For interstellar travel, time dilation could present both advantages and disadvantages. Depending on the goals of that travel, both aspects might apply to the same type of voyage. “Time dilation” refers to differing rates of speed at which two items travel, including objects and living creatures.

In reference to interstellar travel from Earth, the comparison would be applied to humans living on Earth and a spaceship and its human crew. Because the ship would be moving at light speed, time would pass more slowly for the crew members than for people back on Earth. Although the ship would seem to be gone for years as measured on Earth, time would pass much more slowly for those on board. As a result, they would age very slowly. A resulting advantage would be that the same crew could work for the flight’s entire duration. Disadvantages would be inevitable and possible changes on Earth, where the project personnel would age and would have to be replaced. Because technology would probably change, the sponsoring group would have to ensure that those changes did not impede the ship’s functions.