A better way would be to explode one medium sized nuke under the ship, wait a few seconds then explode another and then start exploding nukes behind it until it

A better way would be to explode one medium sized nuke under the ship, wait a few seconds then explode another and then start exploding nukes behind it until it's going fast enough. Project Orion did contemplate a 400m diameter ship weighing 8 million tons.... https://en.wikipedia.org/wiki/Project_Orion_(nuclear_propulsion) https://en.wikipedia.org/wiki/Project_Orion_(nuclear_propuls...