Lightning struck a water tower about 500 feet from the shuttle on Thursday at Cape Canaveral and despite a 30 percent chance of acceptable weather, the launch is still planned for 11:26 EDT.
Roads were clogged around Merritt Island, FL leading to the launch site. About three quarters of a million people were expected to come watch the launch in person.
VIP members at the Kennedy Space Center to watch the last shuttle launch include 14 members of Congress, Attorney General Eric Holder, singers Jimmy Buffett and Gloria Estefan, and Apple co-founder Steve Wozniak.
NASA expects private companies like Space X to make trips to the International Space Station and fill the gap left by the end of the shuttle mission, and Space X is planning a test flight to the ISS later this year.