UPDATE: New images have been added, showing the piece disassembled.
Impressive forward External Tank (ET) separation bolt assembly from Space Shuttle Atlantis flown on STS-110, measuring approximately 6.25″ in diameter and 10.25″ long, with a weight of 52 pounds, marked on the base: "Shear Bolt, SKD26100098-245, Mfg Date 02-98, SN-17610-00021-HCB." The forward ET shear bolt structurally ties together the Space Shuttle Orbiter and External Tank at the forward attach point; it has two threaded ports for pyrotechnic NASA Standard Initiator (NSI) pressure cartridges. When the cartridges are activated, the central piston fires and shears the attachment bolt, allowing the tank to be jettisoned. Accompanied by a NASA Unserviceable Parts Tag, stamp-dated May 31, 2002, with remarks: "Ship to JSC EP-5," and a photocopy of the NASA post-flight shipping document from KSC to JSC. Originates from the collection of a retired NASA Astronaut.
STS-110, an International Space Station assembly mission, marked the 25th flight of Space Shuttle Atlantis (OV-104). Launched on April 10, 2002, the astronauts conducted four spacewalks during the ten-day mission to install the S0 Truss segment (the backbone of the truss structure on the ISS), reconfigure Canadarm2 for the truss, and install future EVA hardware.
