This orbital mission will simulate and test two greenhouses that could be scaled up and assembled inside a lunar or Martian habitat to provide the crew with a local source of fresh food, while recycling human urine into fertiliser. Some microorganisms will be added to convert synthetic urine into easily digestible fertilisers for the tomatoes. The aim is to develop a stable, closed-loop, bio-regenerative life support system functioning in low gravity. In more detail, porous lava stones will be fitted in trickle filters and dried soil containing normal soil microbial colonies. Microbes then use nitrite to convert the harmful ammonia into nitrate, which is then added to six tomato seeds as liquid fertiliser. In addition, the system incorporates a colony of the single-cell microorganism Euglena gracilis, which is a photosynthetic algae able to produce oxygen and biomass while protecting the whole system against high ammonia concentrations. This oxygen is necessary for the conversion of urine to nitrate until the photosynthetic oxygen production by the tomatoes is sufficient. Initially, the spacecraft will replicate lunar gravity on one greenhouse for a period of six months before simulating Martian gravity on the second greenhouse for the next six months. The level of gravity on the Moon and Mars are simulated by rotating the spacecraft's cylindrical body around its longitudinal axis. The experiments on different payloads are realized in different positions within the cylinder. Tomato seeds will germinate and plant growth will be monitored with 16 cameras, while radiometers called RAMIS will monitor the radiation inside and outside the spacecraft. The greenhouse is made of clear polycarbonate, with an approximate volume of . The closed system features moisture, pH, oxygen, pressure and temperature sensors, and is capable to control these parameters. Four small fans create airflow through a cooling device to maintain a stable "atmospheric" temperature. On top of the greenhouse, three lamps provide light in the correct spectrum for photosynthesis. Scanners and fluorometers measure cell density and photosynthetic yield. The fluids are monitored with seven electrodes to measure ammonium, nitrite, nitrate, pH, chloride, sodium, and potassium. To monitor the health of Euglena gracilis, the system also analyse the microbes' mRNA to determine which proteins —and therefore which genes— are being commanded into action.
Objectives
The aim is to develop a stable, and symbiotic biological life support system while being exposed to gravity levels similar to those on the lunar surface as well as the surface of Mars. Both phases of experimentation will last for six months. With water being the only component that has been recycled so far and all other components being extracted and disposed, processing of urine is an issue in human space flight. Eu:CROPIS is intended to examine the possibility of using not only water, but also previously disposed waste to grow fruits and vegetables after proper conversion. Two life support systems within the satellite will be used for producing biomass out of artificial urine in a closed system. Furthermore, the algae Euglena gracilis will protect the biosystem against high levels of ammonia present in urine.
Supporting science payloads
PowerCell will investigate the performance of microbial mini-ecologies. These will contain the carbohydrate products of photosynthesis, which will feed Bacillus subtilis, a robust bacterium commonly found in soil and the gut, which has already proven that it can withstand the rigors of space while in the spore form. A second objective of the PowerCell Payload is to conduct synthetic biology remotely in outer space. The basic technique for introducing genetic material into a living cell, called transformation, involves the transfer across a cells encasing membrane of genetic material. The PowerCell payload will examine if and how reduced gravity levels affect transformation processes. The third objective is to test protein production under different gravity regimes. Using the tools of synthetic biology, B. subtilis was engineered to produce several proteins which will be produced at the three different space gravity regimes. The ability to make proteins in space will be fundamental for human exploration, as proteins will be used to produce a range of critical substances, from on-demand food and vaccines to building materials.
Radiation Measurement in Space has the goal of collecting data on long-term exposure to cosmic radiation over the course of the space flight
SCORE is a technology demonstrator for next generation on-board computing in hardware and software developed by the DLR Institute of Space Systems. It is complemented by a set of three cameras that are commanded via SCORE.
Satellite characteristics
Both the satellite and the experiment are called Eu:CROPIS. The satellite features four gyroscopes, two magnetometers, three magnetic torque rods and a sun sensor in combination with a single-frequency Phoenix GPS receiver for attitude control. The power for the satellite is provided by an Electrical Power Subsystem, which includes a lithium-ion battery and four deployable fixed solar arrays delivering an average of 520 W of power.
