Spacewalking astronauts spent their second day outside the space shuttle Columbia on Tuesday, adding a second new solar array to the Hubble Space Telescope. During the 7-hour, 16-minute spacewalk, astronauts James Newman and Michael Massimino also replaced one of the telescope’s stabilizing gyroscopes. The newly installed solar arrays are smaller than the telescope’s previous arrays, but they actually provide 20% more power. Three more spacewalks are still planned.