Mars has two natural satellites: Deimos and Phobos; the latter orbits Mars closer than any other moon orbiting the other planets in the solar system, and it’s currently undergoing a process known as orbital decay.
In short, this means that Phobos is slowly drifting closer to Mars over time. Perhaps unsurprisingly, this has an impact on the gravitational pull between Mars and Phobos. As this tug strengthens, the tidal forces exerted on Phobos are increased, and this quite literally tears the moon apart.
Phobos’ surface is covered in strange lines, and according to planetary scientists, these are ‘stretch marks’ that result from the tidal forces that are being exerted on the moon as it orbits Mars. If the moon’s orbital decay continues at its current rate, then the moon could be destroyed in the next several million years, resulting in a planetary ring around Mars.
This raises the question: could we save Phobos from a seemingly inevitable demise? Theoretically, we could, but it wouldn’t be easy or practical.
At just 22 kilometers across, Phobos would be a lot easier to manipulate with thrust than some other moons in the solar system. The science indicates that a thruster nearly as large as the Empire State Building filled with rocket fuel would be required to achieve this feat, and as you might come to expect, this would be incredibly expensive and wasteful of limited resources.
Perhaps the best thing to do is just to let nature take its course and allow Phobos to break apart.
