Close-up view of the liftoff of the Shuttle Challenger on mission STS-51L taken from camera site 39B-2/T3. From this camera position, a cloud of grey-brown smoke can be seen on the right side of the Solid Rocket Booster (SRB) on a line directly across from the letter "U" in United States. This was the first visible sign that an SRB joint breach may have occured.