The two biggest commercial space companies are stepping up.

Add Yahoo as a preferred source to see more of our stories on Google. The towering rocket that will help propel a group of astronauts on NASA's first human moon mission in half a century may soon be visible along Florida's Space Coast. In a matter of days ...

NASA’s first crewed moon mission in decades was delayed as its engineers grapple with an all-too-familiar rocket problem: hydrogen leaks. Fixing the issue is even trickier than it may seem.