Look up. Somewhere out there — beyond the high-rises and the clouds and yes, even the airplanes — there are people. To be precise, there are two of them, and they are more than three-and-a-half hours into the first spacewalk of the year. Astronauts Scott Tingle and Mark Vande Hei are expected to spend more than six hours Tuesday dangling off the side of the International Space Station, where they are installing a new gripper on the station's robotic arm.