Solar System all have impact craters and tectonic surface features, such as rift valleys and volcanoes. The term "inner planet" should not be confused with "inferior planet", which designates those planets that are closer to the Sun than Earth is (i.e. Mercury and Venus). Asteroids except for the largest, Ceres, are classified as small Solar System bodies and are composed mainly of refractory rocky and metallic minerals, with some ice. They range from a few metres to hundreds of kilometres in size. Asteroids smaller than one meter are usually called meteoroids and micrometeoroids (grain-sized), depending on different, somewhat arbitrary definitions. The asteroid
Outer Planet Flagship Mission Outer Planet Flagship Mission The Outer Planet Flagship Mission is a type of NASA program to research larger size missions to the outer solar system, and some examples of this type of mission are Galileo or Cassini-Huygens. In 2013 after encounter some technical issues and funding in the early 2010s, development was paused although overall research continued. One issue is the other big NASA missions such as in astrophysics and another is availability of RTG's One proposal was a joint mission between NASA and ESA to send a probe to study the icy satellites of the outer Solar System. There