Six weeks after its engines fizzled with less than a second before takeoff, the space shuttle Endeavor soared into space early this morning on a 10-day mission to help scientists get a grip on environmental problems brought on by industry and agriculture. But the crew of six has a few other jobs in mind for Endeavor's new $366 million radar system, including scans of the Silk Road traveled by Marco Polo 700 years ago, the radiation-contaminated land around Chernobyl, and the habitats of endangered pandas.