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Zipping through space at nearly a million miles per day, NASA's New Horizons probe is halfway to Pluto and just woke up for the first time in months to look around. An artist's concept of New Horizons. "Our spacecraft is way out in exotic territory, in the middle of nowhere," says Hal Weaver, New Horizons project scientist at Johns Hopkins University. "And we have a lot to do." It's the perfect opportunity to test New Horizon's instruments before the probe reaches Pluto in 2015. "We don't want to miss a single breathtaking moment during the Pluto encounter," he says. "So we're checking everything out now to make sure we're ship-shape and ready to go." The 9 weeks of testing commenced on May 25th. Mission controllers plan a thorough checkout and recalibration of all seven science instruments onboard. First up is LORRI, the Long-Range Reconnaissance Imager, one of the largest interplanetary telescopes ever flown. "On July 14, 2015, the date of closest approach, we'll be able to distinguish objects on Pluto as small as a football field," says Weaver. "That's about 300 times better resolution than anything we have now."

On 10 July, the European Space Agency's Rosetta spacecraft will fly within a few thousand kilometres of 21 Lutetia, a main belt asteroid that orbits the Sun between Mars and Jupiter. Lutetia is an unusual object. It is classified as an M-type asteroid, which are thought to be made mainly of nickel and iron. However, Lutetia's spectrum does not seem to show any evidence of metals. In fact, exactly what Lutetia is made of puzzles astronomers. That's partly why it was chosen for the fly by. So come July, astronomers should know the answer to this conundrum. But in the run up, they're indulging in a little fun. The game they've invented is to see how good a prediction they can make about what Rosetta will find. Today, Irina Belskaya at the Observatoire de Paris and a few friends take a stab. They make several detailed predictions about Lutetia based partly on observations dating back to the 1960s but mostly on data taken since 2004, when interest picked up after the asteroid was chosen as a flyby target. So what do they think Rosetta will find?

Justin is a dexterous humanoid robot that can make coffee. Now it's learning to fix satellites. Justin was developed at the Institute of Robotics and Mechatronics, part of the German Aerospace Center (DLR), in Wessling, Germany. The robot has different configurations, including one with wheels. The space version has a head, torso, and arms, but no wheels or legs, because it will be mounted on a spacecraft or satellite. The goal is to use Justin to repair or refuel satellites that need to be serviced. Its creators say that ideally the robot would work autonomously. To replace a module or refuel, for example, you'd just press a button and the robot would do the rest. But that's a long-term goal. For now, the researchers are relying on another approach: robotic telepresence. A human operator controls the robot from Earth, using a head-mounted display and a kind of arm exoskeleton. That way the operator can see what the robot sees and also feel the forces the robot is experiencing.

For some years now, an unorthodox idea has been gaining favor among astronomers. It contradicts old teachings and unsettles thoughtful observers, especially climatologists. "The sun," explains Lika Guhathakurta of NASA headquarters in Washington DC, "is a variable star." But it looks so constant... That's only a limitation of the human eye. Modern telescopes and spacecraft have penetrated the sun's blinding glare and found a maelstrom of unpredictable turmoil. Solar flares explode with the power of a billion atomic bombs. Clouds of magnetized gas (CMEs) big enough to swallow planets break away from the stellar surface. Holes in the sun's atmosphere spew million mile-per-hour gusts of solar wind.

This week, Mercury is emerging from the glare of the sun and making a beeline for Venus. By week's end, the two planets will be just 3o apart, an eye-catching pair in the deep-blue twilight of sunset. The best nights to look are April 3rd and 4th. Go outside at the end of the day and face west. Venus pops out of the twilight first, so bright it actually shines through thin clouds. Mercury follows, just below and to the right: April 3April 4 Venus is an old friend to most sky watchers; Mercury, less so. The first planet from the sun spends most of its time wrapped in painful sunlight. Seeing it so easily, and in the beautiful company of Venus no less, is a rare treat indeed. The next apparition this good won't come until Nov. 2011. By that time, however, we'll have much better view of Mercury all the time. NASA's MESSENGER probe is en route to Mercury now, and in March of 2011 it will become the first spacecraft to orbit the planet. During a year-long science mission, MESSENGER will beam back a stream of high-resolution pictures and data obtained using seven instruments designed to operate in the extreme environment near the Sun. This kind of coverage of planet #1 is unprecedented.