Both halves of a frangible nut from the rear External Tank (ET) strut of Space Shuttle Atlantis flown on STS-110, measuring approximately 5″ x 5″ x 4″, marked with part numbers: "SKD26100099-302, 06-98, 21356-00024-HDB." Frangible nuts are designed to be explosively split apart in order to sever mechanical connections, and are most well-known for their use in the jettison of Solid Rocket Boosters (SRB). They were also used for separation of the two aft structural attachments of the External Tank prior to orbital insertion. The attach bolts were driven by the explosive force of NASA Standard Detonators (NSDs) and a spring into a cavity in the tank strut. The nuts and all residual pieces of the NSDs were caught in a cover assembly within the Shuttle. This flown frangible nut, used on STS-110, is visually intriguing due to the 'puzzle piece' nature of the corresponding jagged edges. Accompanied by a NASA Unserviceable Parts Tag, stamp-dated June 3, 2002, with remarks: "Route to attn: JSC EP-5, OV-104, Post Flight 25," 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.
