Actually the 1000 year number comes from Project Orion in the 1940ties and 50ties. https://en.wikipedia.org/wiki/Project_Orion_(nuclear_propulsion) https://en.

Actually the 1000 year number comes from Project Orion in the 1940ties and 50ties. https://en.wikipedia.org/wiki/Project_Orion_(nuclear_propulsion) https://en.wikipedia.org/wiki/Project_Orion_(nuclear_propuls... An updated design from the 80ties calculated a time of 100 years: https://en.wikipedia.org/wiki/Project_Longshot https://en.wikipedia.org/wiki/Project_Longshot And a nuclear fusion design is calculated to achieve 12% of light speed, thereby reducing time to reach the fourth nearest sun system in 46 years. https://en.wikipedia.org/wiki/Project_Daedalus https://en.wikipedia.org/wiki/Project_Daedalus So there are concepts that could make unmanned interstellar travel possible, even within a humans life span, it's just that it costs so much and the incentive is pretty low compared to the incentive countries had for getting objects into space. (primarily military incentives - get spy satellites and nuclear warheads into space to not fall back behind adversaries) I believe that given a strong enough incentive humans could do it, no matter what current consensus is telling us. Humans set out to work on reaching outer space without even having a design on how this could be achieved and we did it anyway.