CAPE CANAVERAL, Fla. (AP) -- The ability to explore planets beyond our solar system will require space vehicles with nuclear-powered propulsion systems, NASA Administrator Sean O'Keefe said Tuesday.

After launching into space almost 50 years ago, NASA’s Voyager probes are reaching the end of their lives. The nuclear batteries onboard the two spacecraft are running out of juice, which means ...

NASA used its Mars Odyssey orbiter to capture a unique view of the largest volcano in our solar system, the colossal Martian feature Olympus Mons.