Render of the Eu:CROPIS satellite after launch
|Mission type||Life sciences research|
|Operator||German Aerospace Center|
|Mission duration||Planned: 1 year |
|Bus||DLR Compact Satellite bus|
|Launch mass||250 kg (550 lb)|
|Dimensions||1.0 m diameter x 1.13 m length|
with panels deployed: 2.88 m wide
|Power||520 W, 4 solar arrays, Li-ion batteries|
|Start of mission|
|Launch date||3 December 2018|
|Rocket||Falcon 9 (Block 5)|
|Launch site||Vandenberg Air Force Base|
|Regime||Low Earth (SSO)|
|Perigee altitude||575 km (357 mi)|
Eu:CROPIS (Euglena and Combined Regenerative Organic-Food Production in Space) is a life science satellite developed by the German Aerospace Center (DLR) and is intended to investigate the possibility of growing plants (specifically tomatoes) in different levels of gravity, such as on the Moon and Mars, as a sustainable food source while using human urine for moisture and as the source of fixed nitrogen.
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 (NO−
2) to convert the harmful ammonia (NH
3) into nitrate (NO−
3), 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 (0.16 g) and Mars (0.38 g) 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 (RAdiation Measurement In Space) will monitor the radiation inside and outside the spacecraft.
The greenhouse is made of clear polycarbonate, with an approximate volume of 12 L (730 in3). 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.
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 (a nitrifying trickle filter system and the single-celled algae Euglena gracilis) 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.
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.