Nasa says it's on track to launch its Artemis II mission in early April, which will see astronauts fly around the Moon for the first time in more than 50 years. The rocket had been set to blast off in March, but after a helium leak was discovered it was returned to the Vehicle Assembly Building in Cape Canaveral, Florida, for repairs. Nasa says it's confident the problem is fixed, and is planning to roll the rocket back out to the launchpad on 19 March, with the earliest possible launch date of 1 April.