KENNEDY SPACE CENTER, Florida (CNN) — A scheduled March 15 launch has been delayed after the external fuel tank attached to the shuttle Atlantis and possibly the orbiter itself were damaged by a hailstorm at the launch pad Monday afternoon.
NASA meteorologists say wind gusts of 62 miles per hour and golf-ball-size hail were observed at pad 39A, where Atlantis was undergoing final preparations for launch.
Workers at the Kennedy Space Center in Florida are still assessing the extent of the damage, but NASA managers decided Atlantis must be rolled back to the Vehicle Assembly Building for thorough inspections and repairs.
The rollback means Atlantis will not launch in March as planned. Program officials hope repairs can be completed for a launch in late April or May.
Read the rest (and see the video) here …
– Ward
Why exactly is it that the Space Shuttle fuel tank is coated in this foam ?
RTLM:
This from Justine Whitman over at aerospaceweb.org: “As the Space Shuttle rises through the atmosphere, the outer surface of the tank is heated by friction with the external air that rushes past the vehicle at very high speeds. A thermal insulation coating is needed on the outer surface to maintain a constant temperature inside. Without this insulation, the cryogenic fuels would become warmer and start to convert back into a gas, raising the pressure inside the tank and possibly causing it to disintegrate. The thermal insulation is a 1 inch (2.5 cm) thick polyisocyanurate foam sprayed on the outer surface of the tank.
“This insulation is also important for reducing the formation of ice on the outside of the tank while it is sitting on the pad prior to launch. Ice has always been one of the greatest concerns of NASA engineers since it would likely fall off the tank during launch and could impact the Orbiter. Large chunks of ice can be very heavy and dense, so any impacts against the heat tiles on the lower surface of the Orbiter could easily damage these critical surfaces.”
Is this layer of foam easily damaged? Like the thermo-tiles on the orbiter? I understand rocket-science is, well, rocket-science, but why is it the whole space shuttle system looks so extremely fragile? Or is it just the old ‘risk= chance*cost’ again?
The ET is covered in foam to keep the liquid oxygen and liquid hydrogen within the ET cold and insulated, like a big thermos bottle. The hydrogen fuel and lox must be under pressure to keep in a liquid state and it is very, very cold.If it isn’t properly insulated, it will warm up, turn to gas and have to be vented off, wasting fuel.
The foam is almost the same quality and consistency as surfboard foam. Light, porous and easily shaped with a planer.It is applied as a liquid and hardens to a brittle foam. Recall a piece the size of a briefcase punctured the RCC leading edge of the Columbia which caused the loss of that orbiter.