It would be possible to build (in orbit) a spacecraft to travel to another star, even if it would be the children or grandchildren of the crew who would finish the journey. It would require a large portion of the resources of the entire world, both economically and intellectually, and it would require them for generations. That seems more than a little unlikely.
"Rightful liberty is unobstructed action according to our will, within limits drawn by the equal rights of others. I do not add "within the limits of the law', because law if often but the tyrant's will, and always so when it violates the rights of the individual."-Thomas Jefferson.