Detailed Instructions: You will be given a trivia clue, and the category it belongs to. You should answer with the best answer that belongs in the category and is described by the clue. For simplicity, answers should be in all lower cased letters.
Problem:Category: SPACE EXPLORATION 
Clue: Now 6 billion miles from Earth, Pioneer 10 originally was launched in 1972 on a mission to this planet
Solution:
jupiter