End of an Era: Final Weather Blog Before Launch

By Carla Voorhees

Kathy Winters is an Air Force Civilian Meteorologist at the 45th Weather Squadron at Cape Canaveral Air Force Station. She is the Space Shuttle Launch Weather Officer providing weather support to the Space Shuttle Program at Kennedy Space Center (KSC) as the Launch Team prepares for the 8 July 2011 launch of Atlantis. You can find out more about the 45th Space Wing at their Facebook page.

Thursday, I was getting ready to write my last update before I left for the day when a close lightning stroke occurred at the Shuttle Launch Pad. When we first get the data that a close lightning strike occurred, we aren’t really sure exactly where it hit. We can, however, give a pretty close estimate, and we also provide data that shows an ellipse in which we can give a 99% confidence the strike occurred within the ellipse. We can also give the probability the strike occurred within 0.45 nautical miles (nm) of the vehicle. In this case, the probability the lightning was within 0.45NM of the vehicle was 100%, so we knew we had a close strike. The ellipse is almost a circle because all 5 of our lightning sensors detected the strike. The photo shows where our Cloud–to-Ground Lightning Surveillance System detected the strike and how intense it was. We provide maps of this data to the launch team so they can determine if the stroke impacted any systems. They use information from the lightning detection system at the launch pad as well as cameras around the launch pad to determine where the stroke actually hit.

So far the only impact this strike had on Shuttle operations is a delay in Rotating Service Structure (RSS) retract Thursday afternoon. The delay occurred due to the thunderstorm first, and then the need for the team to complete a walkdown and inspection of the area after a lightning strike. The team uses the RSS for access to complete this walkdown. The RSS is then retracted, but the team will still assess all the systems to ensure the lightning did not cause any induced current on the Shuttle systems.

I am heading home for crew rest, but we have personnel on shift to cover any more significant weather that occurs this before launch. I will not be able to blog during the countdown, but I will write again after launch while the Shuttle is on orbit. Wish us luck tomorrow!