How does space give us oxygen?

Answer 1

The oxygen we use everyday in a breathable form is not normally found in space beyond our own atmosphere. The plant ecosystem here converts carbon dioxide to oxygen. NASA must transport large containers of air for the astronauts to breath on space missions. Over last few years NASA and other space agencies have started using oxygen generators, some of which convert water to oxygen. These devices are very expensive and not very efficient, but are improving over time.

Answer 2

Space itself does not produce oxygen. Oxygen is primarily produced on Earth through the process of photosynthesis by plants and algae, which convert carbon dioxide into oxygen using sunlight. Astronauts on space missions rely on oxygen supplies carried with them or generated through systems that produce oxygen from water.