Formation and evolution of the Solar System leads to decreases in the magnitude of each (that cancel each other out). In both cases, tidal deceleration causes the moon to spiral in towards the primary until it either is torn apart by tidal stresses, potentially creating a planetary ring system, or crashes into the planet's surface or atmosphere. Such a fate awaits the moons Phobos of Mars (within 30 to 50 million years), Triton of Neptune (in 3.6 billion years), Metis and Adrastea of Jupiter, and at least 16 small satellites of Uranus and Neptune. Uranus's Desdemona may even collide with one of its neighboring moons. A third
Martian Moons Exploration Phobos, and land once or twice and gather sand-like regolith particles using a simple pneumatic system. The lander mission aims to retrieve a minimum of samples. The spacecraft will then take off from Phobos and make several flybys of the smaller moon Deimos before sending the Sample Return Capsule back to Earth, arriving in July 2029. The mission architecture uses three modules: propulsion module (1,800 kg), exploration module (150 kg) and the return module (1,050 kg). With the mass of Deimos and Phobos being too small to capture a satellite, it is not possible to orbit the Martian moons in