Posted: Mon, Aug 6, 2007, 8:41 PM ET (0041 GMT)

The countdown for Wednesday evening's launch of the space shuttle Endeavour remains on track with no significant problems reported. Countdown clocks for the STS-118 mission to the ISS started Sunday evening towards a launch Wednesday at 6:36 pm EDT (2236 GMT). No technical issues have been reported during the countdown, and forecasts call for a 70-=percent chance of acceptable weather at launch time. Endeavour is on a mission to deliver supplies and install a new truss segment on the ISS. The mission's crew includes Barbara Morgan, a former teacher turned astronaut who was Christa McAuliffe's backup in the Teacher in Space program in the 1980s.