The biggest zero-gravity lab is of course the International Space Station (ISS), where studies of plant growth, crystal growth and physical science phenomena are commonplace. At any one time 300 experiments are taking place on the ISS.
Turning a benchtop experiment into a self-contained science payload for space is not easy. Each one must be rigorously tested before launch to make sure it will work once it gets there, using parabolic flights or other testing platforms.
Going ‘zero-g’
There’s a common misconception that you have to go into space to experience microgravity. In fact, it’s the condition of freefall that makes things apparently weightless and that can be experienced here on Earth too.
If you throw a ball to a friend, it traces an arc as it flies through the air. From the moment it leaves your hand it’s in freefall – yes, even on the way up – and this is the exact same arc that the aircraft flies. Instead of a hand, it has an engine providing the “push” it needs to travel and fall through the air, tracing out a parabolic arc as it goes.
Even the International Space Station is experiencing the very same freefall as the ball or the aircraft. The only difference for the ISS is it has enough velocity to “miss the ground” and keep going forwards. The combination of the forward velocity and the pull towards Earth keep it going around in circles, orbiting the planet.
Human spaceflight
Parabolic flights in the USA and Europe occur every two or three months. On the flights, researchers conduct science, companies test technologies and astronauts receive training in preparation for spaceflight missions.