What Are Some of the Challenges of Growing Plants in Space?

We’ve created a new page, Challenges of the Voidwhich explores the factors of space that impact plant biology.  Check it out!  It’s in the lab. Here is what it entails so far.

Surviving a Space Environment

One of humanity’s greatest shifts was a switch from hunter-gatherer clans to an agrarian type society. By becoming stewards of the land we had everything to gain.  The first era of agriculture paved the way for stability and sustenance that gave rise to the first ancient civilizations.  Another era of agriculture is soon to be upon us: we must grow plants in space. Successful cultivation of plants in spaceflight environments will be a key step for the first space civilizations. Just as our ancestors learned to grow crops, we will do the same: in space.

What is a spaceflight environment/where will we grow our plants in space?

Clearly, plants cannot grow or survive in the vacuum of space.  There is no oxygen, no defense, very little gravity, and no opportunity for nutrient uptake.  Growing plants in human spaceflight systems such as a shuttle or aboard the International Space Station helps take care of a few of these issues right off the bat.  Firstly, human spaceflight systems provide oxygen for its inhabitants and can for plants as well.  Secondly, spaceflight systems are shelters that can physically shield inhabitants from solar radiation.  The things that we cannot yet protect our plants from are the effects of microgravity, ionizing radiation and intense oxidative stress.

Microgravity

Many people believe that space is a zero gravity environment and that a lack of gravity causes weightlessness.  This is a common misconception.  The truth is gravity is present everywhere in space.  Everything in the universe is falling and is affected by gravity.  The orbit of the International Space Station is due to gravity.  Using the term zero gravity is misleading.  Zero gravity implies zero acceleration which is not true because the ISS is constantly accelerating towards Earth.  A more scientifically accurate term would be microgravity.  Microgravity is really micro-acceleration and astronauts appear weightless because the effect of gravity grows weaker with increased distance from a large planetary body.

Ionizing Radiation/Galactic Cosmic Rays

Galactic Cosmic Rays are a type of ionizing radiation that is difficult to defend against.  Protons (and other heavier elements) are accelerated to the speed of light after blasting off from exploding stars. This strong radiation bombards organisms and damages molecular structure.  Unlike solar radiation, GCRs are difficult to defend against physically.  The Earth generates a magnetic field that can deflect this radiation to keep our planet safe.  This strength comes from sheer size.  Obviously a spacecraft is much, much, much smaller than a planet so it cannot generate a magnetic field that strong.  This secondary radiation poses a huge health problem for astronauts as well as plants.