Higher Plant Characterization

Engineering, manufacturing and testing a new Plant Chamber Unit (PCU) for closed-loop life support systems.

Objectives

The Higher Plant Compartment is one of the most complex compartments in the MELiSSA loop, and studying, characterising and mathematically modelling plant development and crop production requires dedicated research infrastructure. The facility built for this purpose is known as the PaCMAN Unit: a unique, environmentally controlled and leak-proof system for scientific studies across a range of crops. Among other things, it enables detailed study of water transfer into, within and out of the plant, by allowing the aerial zone and the root zone to be examined separately.

Examining the PaCMAN Unit’s plant growth chamber under LED lighting.

Close characterisation of a crop under study at the PaCMAN Unit.

Challenges & Approach to the Research

Thanks to its multifunctional nature, the crop within the MELiSSA loop contributes to water recycling, air regeneration and food production, while also generating waste in the form of the non-edible part of the plant. These contributions vary considerably from crop to crop. Closing the MELiSSA loop therefore requires:

Careful selection of the crops.
Detailed knowledge of the dynamics of these functions.
Quantitative inputs and outputs at both the crop scale and the higher-plant-compartment scale.

Past work on this topic demonstrated the need for dedicated research infrastructure, for both crop studies and food-processing studies, and for well-defined research programmes. The PaCMAN Unit is paving the way for these research programmes.

Flight Experiments

In the absence of gravity, natural convection does not occur, so the gas and water exchanges that result from a plant’s physical processes are significantly affected.

Two microgravity experiments, ANTHEMS and WAPS, were conceived within the MELiSSA project to study this. ANTHEMS focuses on the transpiration process at the leaf level, that is, water leaving the plant, while WAPS focuses on the whole water transport system, into, within and out of the plant.

Open view of the ANTHEMS experiment hardware for parabolic flight.

ANTHEMS has flown twice on Novespace’s A310 ZERO-G aircraft, and WAPS is planned for accommodation on board the International Space Station.

Fine-tuning the WAPS experimental protocol in space-like hardware, ahead of the flight experiment on board the ISS.

Terrestrial Applications

The outputs of these space-related research programmes can also be applied to plant cultivation in extreme environments on Earth, within the broader goal of using resources more efficiently and achieving greater sustainability.

Vertical hydroponic cultivation, one terrestrial context this research also informs.

Education & Communication

STEM activities are promoted by hosting and supervising the next generation of researchers through the Doctoral Program, as well as through education projects such as MULTITROP and AstroPlant, an education kit for basic crop modelling.