page_title: Timeline of STS-121
section_title: July 3 (No launch attempt)
hierarchical_section_title: Timeline of STS-121 / July 3 (No launch attempt)
caption_attribution_description: A piece of insulation foam came off a bracket which held an oxygen line in place on the external tank ET-119 for STS-121. The left image shows the position of the bracket on the external tank, the middle image shows the crack in the insulation and the right image shows the piece of insulation that came off.
context_page_description: This is the timeline for STS-121, the mission to the ISS.
context_section_description: The shuttle's fuel cells were replenished to improve the chances of having enough electrical power on orbit to enable the third planned space walk to take place.
  Cracks and a region where a piece of foam had come off were discovered in the insulation on the upper part of the external fuel tanks. The foam came off a bracket which held an oxygen line in place. The fragment that fell off weighed 0.0056 pounds (2.6 grams) and, according to NASA, would not be big enough to damage the shuttle if it were to come off during flight. The thermal stresses of repeated filling and emptying the fuel tank with the cryogenic fuel are known to cause a degree of damage to the insulation foam.
caption: Images, from left to right showing 1. The external fuel tank area showing the location of the liquid oxygen feedline bracket. 2. Detail of the bracket showing cracked and missing foam. 3. Fragment of foam that fell off.  Photo credit: NASA
exif: {}