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Detail of the number 5 engine liquid hydrogen feed line (at center of the photo). Also note the number 2 engine feed line at the top of the photo.

The S-shaped duct at lower left is the engine compartment conditioning duct.

The engine compartment conditioning system provided 300 to 500 pounds per minute of gaseous nitrogen to the engine compartment to prevent hazardous gas accumulation, formation of liquified air (due to the extreme temperatures of the liquid hydrogen), and to maintain proper thrust structure temperature.