident that the Antarctic is an ideal test environment for our research." Now all the planned plants are growing in the greenhouse, including radishes, various types of lettuce, tomatoes, cucumbers, peppers and herbs (basil, parsley, chives and coriander). "The cultivation of strawberries is the only thing that we have not yet started," says Schubert. "We are still waiting for a successful sowing." The DLR researchers expect the container greenhouse to be operating at full capacity in May. They will then be able to harvest four to five kilograms of fresh vegetables each week.
- A 10-strong overwintering crew is currently living in the Alfred Wegener Institute's Neumayer Station III. The fresh vegetables they received with the last delivery at the end of February have all been consumed, so the residents are happy with the new additions to their menu. "Seeing our first fresh Antarctic salad was a truly special moment," says station manager Bernhard Gropp. "It tasted like it had just been harvested from the garden."
- Currently, Zabel spends three to four hours per day tending to the plants in the greenhouse, which is situated approximately 400 m from Neumayer Station III. He is mainly occupied with checking the technical systems and typical gardening activities such as pruning the plants. Meanwhile, he is in regular contact with the control center at the DLR Institute of Space Systems in Bremen, which is monitoring the plant cultivation remotely. On particularly stormy days, for instance recently on 21 March, Daniel Schubert and his team, Matthew Bamsey and Conrad Zeidler, are solely responsible for monitoring the greenhouse from Bremen until Paul Zabel is able to make his way from the station. This temporary measure can be maintained for up to three days.
- The EDEN ISS project will be conducted during an overwintering mission at the German Antarctic station Neumayer III, in collaboration with the Alfred Wegener Institute, Helmholtz Center for Polar and Marine Research (AWI). A large number of other international partners are contributing to a research consortium under the auspices of DLR, ensuring that the greenhouse will work smoothly in the Antarctic: Wageningen University and Research (Netherlands), Airbus Defence and Space (Germany), LIQUIFER (Austria), the National Research Council (Italy), the University of Guelph (Canada), Enginsoft (Italy), Thales Alenia Space (Italy), Arescosmo (Italy), Heliospectra (Sweden), the Limerick Institute of Technology (Ireland), Telespazio (Italy), and the University of Florida (USA) all form part of the consortium of the EDEN ISS project. The project is financed with funds from the EU Framework Program for Research and Innovation under project number 636501.
• February 20, 2018: The time has come: the EDEN ISS laboratory in the Antarctic has been set up, the first seedlings have been placed in the growth cabinets, and after eight weeks, the majority of the DLR (German Aerospace Center) team has returned to Germany. For DLR scientist Paul Zabel the only member of the EDEN ISS team to remain in the Antarctic until the end of 2018, this means that his winter deployment on the Neumayer III station operated by the Alfred Wegener Institute (AWI) has begun. Cucumbers, tomatoes and peppers will be the first home-grown crops at the world's southernmost tip. "Our aim is that there will always be something to harvest over the coming months," says DLR Project Manager, Daniel Schubert. After all, the harvest is intended to replenish the diet of the 10-person winter crew.11)
Figure 23: The EDEN ISS construction team says good bye to Antarctica (image credit: DLR)
The last few weeks have been busy for the scientists and engineers who assembled a working greenhouse on the eternal Antarctic ice from the container parts supplied. Temperatures of minus five to minus 10 degrees Celsius, coupled with strong winds, made their work much more strenuous than in their native Bremen, where the EDEN ISS laboratory was first tested. And these temperatures are set to drop significantly over the coming weeks. But in addition to the adverse weather conditions, the isolated location, which makes the delivery of fresh food impossible, also resembles the scenario of a mission to Mars, for example. Paul Zabel, together with nine other winter hermits, will live in the Antarctic station over the coming months – during a space mission, the team would be just as small. "And this is exactly what we aim to test – we want our greenhouse to produce 'space' tomatoes, lettuce and the like under realistic environmental conditions in such surroundings," says Daniel Schubert from the DLR Institute of Space Systems.
From basil to lemon balm: In addition to tomatoes, cucumbers and strawberries, the scientists are also planting lettuce, rocket, radishes, peppers, basil, chives, parsley, lemon balm and mint. The plants are irradiated with artificial light. Instead of soil, which would not be present during a long-term mission in a spaceship, for example, a nutrient solution fortifies the cultivated vegetables and herbs. The water in this closed-loop system is recycled – and only leaves the container in the harvested food.
"All the subsystems such as lighting, irrigation, air circulation and cameras have been tested and work perfectly". However, the harsh environment around the greenhouse has resulted in a few problems: for instance, the researchers had to find a solution when condensation formed in their container. "It makes a difference whether the container is in a city or in the Antarctic," emphasizes Schubert. Setting up the laboratory alone was laborious. If a tool was missing, for example, they had to return to the Neumayer station 400 m away to fetch it. Not only did all this result in a stressful time for the DLR team – it also provided a wealth of experience required for a subsequent space mission.
Living and working on the eternal ice: By the evening, explains Schubert, you were already exhausted. The DLR researchers had to get used to working in the laboratory, the extremely dry and icy Antarctic air, living in a confined space on the station with a total of 50 scientists and station crew and the four-bed rooms with shared bathrooms in the corridor. At this time of year, the Sun barely rises above the horizon before disappearing again an hour later at sunset. "You lose all sense of time and only know what day it is by what there is for lunch," says Schubert. "On Friday there is fish and Monday is pizza day." The scientists were also repeatedly visited by penguins curiously approaching the container and observing their work.
Harvesting in the Antarctic: Before Paul Zabel stayed behind as a ‘harvester' in the greenhouse, he underwent training courses and received some final instructions: how do the various subsystems work? Which plants need which care? He is now solely responsible for vegetable cultivation in the Antarctic: "I'm excited about this challenge," says Zabel. "It is similar to what astronauts will be doing on other planets in the future: I will think about home a lot. But at least I have got something green to look at here in the greenhouse in the Antarctic. And of course I am rather sad that I will not be able to see my family and friends for many months." The rest of the team will remain in contact with him via a video link and telephone. While Paul Zabel is now tending the first plants to grow in the Antarctic, his DLR colleagues are watching from the mission control center in Bremen, from where the participating researchers are actively involved and supporting the winter hermit.
Figure 24: The EDEN ISS laboratory commences operation as a greenhouse in Antarctica. Cucumbers, tomatoes and peppers will be the first home-grown crops at the world's southernmost tip (image credit: DLR)
Figure 25: DLR scientist Paul Zabel will remain in Antarctica until the end of 2018, supported by the project team from the control room at DLR Bremen (image credit: DLR)
1) Paul Zabel, Matthew Bamsey, Conrad Zeidler, Vincent Vrakking, Bernd-Wolfgang Johannes, Petra Rettberg, Daniel Schubert, Oliver Romberg, Barbara Imhof, Robert Davenport, Waltraut Hoheneder, René Waclavicek, Chris Gilbert, Molly Hogle, Alberto Battistelli, Walter Stefanoni, Stefano Moscatello, Simona Proietti, Guglielmo Santi, Filomena Nazzaro, Florinda Fratianni, Raffaele Coppola, Mike Dixon, Mike Stasiak, Eberhard Kohlberg, Dirk Mengedoht, Viktor Fetter, Thomas Hummel, Giorgio Boscheri, Federico Massobrio, Matteo Lamantea, Cesare Lobascio, Alessandro Petrini, Marco Adami, Giuseppe Bonzano, Lorenzo Fiore, Tom Dueck, Cecilia Stanghellini, Grazyna Bochenek, Anthony Gilley, Michelle McKeon-Bennett, Gary Stutte, Tracey Larkin, Siobhan Moane, Patrick Murray, Peter Downey, Raimondo Fortezza, Antonio Ceriello, "Introducing EDEN ISS - A European project on advancing plant cultivation technologies and operations," 45th International Conference on Environmental Systems ICES-2015-58, 12-16 July 2015, Bellevue, Washington, URL: http://elib.dlr.de/97937/1/ME-SBA-2015-Zabel-Rettberg-Introducing%20EDEN%20ISS-ICES.pdf
3) Paul Zabel; Daniel Schubert; Matthew Bamsey, " Ground Demonstration of Plant Cultivation Technologies and Operation in Space For Safe Food Production on-board ISS and Future Human Space Exploration Vehicles and Planetary Outposts," EDEN ISS - Executive Summary 12/2014, URL: https://zenodo.org/record/29670/files/EDEN_ISS_Exec_Summary_-_Rev0.pdf
4) Peter Convey, "Antarctic terrestrial biodiversity in a changing world," Polar Biology, Vol. 34, No. 11, 2011, pp. 1629–1641, URL of abstract: https://link.springer.com/article/10.1007%2Fs00300-011-1068-0
5) "University of Florida joins project team," EDEN ISS, 7 July 2016, URL: http://eden-iss.net/index.php/2016/07/07/university-of-florida-joins-project-team/
6) "EDEN ISS greenhouse en route to Antarctica," DLR, 10 October 2017, URL: http://www.dlr.de/dlr/en/desktopdefault.aspx/tabid-10081/151_read-24518/#/gallery/28752
7) "Arrival on the eternal ice - EDEN ISS greenhouse reaches the Antarctic," DLR, 11 January, 2018, URL: http://www.dlr.de/dlr/presse/en/desktopdefault.aspx
9) Giorgio Boscheri, Vincenzo Guarnieri, Ilaria Locantore, Matteo Lamantea, Cesare. Lobascio, Christian Iacopini, Daniel Schubert, "The EDEN ISS Rack-Like Plant Growth Facility," 46th ICES (International Conference on Environmental Systems), 10-14 July 2016, Vienna, Austria, URL: https://zenodo.org/record/60431/files/ICES_2016_351.pdf
10) "First harvest in the Antarctic greenhouse EDEN ISS," DLR, 5 April 2018, URL: http://www.dlr.de/dlr/en/desktopdefault.aspx/
11) "Crop cultivation begins in the EDEN ISS Antarctic laboratory," DLR, 20 February 2018, URL: http://www.dlr.de/dlr/en/desktopdefault.aspx/tabid-
The information compiled and edited in this article was provided by Herbert J. Kramer from his documentation of: "Observation of the Earth and Its Environment: Survey of Missions and Sensors" (Springer Verlag) as well as many other sources after the publication of the 4th edition in 2002. - Comments and corrections to this article are always welcome for further updates (firstname.lastname@example.org).