ELON MUSK: "The major breakthrough that SpaceX is hoping to achieve this year is full reusability. No one has ever achieved full reusability of a rocket, which is very important for the cost of access to space.

We've achieved partial re usability with Falcon 9. We've now landed the boost stage over 500 times, but we have to throw away the upper stage. The upper stage burns up on reentry and the cost of that is equivalent to a small to medium sized jet.

So with Starship, which is a giant rocket, it's the largest flying machine ever made, we should prove full reusability, which will be a profound invention, because the cost of access to space will drop by a factor of 100 when you achieve full reusability. So it makes putting large satellites into space very low, very cheap."