Due to the weekend loss of the space shuttle Columbia, astronaut Peggy Whitson has cancelled her planned appearances at schools this week near her southern Iowa home. Dr. Whitson returned in December from a six-month mission aboard the International Space Station. NASA cancelled all public appearances by current astronauts. Joe Drake is superintendent of the Bedford School District and talked to Whitson on the phone Saturday afternoon.Drake says Whitson promised to visit the schools but it’s unclear when that’ll happen. Drake says classes -are- on a regular schedule today, despite the disaster Saturday that claimed the lives of seven astronauts, including Ames native Laurel Clark. Drake says he expects there’ll be discussion about the Columbia disaster in the various classrooms today.He says they’ll leave that up to the individual teachers, but he believes they’ll talk about the issue.Whitson had been slated to speak at schools in Bedford, Mount Ayr and Lamoni and at Graceland University in Lamoni.