ATK Aerospace Systems successfully test fires a five-segment solid-fuel booster near Promontory, Utah, as part of the Constellation moon program the Obama administration wants to cancel. Read More...

A $2 billion physics experiment bound for the International Space Station was delivered to the Kennedy Space Center Thursday after a busy summer of work to replace the magnet at the heart of the powerful particle detector. Read More...

NASA's Kepler spacecraft has found its first confirmed multi-planet solar system, including two Saturn-class worlds and a possible low-mass planet just slightly larger than Earth. The announcement follows a European discovery, using a different technique, of a solar system with up to seven planets. Read More...

Astronomers discover a solar system 127 light years away with up to seven planets, including one world just a bit larger than Earth. If confirmed, this would be the least massive extra-solar planet yet found. Read More...

NASA's $2.4 billion Mars Science Laboratory rover -- Curiosity -- is the most sophisticated unmanned lander ever built, a robot scientists hope will revolutionize humanity's understanding of the red planet (CNET repost). Read More...

In a high-speed computer-orchestrated descent jokingly referred to as "six minutes of terror," NASA's newest Mars rover will rely on a rocket-powered "sky crane" to lower the car-size robot to the surface (CNET repost). Read More...

Loaded with sophisticated instruments and a nuclear power pack immune to sunlight-dimming dust, NASA's Curiosity rover will search for carbon compounds and geologic clues about the habitability of the red planet (CNET repost). Read More...

If NASA wins political approval for one additional space shuttle mission, the agency is protectively considering a June 28, 2011, target launch date. Read More...

The International Space Station's coolant system is back up and running normally after a three-spacewalk repair job. The lab's U.S. astronauts discussed the repair work in an interview with CBS News. Read More...

A new study shows that astronauts on long-duration spaceflights experience significant muscle wasting and a surprising loss of force, suggesting new exercise techniques are needed to keep crews fit. Read More...

Astronauts Douglas Wheelock and Tracy Caldwell Dyson wrap up a seven-hour 20-minute spacewalk to install a replacement coolant pump aboard the International Space Station. Read More...

Realtime coverage of U.S. EVA-17 (loop A ammonia pump R & R part 3) Read More...

Astronauts Douglas Wheelock and Tracy Caldwell Dyson prepare for a third spacewalk Monday to install a replacement ammonia pump in a bid to complete coolant system repairs. Read More...

A United Launch Alliance Atlas 5 rocket boosted the first Advanced Extremely High Frequency military comsat into orbit Saturday. Read More...

NASA delays third coolant repair spacewalk to Monday; officials say fourth spacewalk likely to tie up loose ends and move faulty ammonia pump to more secure stowage location. Read More...

Realtime coverage of U.S. EVA-16 (loop A ammonia pump R & R part 2) Read More...

NASA managers have approved plans for a second spacewalk Wednesday to isolate a leaking ammonia line, allowing astronauts to remove a faulty pump module crippling the lab's coolant system. A third spacewalk will be needed Sunday to complete the repair. Read More...

NASA planners are revising plans for a second ISS coolant system repair spacewalk Wednesday to deal with an unexpected ammonia leak. A third spacewalk is expected Sunday, pending management approval, to finish the job. Read More...

An unexpected ammonia leak and a jammed quick-disconnect fitting derailed plans to swap out a faulty pump module aboard the International Space Station during a spacewalk Saturday. Read More...

Realtime coverage of U.S. EVA-15 (loop A ammonia pump R & R part 1) Read More...

Astronauts Douglas Wheelock and Tracy Caldwell Dyson make final preparations for a spacewalk Saturday to replace a coolant pump on the International Space Station. Read More...

Engineers are looking into how a metal washer made it into an external tank liquid oxygen feedline. Read More...

NASA managers decided Thursday to delay two upcoming space station coolant system repair spacewalks to improve planning and procedures. The EVAs now are targeted for Saturday and Wednesday. Read More...

Here is a preliminary timeline for a planned spacewalk Friday to replace a failed ammonia pump module in the International Space Station's cooling system. Read More...

NASA astronauts and engineers are refining plans for two spacewalks to replace a large ammonia pump module that shut down Saturday, knocking out one of the lab's two cooling loops. Read More...