spacetoday.net: Endeavour countdown begins

Posted: Wed, May 29, 2002, 8:13 AM ET (1213 GMT)
STS-111 patch (NASA)

The countdown towards Thursday's launch of the shuttle Endeavour started early Tuesday with weather posing the greatest chance of delaying the mission. The exact time the countdown started was not released, given NASA's post-September 11 policy of not disclosing exact launch times, but would likely have started late Monday night in order to support a launch of mission STS-111 between 4 and 8 pm EDT (2000 and 0000 GMT) Thursday. An exact launch time will be released late Wednesday. Weather is the major concern for Thursday's launch attempt: forecasts call for a 60 percent chance of unacceptable weather on Thursday, increasing to 70 percent on Friday and Saturday, because of late-day thundershowers. There are no technical concerns, after workers successfully repaired a leaking valve in a cooling unit in the orbiter over the weekend. STS-111 is a crew transfer mission for the station, as Endeavour brings the Expedition Five crew of Valeri Korzun, Peggy Whitson, and Sergei Treschev to the station and returns to Earth the Expedition Four crew of Yuri Onufrienko, Daniel Bursch, and Carl Walz, who have been in space nearly six months.