Weather conditions over NASA's Kennedy Space Center (KSC) are expected to prohibit a launch with a 60% chance of today's ascent of Space Shuttle Discovery, planned for 21:35h local time, being scrubbed due to cloudy skies.
Clouds can contain electrical charge and represent a lightning danger to an ascending Shuttle. Under NASA launch rules clouds that could contain such a charge cannot be closer than 32km (20nm) to KSC. If the launch is cancelled NASA is unlikely to attempt Friday as that day has a 90% chance of weather prohibiting launch and Saturday is currently at 70% against.
If Friday and Saturday are abandoned as launch days NASA is likely to stand down launch preparations for a day before trying again. This is because KSC can hold three-days of the Shuttle's cryogenic propellant, liquid hydrogen and liquid oxygen, and then has to transport more to the space centre. There are also personnel issues regarding working patterns that impact on the launch attempt timetable. However Sunday is forecast to begin a trend of better weather.
"The best day over the next six days is Tuesday but we can't put a percentage on that," says US Air Force 45th weather squadron technical sargent Matthew Timmermann. Discovery's mission STS-116 is the 117th Shuttle mission, the 20th US mission to the International Space Station (ISS) and the Orbiter's 33rd flight.
During the mission's three extra-vehicular activities astronauts will install the P5 port truss segment, retract the P6 port solar array's wing and radiators and move power cables to enable the ISS to draw power from then arrays installed in September by Space Shuttle Atlantis' crew on STS-115.
Clouds can contain electrical charge and represent a lightning danger to an ascending Shuttle. Under NASA launch rules clouds that could contain such a charge cannot be closer than 32km (20nm) to KSC. If the launch is cancelled NASA is unlikely to attempt Friday as that day has a 90% chance of weather prohibiting launch and Saturday is currently at 70% against.
If Friday and Saturday are abandoned as launch days NASA is likely to stand down launch preparations for a day before trying again. This is because KSC can hold three-days of the Shuttle's cryogenic propellant, liquid hydrogen and liquid oxygen, and then has to transport more to the space centre. There are also personnel issues regarding working patterns that impact on the launch attempt timetable. However Sunday is forecast to begin a trend of better weather.
"The best day over the next six days is Tuesday but we can't put a percentage on that," says US Air Force 45th weather squadron technical sargent Matthew Timmermann. Discovery's mission STS-116 is the 117th Shuttle mission, the 20th US mission to the International Space Station (ISS) and the Orbiter's 33rd flight.
During the mission's three extra-vehicular activities astronauts will install the P5 port truss segment, retract the P6 port solar array's wing and radiators and move power cables to enable the ISS to draw power from then arrays installed in September by Space Shuttle Atlantis' crew on STS-115.
The STS-116 crew are NASA astronauts William Oefelein, pilot; Mark Polansky, commander; Joan Higginbotham, Robert Curbeam, British born Nicholas Patrick, Sunita Williams and the European Space Agency's Christer Fuglesang, all mission specialists. Curbeam, Fuglesang and Williams will conduct the space walks. Williams will join the ISS's Expedition 14 in progress to serve as a flight engineer aboard the station.
Source: FlightGlobal.com
