When guests visit the new Space Shuttle AtlantisSM attraction, they will be treated to a sight previously seen only by astronauts in space – Atlantis tilted at a 43.21-degree angle with its payload bay doors open as if it has just undocked from the International Space Station (ISS). What guests may not realize is how rare it is for the payload bay doors to be open when Atlantis is not in space.
Measuring 60 feet long, the 2,500-pound doors were designed to be opened in zero gravity, with a few exceptions, using a motorized mechanism that cannot function properly when the doors are under the full force of gravity on Earth. Not only that, the graphite epoxy composite doors are relatively delicate, making the proposition of displaying Atlantis with open doors a relatively tricky one. If not properly handled, the doors might have bowed, buckled or broken off their hinges.
To preserve the integrity of Atlantis, Kennedy Space Center Visitor Complex consulted with United Space Alliance (USA), the contractor that managed space shuttle processing for NASA. Many months were spent planning the step-by-step process to ensure there would be no damage to the priceless spacecraft.
Plans for opening the payload bay doors under the force of gravity already existed for three scenarios: in the Orbiter Processing Facility (OPF) at Kennedy Space Center; in Palmdale, Calif., where the orbiters were manufactured, and at the transoceanic abort landing (TAL) sites. None of the scenarios involved opening Atlantis’ payload bay doors while the orbiter was at such an extreme angle – 43.21 degrees. The team considered the processes from each site before developing a plan specifically for the Space Shuttle Atlantis attraction.
After much consideration, supporting the payload bay doors by stainless steel cables attached to the ceiling was considered the optimum method. Propping open the doors from underneath would have meant adding a bracing structure to Atlantis’ frame, which would have impeded guests’ views and not presented as authentic an experience.
The following briefly describes the process by which the payload bay doors are now supported by 12 quarter-inch stainless steel cables, six on each door.
- Four custom brackets, approximately 30 inches long, were installed inside each of the payload bay doors to help strengthen the doors in the open position and attach the cables. The remaining two cables connect to the forward and aft locking mechanisms inside the doors.
- Two strongbacks, normally used to stiffen and support the doors during ground opening were installed on each door to aid in the process.
- A spreader beam – from which the two strongbacks and their associated c-links were connected – was attached to a hoist in the ceiling of the attraction. This mechanism was used to support and open the doors.
- The starboard door was opened first to 160 degrees to allow the KU antenna (communications satellite dish) to be deployed. The door was then adjusted to a display position of 140 degrees.
- The port door is also open to 140 degrees to enable guests to see into the payload bay.
- In space, the payload bay doors remained open throughout the mission to diffuse excess heat from the aluminum radiators which are attached to the inside of the doors. They remained open until one hour before the de-orbit burn.
- Following the successful attachment of the cables, the four strongbacks were removed from the outside of the payload bay doors.
Despite the lengthy planning process and complexity of the task, opening Atlantis’ payload bay doors enables guests to fully appreciate the massive payloads – including the Hubble Space Telescope and modules of the International Space Station – the space shuttle was able to ferry into space.