External Tank Assembly Flow

The following is an outline of the construction process for the Shuttle's huge orange External Tank (ET).

Intertank

• Intertank frame assembly
• Intertank panel installation
• Intertank structural & mechanical installations
• Bldg 420 TPS wedge bonding
• Cell D SLA spray

Oxygen Tank

• LO2 Barrel trim & weld
• Forward OGive trim & weld
• Aft OGive trim & weld
• LO2 tank assembly trim & weld (w/ dome)
• LO2 tank proof test
• Cell E internal clean & iridite ext clean
• Cell B iridite welds SBL & OGive prime
• Cell E aft dome ext clean
• Cell C aft dome prime
• Cell B cure
• Bldg 420 SLA panel bonding & aft dome SOFI

O&I

• VAB aisle stack
• Cell B LO2 Intertank SOFI spray

Dome

• Dome gores trim & weld
• 1:4 dome panel to chord trim & weld
• dome body trim & weld
• dome cap fittings trim & weld
• dome body & cap trim & weld

Hydrogen Tank

• LH2 forward barrel trim & weld
• LH2 aft barrel trim
• Barrel frame installation
• T frame assembly
• LH2 tank assembly trim & weld (w/ dome)
• LH2 tank proof test
• Cell E internal clean & iridite ext clean
• Cell C iridite welds prime & cure
• Bldg 103 SLA panel bonding SOFI fwd dome
• Cell C fwd dome & barrel SOFI spray
• Cell D aft dome SOFI spray

Entire External Tank

• Cell A mate LO2 intertank & LH2
• Final assembly operations
• Test & checkout Building 420
• Load on barge