Double planet the four, small, outer satellites of Pluto. A now-abandoned hypothesis for the origin of the Moon was actually called the "double-planet hypothesis"; the idea was that the Earth and the Moon formed in the same region of the solar system's proto-planetary disk, forming a system under gravitational interaction. This idea, too, is a problematic condition for defining two bodies as "double planets" because planets can "capture" moons through gravitational interaction. For example, the moons of Mars (Phobos and Deimos) are thought to be asteroids captured long ago by Mars. Such a weak definition would also deem Neptune-Triton a double planet,
Mars Terahertz Microsatellite Wave Instrument) on board the Jupiter Icy Moons Explorer, which the institute jointly developed with ESA and DLR (German Aerospace Center). Unlike the Japanese Space Agency (JAXA), which is under the jurisdiction of the Ministry of Education, Culture, Sports, Science and Technology, NICT's parent agency is the Ministry of Internal Affairs and Communications (MIC). MIC formally approved the Mars Terahertz Microsatellite in early 2017. The preliminary lander's dimensions are a 50 cm cube, and may have a mass of including propellant. Its landing system is proposed to employ an inflatable aeroshell decelerator, and an airbag. Mars Terahertz Microsatellite The Mars