Want to know just how routine spaceflight has become? Just look at SpaceX's latest mission. The company is livestreaming the launch of its CRS-18 resupply mission for the ISS with an expected liftoff at 6:24PM Eastern, and every component from the mission is well-worn. The Falcon 9 launched a previous ISS supply mission in May, while the Dragon has visited the ISS twice -- once in April 2015 and again in December 2017. This is the first instance of SpaceX flying a Dragon capsule for the third time, the company said.