How Long Mark Watney Was On Mars In The Martian

Here’s how much time Mark Watney, Matt Damon’s character in The Martian (2015), spent on Mars, and why it took so long for him to be rescued.

Mark Watney had to survive on Mars in The Martian (2015) for several days. Based on Andy Weir’s The Martian novel, Ridley Scott’s The Martian starred Matt Damon as Mark Watney. Set in a future where humans are beginning to colonize Mars, The Martian saw Mark Watney use every resource at his disposal to survive by himself and eventually return home.

Part of what makes The Martian one of the best Ridley Scott sci-fi movies is how Mark had to calculate every decision he made on Mars. Having to grow his own food and produce his own water, Mark could not miscalculate any move. Mark’s survival plan was based on waiting for the Ares IV mission to arrive on Mars and rescue him.

Mark Watney Was On Mars For 564 Days In The Martian

Mark Watney experienced 549 Martian days on Mars in The Martian. Considering that Mars has a larger orbit than Earth, Martian days are longer than Earth days. More precisely, it takes around 24 hours and 40 minutes for Mars to complete one rotation. Therefore, what Mark experienced as a day on Mars was actually 40 minutes longer than a day on Earth. That is why Mark had to register his journey using “sols,” the scientific term for Martian days. 549 sols on Mars equals 564 Earth days. To put numbers in perspective, Mark spent more than a year and a half on Mars.

The Martian’s timeline becomes easier to decipher by considering that the Ares III astronauts rescued their colleague on sol 549. Given that the Hermes originally left Mars on sol 18 of their mission, Mark spent 531 sols by himself on Mars. In other words, Mark Watney was left alone on Mars for 546 Earth days. Had NASA followed their initial plan of rescuing Mark during the Ares IV mission, Matt Damon’s character would have spent four years on Mars. Mark’s rescue mission in The Martian was risky, but it brought the botanist home way faster than originally planned.

Why Mark Watney Was Stranded On Mars For So Long

By the time NASA found out that Mark Watney was alive, it was already too late for the Hermes to go back. That is why Teddy Sanders (Jeff Daniels) decided not to tell the crew of the Hermes that their friend was alive. Teddy feared that the news would break the Ares III crew, which could put their return to Earth in danger. Mark’s only alternative seemed to wait four years on Mars until the Ares IV, Earth’s next mission to the red planet, landed. Mark’s crop production, however, could not keep him fed for four years. If Mark was to survive, NASA would have to send supplies.

That is why the agency planned to send a space probe, an unpiloted unity, with supplies ahead of the rescue mission. In that scenario, Mark would have enough food to survive for four years on Mars until the Ares IV arrived. However, thanks to Rich Purnell (Donald Glover), Mark’s rescue happened significantly faster. Rich suggested using the Taiyang Shen booster rocket to send supplies to the Hermes, and then using Earth’s gravitational field to put the Hermes on a route back to Mars. The Rich Purnell Maneuver was dangerous, but it worked. The Hermes returned to Mars and rescued Mark 564 Earth days after The Martian’s original mission began.