Let's ignore the moral perspective for the moment and think about the ship itself. A secure, life sustaining environment inside a space vehicle for such a long journey is not yet possible. Man reaching the moon was probably just a fluke. Alas, things did go wrong. Apart from the well known ballpoint pen in the circuit-breaker hole trick by Buzz Aldrin, there were dozens of problems that mysteriously were all solved - divine intervention? Well, we will never know.
A trip to Mars will be a chain of continuous problems. For a start we do not know what the real space environment is like out there. Astronauts could die of radiation in a few months of travel. There is no solution to this. Mechanical issues with the ship are almost certain. It may not be possible to go outside to make repairs.
Lastly, how will this end? if they do safely reach Mars they could either be filmed choking to death when the oxygen runs out, or being burned alive as the craft obits inward and falls to the planet itself. The easiest option it to bite down on a pill. Some, however, will not be able to do this.
✴ Science by Ty Buchanan ✴