SATURDAY, JUNE 18 "Megalightning" at 8P et/pt The space shuttle Columbia had the task of recording giant lightning from space as part of its mission. Was megalightning a factor in the shuttle disaster? Watch a preview. http://ng.chtah.com/a/tBCra2KASJ4TXAXLFyxAOOv6R.ASJ-ROen/ngs2