You must have a valid passport to participate in a study or intern program outside the U.S. Your passport should be valid at least six months after the end of your program.
Getting a passport is easier than you think. Here's what you do:
NOTE: Request a passport "booklet," not a "card." You will not need both.
Mail Form DS-82 in a padded envelope to the address listed on the form, along with:
See instructions online: http://travel.state.gov/passport/renew/renew_833.html.