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.
Q: Category: ARE THE STARS OUT TONIGHT?
Clue: NASA says the next best windows for man to visit this planet & keep the trip short occur in 2003, 2018 & 2020
A:
mars