What would you like to know about living and working in space? On Friday, astronaut Donald Pettit
and former astronaut Jeffrey Hoffman
will be on the program to answer questions from our listeners as we open the phones for another in our "Ask an Expert
Call in during the show on Friday or leave your question in the comments below. In the meantime, to prepare for Friday's conversation, you can listen to some of Pettit and Hoffman's prior visits with Science Friday, and check out a couple of physics demonstrations Pettit filmed while aboard the International Space Station for his "Science off the Sphere
" video series.