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mission – n. a flight by an aircraft or spacecraft to perform a specific task
spacecraft – n. a vehicle that is used for travel in outer space
dwarf planet – n. a body that looks like a small planet but lacks certain requirements allowing it to be called a planet
asteroid – n. any one of thousands of small planets that orbit the sun
comet – n. an icy object in outer space that can develop a long, bright tail made of dust when it passes near the sun
