Chlorella vulgaris, the microalgae species selected for the Powerhouse-1 mission, was among the first lifeforms to evolve at the beginning of Earth’s history. By successfully converting methane and carbon dioxide into oxygen it helped create the right atmosphere for other lifeforms to evolve on our planet. It is now commonly used as a protein-rich food supplement, particularly popular in Japan.
The microalgae’s home-away-from-home aboard the International Space Station is a flask inside a specially engineered device, designed in collaboration with Western Sydney students, Powerhouse, Space Tango and Magnitude.io. Each school participating in the program is also using 10 ExoLabs for synchronous missions (control experiments) and ground trials. These ExoLabs use custom racks the students designed and produced with 3D printers.
Experiments conducted by Western Sydney students in the Powerhouse Future Space program comparing growth of Chlorella vulgaris in microgravity versus on Earth could provide answers to important scientific questions about its potential to positively change Earth’s climate once again — and benefit space exploration.
‘Our experiment is aimed at finding a sustainable way to produce algae or to make algae reproduce faster. Our hypothesis is that algae will hyper-reproduce in the microgravity of the ISS due to the lack of gravity,’ Powerhouse-1 mission team member Marko from Casula High School explained, adding that in the long term, oxygen-generating algae could help make Mars a green planet.
'It will be interesting to see how it grows in the near absence of gravity, when we lose things like convection,' said Ted Tagami. 'If your algae starts to grow, what does it do? It's heavier than water, so here on Earth it settles at the bottom. There's no settling in space, so what's going to happen to our algae in orbit? Is it going to cling to the sides? Is it going to clump together? Will it stay dispersed? It’ll be fascinating capturing images looking down on top of the vials. In the world we live in today, my view is that answers are no longer as valuable as the questions that are asked. A great question will open up more questions. That’s where curiosity gets engaged. That's where discovery happens. And that's where wonder happens.'
Back on Earth, the students have already conducted ground trial experiments guided by algae experts at the UTS BioTech Hub facility, followed by four phases of ground trials at their schools guided by Sophie Poisel, head of Lang Walker Family Academy, Powerhouse, Ben Newsome, director of Fizzics Education, and teachers at each school. These experiments revealed the ideal growing conditions for Chlorella vulgaris on Earth are 15 hours of very low intensity light (9.6 lumens), an average temperature of 25ºC and a medium which includes nutrients to support growth.
'During the ground trial experiments students analysed CO2 and humidity data and linked that data to the process of photosynthesis in plants,' said Franklin Lamin, iSTEM teacher, Arthur Phillip High School. 'The students drew a connection between the fluctuations shown in the data and the photoperiod (the period each day an organism is exposed to light) for their flasks and concluded that algae needs a longer photoperiod and lower light intensity for successful growth. Lower growth in unsuccessful flasks was linked to a shorter photoperiod. They also learnt that the successful flasks had lower light intensity compared to the unsuccessful ones.'
Students in the Powerhouse: Future Space program have also studied other potential uses for algae connected to sustainability, such as biofuels, medicines and nutrients for humans and plants alike. Other experiment ideas proposed for consideration included investigating how microgravity affects microbial resistance, honey production, grasshoppers, the development of insulin, the development of neurons and the growth of mould and Australian native plants.
