Sidereal Orbital Period of Mars
| Value | 59,355,072 s |
| Status | Conventional / typical value |
| Source | NASA NSSDC Planetary Fact Sheet, Mars (sidereal orbit period) |
| Categories | Astronomicalsolar-systemplanets |
| Planck time | 1.1009526e+51 tP |
| attosecond | 5.9355072e+25 as |
| femtosecond | 5.9355072e+22 fs |
| picosecond | 5.9355072e+19 ps |
| nanosecond | 5.9355072e+16 ns |
| shake | 5.9355072e+15 shake |
| microsecond | 59,355,072,000,000 μs |
| millisecond | 59,355,072,000 ms |
| second | 59,355,072 s |
| minute | 989,251.2 min |
| hour | 16,487.52 h |
| sidereal day | 688.86089 sd |
| day | 686.98 d |
| week | 98.14 wk |
| fortnight | 49.07 fn |
| month | 22.570648 mo |
| year | 1.8808487 yr |
| decade | 0.18808487 dec |
| century | 0.018808487 cent |
| millennium | 0.0018808487 mil |
| megayear | 0.0000018808487 Myr |
| eon | 1.8808487e-09 eon |
Learning zone
Mars takes 1.881 Earth years to circle the Sun, and the interplay of that period with Earth's produces the synodic cycle every mission planner lives by: Earth laps Mars once every 780 days, so the low-energy launch opportunities — when a spacecraft can coast a Hohmann half-ellipse and find Mars waiting at the far end — recur roughly every 26 months and last a few weeks. Miss one, as ESA's ExoMars rover did in 2020, and the next try is two years later.
The long year also doubles every season. With an axial tilt almost matching Earth's, Mars runs the same cycle of spring, summer, autumn and winter, but each lasts five to seven months — unequal because the eccentric orbit makes the planet linger near aphelion. A quarter of the atmosphere freezes onto the winter pole each year and sublimates back each spring, a breathing cycle the orbiters watch as a seasonal change in the planet's gravity field.