text:  NASA has canceled the Moon rover mission because of cost overruns and launch delays. The Viper rover was supposed to have launched late last year, but extra testing and rising costs kept that from happening. The rover's mission was to explore the moon's south pole to try to find water. NASA says it's already spent around $450 million on this project so far. The announcement comes days before the 55th anniversary of the Apollo 11 mission, which launched Neil Armstrong and Buzz Aldrin to the moon.