NASA cancelled Saturday's launch attempt of space shuttle Endeavour on a construction mission to the International Space Station to assess possible damage from nearby lightning strikes.
The space agency reported 11 lightning strikes less than three-quarters of a kilometre from the launch pad.
The shuttle is protected from direct strikes by lightning masts and wires that divert currents to the ground, however the concern about nearby strikes is that related electromagnetic fields could trigger currents in the shuttle's electrical systems.
Launch was reset for 7:13pm local time on Sunday from Cape Canaveral in Florida.
The shuttle is carrying a porch for Japan's Kibo laboratory that will be used to expose experiments to the open environment of space.
The delay is the third in the past month for Endeavour. NASA tried twice last month to launch Endeavour, but was stymied by potentially dangerous hydrogen fuel leaks.
