What if Country X starts building a starship in, say, 40 years and it works and off they go.
Then Country Y invests in new technology and starts building their new ship in, say, 100 years.
It's possible and likely that Country Y's starship is more capable and faster than Country X's ship as they would have waited for and capitalized on scientific breakthroughs that make interstellar travel better.
Then Country Y invests in new technology and starts building their new ship in, say, 100 years.
It's possible and likely that Country Y's starship is more capable and faster than Country X's ship as they would have waited for and capitalized on scientific breakthroughs that make interstellar travel better.