What is this article mainly about?
John Callas is quoted saying, "We have now exceeded the prime–mission duration by a factor of 50…."
What does "exceeded" mean in his context?
What does "a factor of 50" mean to John Callas?
When was the Opportunity Rover expected to stop working?
What date was this article published?
What does "extended" mean in this context?
In the same quote (copied below), what does "series" mean?
"These activities are part of a two–year extended mission that began Oct. 1, the newest in a series of extensions going back to the end of Opportunity's prime mission in April 2004."
In the same quote (below), what is an "observation"?
"…Opportunity explored the 'Marathon Valley' area of Endeavour's western rim, documenting the geological context of water–related minerals that had been mapped there from orbital observations."
When does the article say that NASA is on track to send humans to Mars?
What forms part of the southern wall of Marathon Valley?
What else would you like to learn about the Opportunity Rover?