The Yamato is sent on a trip to Iskendar, 183,000 light years away. Their goal is to reach Iskendar and return to Earth before a year has elapsed. Due to the distance from earth, this will require faster-than-light travel to make it back in time. However, taking into consideration of how fast they are travelling time dilation would cause their return to be thousands of years later, after the invasion has already completed and earth has been terraformed.
How can they make it to their destination and back within their one year deadline?