Tesla Inc. CEO Elon Musk’s SpaceX has secured three more commercial crew flights to the International Space Station as part of its contract with NASA, the U.S. space agency said on Friday. The additional crew flights would allow the U.S. space agency NASA to maintain an uninterrupted human access to the space station every now and then. The fresh contract to SpaceX comes after Boeing Co.’s delayed certificates for the Starliner spacecraft due to technical issues. “NASA anticipates a potential need to use any additional flights as early as 2023 to maintain mission readiness,” the U.S. space agency said in a blog post. Boeing may not fly astronauts for NASA until 2023—more than three years behind schedule. Boeing’s Starliner spaceship is grounded for the rest of the year due to hardware issues. NASA said it still plans to alternate missions between SpaceX and Boeing, once both are operational. “Securing additional …