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At some 36 million miles from the sun, temperatures on the planet's daylight half hit 800 degrees F., while temperatures on the night half plunge to nearly minus 300 degrees F. – a 1,100-degree temperature swing that the craft will experience every 12 hours. The craft is outfitted with a ceramic-cloth sun shield that sheds enough of the sun's heat to keep instruments inside the orbiter at room temperature. Solar panels, which ordinarily would aim face-on to the sun, must be feathered, like a rowboat oar, to keep the panels from overheating. In addition, the panels contain mirrors to help...

Mercury, the smallest planet, bakes in the heat of the Sun, but it has water in some form. It has volcanoes. It appears to have an active magnetic field generated by a molten iron core. And it has shrunk more than scientists thought. Those are some of the findings gleaned from the flyby of NASA’s Messenger spacecraft in January, the first close-up look since Mariner 10 flew by three times in the 1970s. “After five months of analysis, we’ve got some fascinating new results, and some of them have resolved debates that are more than 30 years old that go...

CAPE CANAVERAL, Fla. (AP) - NASA is about to embark on its hottest mission ever, to Mercury. The Messenger spacecraft, to be launched next week, will be blasted by up to 700-degree heat as it orbits the tiny planet closest to the sun - so close that it would be as though 11 suns were beating down on Earth. Remarkably, the only thing between the probe's room-temperature science instruments and the blistering sun and pizza-oven heat will be a handmade ceramic-cloth quilt just one-quarter of an inch thick. "If it doesn't stay toward the sun, it will fry everything," said...