NASA's biggest rocket yet aims for 2017 test flight

NASA's largest rocket yet, a vehicle under development called the Space Launch System (SLS), is on track for its first test flight in 2017, according to experts who spoke at the Space Tech Expo in Long Beach last month.The rocket is designed to carry astronauts farther into the solar system than ever before. Meanwhile, NASA plans to leave travel to low-Earth orbit to commercial space companies, wh...