The concept of time dilation in space is a consequence of Einstein's theory of relativity. According to the theory of general relativity, time can be affected by gravity and relative motion. Therefore, the perception of time can change depending on the circumstances.
For astronauts in space, time dilation is indeed a factor to consider. However, the effect is relatively small unless they are traveling at speeds close to the speed of light or near extremely massive objects like black holes.
For astronauts aboard the International Space Station (ISS), which orbits Earth at an altitude of about 408 kilometers (254 miles), time dilation is not significant enough to have a noticeable effect. The difference in the passage of time between the ISS and Earth is on the order of microseconds or milliseconds over the course of a year.
However, if we consider long-duration space missions, such as interplanetary travel, where spacecraft can travel at significant fractions of the speed of light or spend extended periods near strong gravitational fields, then time dilation becomes more relevant. In these cases, the dilation effect can become more pronounced, resulting in a difference between the duration experienced by the astronauts and the time passing on Earth.
To provide a specific answer to your question, it would depend on the specific conditions of the space travel. Without more specific information, it's challenging to give an exact ratio of Earth years to space years.