the statement that humans could never return to Earth if they went to Mars is not entirely accurate. The feasibility of returning from Mars depends on various factors and the specific mission design.
If a manned mission were to be sent to Mars, it would likely be a complex and challenging endeavor. The astronauts would have to face significant risks and difficulties related to the long journey, life support systems, radiation exposure, landing on Mars, staying on the planet for a period, and then launching back off its surface to return to Earth.
One crucial consideration is the "return window" – the specific time when the Earth and Mars are positioned favorably for a return trip. This window occurs approximately every 26 months when Mars and Earth are in the right alignment for a relatively efficient journey. If a mission were to miss this window or encounter technical issues preventing the launch from Mars, the crew could be stranded for an extended period or indefinitely.
However, space agencies and private companies planning manned missions to Mars are well aware of these challenges. They are actively working on developing technologies and strategies to ensure safe return missions. For instance, SpaceX, with its Starship spacecraft, has expressed intentions to send people to Mars and back.
As technology progresses, we may see advancements that increase the likelihood of safe returns from Mars missions. Nevertheless, any manned journey to Mars would be a monumental undertaking with inherent risks and uncertainties. The goal is to make such missions as safe as possible for the astronauts involved.