31 March 2017 Last updated at 09:06 BST
This rocket launch is no ordinary lift-off.
It's the first time a rocket's headed back into space after having been there once before.
Normally rocket parts are used only once and then scrapped or destroyed when it lands back on Earth.
But American company SpaceX has found a way of landing rocket parts safely back on Earth and then re-using them to head back into space.
This rocket was recovered at sea from its first flight in 2016.
The main section of this then landed back onto a floating platform in the ocean, which would enable its recovery for a possible THIRD mission.
By reusing rockets, SpaceX aims to send make space travel much cheaper.