By Linda Herridge,
NASA's Kennedy Space Center
For the first time since NASA's Apollo-era rockets and space shuttles lifted off on missions from Launch Complex 39 at Kennedy Space Center in Florida, one of the launch pads is undergoing extensive upgrades to support the agency's 21st century space launch complex.
At launch pad B, construction workers are removing the legacy flame deflector that sits below and between the left and right pad surface crawlerway track panels, along with Apollo-era bricks from both walls of the flame trench. A contract to perform the work was awarded earlier this year to Vanguard Contractors in Paducah, Ky.
"A new universal flame deflector is being designed that will support NASA's Space Launch System (SLS) rocket and a variety of other commercial launch vehicles," said Jose Perez Morales, the Pad Element project manager in the Ground Systems Development and Operations Program. "The bricks will be removed due to their age and because they are debonding from the flame trench structure."
Constructed specifically for space shuttle launches, the current flame deflector was designed to deflect the rocket exhaust away from the launch vehicle and launch pad to reduce the potential for damage. The flame trench bricks, which date back to the Apollo program, were installed during construction of the pad in the 1960s.
Perez Morales said the bricks have lost some of the bonding from the pad structure and represent a safety hazard for new launch vehicles and need to be replaced.
Dr. Bruce Vu, the Gas and Fluid Systems lead in the Design and Analysis Branch in Kennedy's Engineering Directorate, with assistance from NASA's Ames Research Center, at Moffett Field, Calif., worked with three different design concepts and used several computational methods to analyze each design's performance.
"We spent almost a year working with other NASA centers and the commercial space partners to come up with several concepts," Vu said. "The three primary objectives we focused on while evaluating these concepts were plume containment, surface pressure and thermal performance."
For several weeks, Vu and his team ran simulations of a single launch vehicle over a flame deflector concept, using Ames' supercomputer. They were looking for a deflector design that could withstand the high heat from plume exhaust, that did not result in plume blow-back, and whose surface pressure was within design margin limits.
"At the end of the simulations, we selected the best design and received approvals from the Engineering Review Board and the Element Integrated Team to proceed with the design," Vu said. "The design actually is closer to that of Apollo rather than space shuttle."
Now that the shape of the deflector has been selected, Vu said there are many other details to be worked out, including what kind of surface refractory to use and what to do about the south slope of the deflector where there will be no exhaust plume.
The universal flame deflector design must be able to accommodate the SLS and other commercial launch vehicles.
The firm Reynolds, Smith and Hills, with offices in Merritt Island, is designing the new flame deflector and the refurbishment of the flame trench. The design review currently is at the 30 percent phase.
"The goal is to create a deflector design that will be less costly to construct and more efficient," Vu said.
The new flame deflector and flame trench designs are schedule to be completed in early 2014. The construction of the flame trench and deflector is scheduled to start in early 2015.