Svetoblok was the first airtight, sterile growth chamber for spaceflight, and its experiments helped us understand that plants can develop flowers in space. This chamber was compact, with a small removable cylinder that could be returned to Earth independently of the chamber. To return the plants to Earth, cosmonauts simply held the removable cylinder in their laps on the trip down! Svetoblok was first flown in 1982 and was used on both the Salyut and the Mir space stations.
Svetoblok’s sterile environment was believed to be a big reason for its success. In 1982, cosmonauts successfully grew the first flowers in space from Arabidopsis, a tiny mustard species commonly used in research. Although these flowers bloomed and began to develop fruit, the male and female organs degenerated, so no viable seeds were produced. These plants developed abundant branches, though the leaves were smaller than ground controls, and the “leaf and shoot tissues had a finer structure and looked like aquatic plant shoots”. Although all of the buds, flowers, and fruits were sterile, some plants were returned to Earth and did eventually produce mature seeds. Other Svetoblok experiments were conducted with Arabidopsis and wheat, with similar results: flowers without viable seeds. Scientists concluded that low light and lack of gas flow were probably responsible for the plants’ inability to reproduce.
The success of flowering in Svetoblok demonstrated that the seed-to-seed life cycle should be possible in microgravity, given the right environmental conditions. Svetoblok was one of the key growth chambers that laid the groundwork for plant reproduction in space.
Chamber Components:
- Cylindrical, transparent plastic growth chamber (could be removed from the mounting bracket)
- The first version used cabin light, where the Svetoblok was designed to clip under a light on Salyut 6, and light intensity ranged from 2000 to 4000 lux. Fluorescent lamps were used in later versions.
- First version used a 1.5% agar-based nutrient delivery system, but other media was used in later versions. This updated media was watered through the action of the Oasis water delivery system.
References:
- Review and analysis of plant growth chambers and greenhouse modules for space
- Characterization of Physiological Changes in Roots Grown in Spaceflight Conditions: A Comparison of Nutrient Delivery Technologies
- “From Seed to Seed” Experiment with Wheat Plants Under Space-Flight Conditions
- Plant Reproductive Development during Spaceflight
- Peculiarities of genital organ formation in Arabidopsis thaliana (L) Heynh. under spaceflight conditions
- Spaceflight hardware for conducting plant growth experiments in space: The early years 1960–2000