Space environment had a few more constraints, mainly gravity reduction and space radiations.
Gravity will mainly affect the multi-phase issues: Gas/Liquid/Solid mixing and/orseparation. Radiations potentially affect the molecular level of the bacteria (e.g. DNA, RNA).
Within MELiSSA project two flight experiments (BISTRO and NITRIMEL) have been successfully performed. Two more are currently under preparation. The first two experiments demonstrated the reactivation potential of a microbial consortium, when exposed to elevated levels of radiation and fluctuating gravity. These findings are promising for all nitrification-based processes.