NASA's John F. Kennedy Space Center
Repairing the panels on the surface of Launch Pad 39B and the catacomb roof below them is not a simple task. The pad is being prepared to launch NASA's newest rocket, the Space Launch System (SLS), beginning in 2017.
The pathway to the top of the pad supported the weight of the crawler-transporter that carried the Apollo/Saturn stack, and the space shuttle with external fuel tank and twin solid rocket boosters atop the mobile launcher platform (MLP). Now this pathway is being upgraded to support SLS and a variety of other launch vehicles.
[image-62]"We have a number of construction projects going on in the same area, so coordination with various contractors will be the major challenge of the work," said Jose Perez Morales, the pad element senior project manager in the Ground Systems Development and Operations (GSDO) Program at Kennedy Space Center in Florida.
When each of the pads at Launch Complex 39 was constructed, the flame trench and deflector were built above the ground. The two main structures that divide the flame trench served as the platform to support the MLP and launch vehicle. The top of these structures is the roof of the catacombs on both sides of the flame trench.
The surface panels and catacomb roof are separated by two inches of sand and five inches of lightweight concrete. Over the years, water seeped through the panel joints and accumulated between the top of the catacomb roof and the bottom of the panels.
Perez Morales said the water seeped into the concrete and caused spalling and some rebar corrosion. During a design review last year, Kennedy's Center Operations Directorate removed panels to test the structural integrity of the roof and determine the extent of damage to the concrete.
The work began Jan. 28 as specialists with the contractor Speegle Construction used power hoses to remove caulking between the giant panels. When that work is completed, the panels will be surveyed to determine their exact position for future reinstallation before they are removed.
There are 176 panels, each weighing about 30,000 pounds. Using a forklift, each panel will be lifted and set aside. All of the sand will be removed, and the structural roof of the catacomb will be repaired.
A special mat and drain system will be added on top of the roof to remove the water that seeps below the panels. New sand and lightweight concrete will be installed. Then the refurbished panels will be transported back to the pad and reinstalled. Twelve new panels will be fabricated by the contractor to replace the ones that were damaged. The upgrades will take about a year to complete.
"The catacomb roof provides the structural capability to support the combined weight of the crawler, the mobile launcher and the vehicle as they are transported up the slope to the top of the pad," Perez Morales said. "This project will refurbish the structural roof to provide that capability for all future SLS and commercial launches."
SLS will first launch in 2017 on Exploration Mission-1. The flight test will send an uncrewed Orion vehicle around the moon.