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“Columbia” Prepares for the Future Space Shuttle Orbiter 102 undergoes major modification at Boeing’s Palmdale plant by Michelle Evans
The Space Shuttle fleet is nearly 20 years old and the technology on which the systems were built date back even further. The original intent of the shuttle was to be a cargo truck that carried crew and supplies to and from the Space Station. We are only now closing in on this goal. In the meantime the shuttle has served as satellite and planetary probe launch pad, micro-gravity experiment facility, as well as putting some of the components of the International Space Station into orbit so that the shuttle finally has a place to go to fulfill its original mission.
Current estimates show that the shuttle orbiters will be used for another 20 to 30 years. To achieve this longevity, major modifications have been ordered which will bring the fleet up to more modern standards.
The most notable of these changes includes a new system called MEDS. This is the Multi-function Electronic Display System. It is also known in simpler terms as the “glass cockpit” (see O.C.SPACE, Nov. 98). The MEDS system will replace three original-equipment cathode ray tubes and a good portion of the dials and meters that used to show the crew the status of the shuttle. MEDS instead uses nine flat-screen, full-color liquid-crystal displays to do this job. Not only will this make the orbiter safer to fly, it will make it much faster, cheaper, and easier to maintain.
Accomplishing these changes means that each orbiter will be sent back to the original construction plant at Palmdale, in the California desert, for extended periods of what is known as a “major mod.” Atlantis has already undergone the MEDS upgrade and first flew into orbit in April. Columbia is the second or the four orbiters to return to Palmdale.
Since Columbia was the first shuttle orbiter to enter space (April 12, 1981), it was instrumented heavily for the original flight tests. Now, with 26 spaceflights of this vehicle completed, it is felt that much of the wiring for the instrumentation can be removed and Columbia will become a much closer companion ship to the rest of the fleet. In addition, this wire removal will save 1800 pounds of weight which directly translates into larger payloads carried into space.
The last flight of Columbia (STS–93 in July 1999) also has shown that problems have crept into the orbiters over the years as wiring became damaged inadvertently during maintenance. At launch, Columbia nearly lost engine power because of faulty wiring, which would have been disastrous that close to the ground with no way to abort.
Now that Columbia has returned to Palmdale, extra care is being spent to go through literally every wire and connection to look for any possible damage. When the MEDS modifications, wiring inspections, tile repairs, and all the rest are completed later this year, Columbia will be returned to the Kennedy Space Center in Florida and returned to service.
About six months into the year-long modification process, it is hard to believe that Columbia ever flew in space. Hidden under layers of scaffolding it looks more like a giant jigsaw puzzle with many pieces still in the box. Some of these pieces have been removed completely to support operational orbiters at KSC. One such device is the power drive unit in the tail that controls the shuttle’s rudder and speed brake which was installed on Atlantis due to a lack of spare parts.
Everywhere you look, there are green tags hanging from heat protection tiles, electronic components, and mechanical assemblies. These tags are “Squawk Location Tags,” or places where work has yet to be completed.
Temporary clean rooms are set up at many locations such as the engine compartment at the rear of the orbiter and around the doors on the belly of Columbia where fuel connections are made with the External Tank. These are created by sealing the area with transparent green plastic and duct tape. Anyone that goes inside a clean area must wear a “bunny suit.”
The most notable clean room environment is the flight deck of the orbiter itself. |
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