Maybe one or two remember, that we recently announced a uncommon CubeSat mission idea. A friendly German fellow gave us the helpful advice to use tardigrades instead of unicellular organisms like slipper animalcule. Tardigrades are commonly known as water bears or moss piglets:

Water bears are very resistant. They can withstand very low and high pressure and temperature, radiation doses of 5000 Gy and are able to survive nearly 10 years in a dry state. AND they have already space experience.

A first design sketch for an experiment set-up to study the behavior of the water bears in space live via video stream appears in the image below:

The water bears shall be launched in try state and only then supplied with growth medium in low Earth orbit. The oxygen supply could be done by a small oxygen container, a separate oxygen chamber with exchange membrane or unicellular algae in the growth medium by photosynthesis.