Mars 2016: Season 1Last updated this post: 19 December, 2016 Mars Planet Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System, after Mercury. Radius: 3,390 km Gravity: 3.711 m/s² Length of day: 1d 0h 40m Mass: 6.39 × 10^23 kg (0.107 M⊕) Surface area: 144.8 million km² Moons: Phobos, Deimos EPISODE 1 2 3 4 5 6 18/18Dark Desire 2020: Season 1 6/6James May: Our Man in Japan 2020: Season 1 24/24The Big Bang Theory 2015: Season 9 7/9Murder Decoded 2019: Season 1