Some of the most inventive minds on Earth are thinking about how to colonize space. There are places in Earth’s orbit that might someday are used to launch human explorers into deep space, but there are also some people who want to make small pockets of air within our planet hospitable for human life. One possible solution is to turn a place, like the inside of an airplane, into an environment that feels like home by creating new microbes, such as versions of E. coli, that could live without oxygen for long periods.
The first step toward creating a true home in space is to create an environment with deficient oxygen levels. Most humans survive for only a few minutes without oxygen because the body uses its backup systems, such as anaerobic glycolysis, if no more air is available to breathe. After three minutes without air, the body begins to use energy from fat stores and builds up lactic acid that can damage neural tissue. After five minutes on a level with less than 2 percent oxygen, the lactic acid can cause problems like convulsions and death.
Scientists have already created a microbe called Deinococcus radiodurans that can survive in space. The microbe is so hard to kill that many scientists think it may be able to survive a nuclear explosion and be the first life form on Earth if human life on Earth is ever obliterated.
The second step toward creating an environment with low oxygen levels is to make the environment almost entirely devoid of water. It can happen naturally in the coldest regions of space, but a low-oxygen climate works too. Most people can survive for about a month if only 5 percent of their body is covered by water, and most people die if more than 25 percent of their body is made from water. The body can survive for months or years if the water is replaced with a nonliving solution.
Since there is an increasing amount of interest in sending humans to live on Mars, NASA researchers decided to take tiny droplets of water with living organisms into space and see what would happen. The idea was that these “cells in space” would not have as much water available, forcing them to adapt or die.
The researchers took a droplet of water filled with microbes and exposed it to outer space for 15 minutes. After 15 minutes, they brought the board back to Earth. The droplet’s moisture levels increased, but the water was still frozen. More importantly, the droplet was full of microbes that could survive 15 minutes in outer space.
The researchers also took a sample of microbes and exposed them to low-oxygen air for several hours. The microbes became resistant to low oxygen levels, and scientists could make new microbe mutants with these properties from DNA found in the cells after this process.
Suppose scientists can create an environment that uses bacteria or other microbes as the primary methods for producing oxygen. In that case, humans can colonize a space station and even live on a planet like Mars. If we develop microbes that can adapt to extreme environments, humans can survive in usually sterile places.
There are some issues with using microbe mutants who have only adapted to small amounts of oxygen for long missions into space because too much oxygen can be poisonous. However, NASA is planning experiments where astronauts will live in tiny containers filled with low-oxygen air or water to prepare them to live on Mars one day. It might be possible for humans to live on Mars as early as 2030.
A faster way to colonize space could be through regenerative life support systems (BRS) that use algae instead of microbes. It would allow humans to survive in places like the International Space Station without having to wait for them to develop microbe mutants that can live away from oxygen forever. Researchers have developed BRS that can produce oxygen using algae and carbon dioxide, but they are still costly and have yet to be flown into space to see if they work in practice.
Once these new mutant colonies are grown, they can be applied to new environments with reduced oxygen levels or used for other research about how humans can adapt to different settings on Earth or in space.
