Thursday, February 10, 2011

SDO Moved to the Launch Pad and the Winds Blew!

On February 9, 2010 the launch vehicle carrying SDO moved from the Vertical Integration Facility (VIF) to the launch pad at SLC 41. It was quite an impressive display. The upper picture shows the view from the VIF. Two locomotives pushed the launch stack at a comfortable walking speed toward the pad in the distance. Trailers filled with SDO computers that would monitor the spacecraft until launch are in front of the rocket and will be pushed into tunnels for protection during launch.

The next photo shows the stack as it arrives at the pad. (The towers are lightning arrestors that surround the pad.) The grey spar next to the rocket is an important player in the launch sequence. It supports power and telemetry cables to the payload and the Centaur second stage (the narrow part of the stack.) It also carries a tube that blows clean nitrogen into the instruments to keep away contaminants. On February 10 it played a different role. That morning the launch window opened at 10:26 am ET. The winds must be below a maximum speed to allow a launch to proceed. One direction, from roughly the northwest, is the most critical because such a wind would push the spacecraft toward the spar. Of course, the strong weather pattern that was pounding the Snowmageddon Launch Team in Maryland produced such winds. After waiting 50 minutes at T-10 minutes, the spacecraft was ordered into the final 10 minutes of the countdown. Two seconds after that the spacecraft detected wind gusts that were too high and shut down.

SDO would remain on Earth for another day.