SpaceX has called off the launch of the highly anticipated Polaris Dawn mission for the second day in a row but this time it has not set a new schedule. In a message posted on social media on Tuesday evening about five hours before a Falcon 9 rocket carrying four passengers was due to lift off from the Kennedy Space Center in Florida, the spaceflight company said it had made the decision due to a weather forecast that suggested there will be unfavourable conditions off the coast of Florida in five days’ time when the Crew Dragon spacecraft was due to splash down. It added that it will continue to assess the weather situation before deciding on a new launch schedule.