Set to land on Mars August 5, NASA mission will search for signs that the planet could support life, now or long ago.

Ryan Anderson’s graduate work helped researchers select Curiosity’s landing site in Gale Crater.

NASA’s new Mars rover aims to alight on the Red Planet like a pop star being lowered onto stage.

Astronomy writer Nadia Drake looks back on the astronaut’s reach.

Researchers comb the Internet for snapshots of a comet and use the collected images to calculate its orbit. (p. 14)

Space telescope’s discovery announced on Twitter. (p. 8)

It was August 7, 1912, and Victor Hess was about to solve a mystery. The Austrian physicist climbed aboard a highly combustible, hydrogen-filled balloon, carrying three electroscopes — small, brass-enclosed instruments with metal-coated wires that separate when hit by charged particles. At the time, such invisible ions in the atmosphere were already an aging conundrum, having first been detected in 1785. His balloon lifted off from the Bohemian town of Aussig. It was just after 6 a.m. Six hours later, having soared to a chilly 5,300 meters, the balloon touched down near Berlin. Along the ... (p. 16)