Home to NASA’s mission control, Houston, Texas, is proud of its historical prominence in space exploration. Space Center Houston, the Official Visitor Center, is one of the city’s top attractions and welcomes nearly one million eager visitors each year. When NASA’s shuttle program officially ended in July 2011, the remaining spacecraft were retired to museums around the country, but not one landed in Houston. Though disappointed with the decision, five years later the city would instead create a landmark that offers visitors an experience like no other.
KCI worked with the Manned Space Flight Education Foundation Inc., the non-profit owners of Space Center Houston, to help launch its newest exhibit, the one-of-a-kind Independence Plaza, which features a replica space shuttle mounted on top of the original NASA 905 shuttle carrier aircraft, a modified Boeing 747. Opened to the public on January 23, 2016, Independence Plaza is the first and only exhibit that allows visitors to explore the insides of both a true-to-life orbiter and one of only two of NASA’s shuttle carrier aircraft.
KCI was tasked with designing the heating, ventilation and air conditioning (HVAC) system for the exhibit. “You don’t want visitors to notice or even think about the HVAC system,” said Vice President Stephen M. Redding, PE, LEED AP. “It was our mission to keep temperatures consistent to make sure that guests were as comfortable as possible.” Engineers used expected occupancy rates to calculate the size of a common chiller and air handler that were placed atop the eight-story visitor access tower. Coordination was required with structural engineers to add roof supports to the building, which was already under construction, to ensure it could accommodate the additional 10,900 pounds of equipment.
The next challenge was routing the piping and ducts from the roof into and through the vehicles. While the shuttle, which had been built as a museum display in Florida, already had ductwork in place, the 747 required a completely new system. “Not being a traditional building, the plane required a lot of extra thought and planning,” said Paul Spana, Space Center Houston exhibits manager. “Engineers and technicians had to learn a lot about how the aircraft was constructed in order to design an HVAC system to fit inside without being too obtrusive.” Using a 3-D model of the plane, mechanical engineer Andrew S. Christensen studied each section of the aircraft to determine placement of the ductwork within the changing curvature of the aircraft body. The design team also had to avoid the functional components of the plane, including the jet fuel tank located just below the main passenger deck.
Although restricted space to route the mechanical systems required a high degree of detail and accuracy, we were able to meet the project time line with a design that was both unique and constructible.
Andrew S. Christensen, Engineering-in-Training
Keeping in mind the center’s goal of delivering an authentic spacecraft experience for visitors to Indepedence Plaza, the design had to consider aesthetics as well as functionality both inside and out. With no hollow walls or false ceilings, restricted access areas within the cabin were identified as spaces where ducts could be placed but remain unseen. “The vast interior of the fuselage was being transformed into a museum gallery,” said Spana. “At the same time it was very important to maintain the integrity of the interior so that visitors would still be able to see what the plane looked like before it was retired from service.” Exposed ductwork was permitted only in those areas where visitors could explore the shell of the aircraft. According to Christensen, the design team even incorporated diffusers that look like gaspers (shown right)—the overhead knob used by passengers to control airflow on commercial flights—to create a more authentic experience.
Piping from the tower to the aircraft also needed to be out of sight as much as possible. Engineers routed chilled water pipes through the side of the plane and pulled outside air through one of the 747’s existing air intakes, which are used to draw cold air from outside for distribution throughout the cabin in-flight. “A lot of teamwork and care went into determining how to hide as much of the equipment and ducting as possible,” said Spana.
A year after KCI was contracted to complete the HVAC design, the exhibit was ready to open to the public. A host of NASA officials, astronauts, and the mayor of Houston joined the community at a grand opening ceremony, where fireworks filled the skies above a banner exclaiming, “Mission Accomplished.” The completion of the nearly $15 million Independence Plaza brought a piece of Houston’s history back to the city, and turned the citizen’s disappointment of not receiving an authentic shuttle into a sense of pride in offering a one-of-a-kind learning experience.