|External Tank 94 inside the Vehicle Assembly Building at the Michoud Assembly Facility in Louisiana. Credit: NASA/MAF/Steven Seipel|
LOS ANGELES, California - The last surviving usable external tank built for the Space Shuttle program is on its way to Los Angeles, California.
On April 12, the external tank, dubbed ET-94, left NASA’s Michoud Assembly Facility in Louisiana on a weeks-long voyage to its new home at the California Science Center. ET-94 will travel by barge through the Panama Canal to Los Angeles and will ultimately be part of Endeavour’s one-of-a-kind vertical display in the future Samuel Oschin Air and Space Center. ET-94 is expected to arrive at the Science Center around May 21, 2016.
Three types of External Tanks (or ET’s) were manufactured for the Space Shuttle program: Original ET’s used during the first six missions were standard weight tanks (SWTs); improved tanks used throughout the 1990’s were lightweight tanks (LWTs); and super lightweight tanks or SWLTs. All three models were designed prior to the Space Shuttle Columbia accident, and all had the same appearance on the outside. ET-94 is a LWT and differs in internal construction and materials from the other two types.
ET-94 was one of three LWT tanks NASA ordered specifically to support science missions for the Space Shuttle Columbia. NASA and California Science Center officials thought it was a fitting day to begin ET-94’s historic journey because April 12 is a very special day in the history of spaceflight and Columbia. On April 12, 1981, the very first Space Shuttle, Columbia, lifted off from Kennedy Space Center in Florida.
Referred to as a “deferred-build” tank since production of SLWT’s had already begun, ET-94 was delivered to NASA in January 2001 but stored at the Michoud Assembly Facility because the first of the “deferred-build” tanks, ET-93, was involved in the Space Shuttle Columbia accident.
The Columbia Accident Investigation Board (CAIB) and NASA were interested in finding out if there was anything unique to the deferred-build tanks that contributed to the accident. The investigation's thorough examination of ET-94 explains why there are significant pieces of foam missing and cosmetic restoration will be necessary before it is assembled with the Orbiter museum display.