Private American space companies Blue Origin and SpaceX are paving the way.

Blue Origin, which was created by Amazon CEO Jeff Bezos, successfully launched its "New Shepard" space vehicle for the first time on April 29. The vehicle was named after Alan Shepard, who became the second human and first American to enter space 44 years ago.

Two weeks earlier, on April 14, Elon musk's SpaceX attempted to land one of its Falcon 9 rockets on a floating platform in the Atlantic Ocean.

Both events were significant tests in the race to build a fleet of revolutionary reusable rockets. With such a fleet, companies could launch the same rocket many times over instead building rockets that they only use once and crash land in the ocean, which is common practice for many current space companies like Arianespace.