4 words in this vocabulary list
noun a celestial object consisting of a nucleus of ice and dust and, when near the sun, a 'tail' of gas and dust particles pointing away from the sun
noun a celestial body that is smaller than a planet but larger than an asteroid
adjective describing something related to or resembling a planetoid
noun A maneuver in which a spacecraft uses the resistance of a planet's atmosphere to slow down or adjust its trajectory
noun the branch of science that deals with the upper atmosphere, especially with reference to its weather and climate