Deimos and Phobos Interior Explorer Deimos and Phobos Interior Explorer Deimos and Phobos Interior Explorer (DePhine) is a European mission concept to use a dedicated orbiter to explore the two Moons of Mars: Phobos and Deimos. The mission concept was proposed in 2016 to the European Space Agency's Cosmic Vision programme for launch in 2030, but it was not chosen as a finalist for the M5 mission class. DePhine was proposed in 2016 to ESA's Cosmic Vision programme as an M-class (medium class) mission for launch in 2030 as the M5 mission. It was proposed by the Institute of Planetary Research of the German Aerospace
Definition of planet object can be irregular in shape, but beyond that point gravity begins to pull an object towards its own centre of mass until the object collapses into an ellipsoid. (None of the large objects of the Solar System are truly spherical. Many are spheroids, and several, such as the larger moons of Jupiter and Saturn and the dwarf planet , have been further distorted into ellipsoids by rapid rotation or tidal forces, but still in hydrostatic equilibrium.) However, there is no precise point at which an object can be said to have reached hydrostatic equilibrium. As Soter noted in his