How soon will LC-39A be at significant risk to storm-surge damage?
It is currently at risk to storm surge damage, and measures have been and will continue to be taken to mitigate risk.
This answer is about engineering of beaches and seawalls, but it's likely that waterproofing of the launch structures themselves has been attended to as well. Hopefully a separate answer will address that.
Launch Pad 39B at Kennedy Space Center has been the site of dozens of Apollo era and space shuttle launches. Future SLS and Orion spacecraft will lift off from this site. (NASA)
From earthobservatory.nasa.gov's Launching from a Sandbar
The high-tide line has been moving landward for some time at Kennedy Space Center on Florida’s east coast. Located within the Merritt Island National Wildlife Refuge and adjacent to Cape Canaveral Air Force Station, NASA’s most famous center covers more than 66 square miles (170 square kilometers) and holds about 20 percent of the agency’s constructed assets. Most of it is built on coastal marshland about 5 to 10 feet above sea level.
Conservative climate models project that the seas off Kennedy will rise 5 to 8 inches by the 2050s, and 9 to 15 inches by the 2080s. If ice sheets in Greenland and Antarctica continue to melt as quickly as current measurements indicate, those numbers could become 21 to 24 inches by the 2050s and 43 to 49 inches by the 2080s.
“We consider sea-level rise and climate change to be urgent,” said Nancy Bray, spaceport integration and services director for Kennedy.
In 2004, three hurricanes crossed the Florida peninsula. And while none made a direct hit on Cape Canaveral, they collectively caused $100 million in damage to the space center. Then a nor’easter in 2007 sat offshore for two weeks and battered the beach; Tropical Storm Fay then raked the beach again in 2008.
In response to the persistent storm damage, Kennedy facilities managers contracted to build a 15-foot-high, 725-foot-long dune as a proof of concept for a managed retreat. Center scientists and engineers also worked with the U.S. Geological Survey to map the shape of the beach (topography) with laser ranging and detection (LiDAR). Then they enlisted coastal geologists John Jaeger and Pete Adams of the University of Florida to figure out why sand dunes near launch Complexes 39A and B were so persistently being washed away.
From NASA Goddard Institute for Space Studies' and Center for Climate Systems Research, Earth Institute, Columbia University's Cynthia Rosenzweig's paper in the Bulletin of the American Meteorological Society Enhancing Climate Resilience at NASA Centers: A Collaboration between Science and Stewardship:
At the Kennedy Space Center, coastal storms have been an ever-present hazard since NASA purchased 200 square miles of land in 1961, north and west of the Air Force launch pads at Cape Canaveral. Now, a Dune Vulnerability Team is addressing potential sea level rise and future storm-surge impacts to coastal facilities and infrastructure at Kennedy Space Center, especially Launch Pads 39A and 39B, which have played a critical role in space flight programs (NASA 1978, 2010). The Dune Vulnerability Team is designing an engineering approach to managing coastal erosion and preparing an environmental assessment under the National Environmental Policy Act (NEPA). Options to provide long-term protection of the launch sites include construction of a three-mile secondary inland dune, and dune and beach nourishment (NASA 2012). Climate risks have also been factored into the master planning process for ongoing twenty-first century spaceport facilities modifications and upgrades and the Kennedy Space Center 2012–2031 Future Development Concept (available online at http://kscpartnerships.ksc.nasa.gov/documents/KSC_FDC_Brochure.pdf). Finally, the Kennedy Space Center Sustainability Program is incorporating climate risk information in the planning process for facilities designs to address energy efficiency (NASA 2012).
NASA’s Climate Adaptation Sciences Investigators Workgroup (CASI) shares this concern. In a recent review of the space agency’s climate vulnerability, this team of in-house Earth scientists and facilities managers cited extreme weather and flooding as major hazards to future operations at Kennedy. Even under modest sea level rise scenarios, ten-year flood events are expected to occur two to three times as often by mid-century. And the more the ocean rises, the easier it’ll be for storms to cause flooding.
“We’re drawing a line in the sand,” Dankert says.“The dune not only prevents storm surge from plowing inland, it’s a sand source that replenishes the beach.”
For the past few years, the dune has held strong, preventing the ocean from spilling over onto the historic shuttle railroad that traces along the coast. Eventually, NASA would like to put in another two miles of dune, fortifying the entire shoreline between Launch Complexes 39A and 39B.
As with all government projects, the hang-up is funding. The post-Sandy dune reconstruction was completed for a cool $3 million, using beach-quality sand trucked up from Cape Canaveral. “We got really lucky—that sand was a big cost-saver,” Hall says, noting that the bill might have run in the tens of millions had NASA been forced to dredge sand from offshore.
Still, ten, twenty, or even fifty million dollars pales in comparison to the value of the launchpads that sit just a quarter mile inland. “To rebuild a pad is a few billion dollars,” Hall says. “To spend a few million every few years instead is a pretty good investment.”
An Atlas V rocket lifts off from Cape Canaveral Air Force Station’s Launch Complex 41, illumining nearby Kennedy Space Center’s dune restoration site. Photo Courtesy Tony Gray/NASA.
View along the beach of Kennedy Space Center’s dune restoration site in 2014. Photo Courtesy Dan Casper/NASA.
Wallops Island started hardening its defenses in earnest in the ‘90s, when NASA erected a 3.5 mile stone seawall in front of the launch pads. But while the wall initially helped to reduce storm damage, the beach beyond it was soon worn to shreds. By the mid 2000s, storm waves were breaking directly against the wall, causing sections to crumble into the sea.
And so, in the spring of 2012 and the summer of 2014, with a $54 million investment from Congress, NASA and the US Army Corps of Engineers dredged almost 4 million cubic yards of sand from offshore, and a new beach was built beyond the wall. The impact was sudden and dramatic.
“When Hurricane Irene hit in 2011, Wallops [Island] was flooded, we had $3.8 million in storm damage, and we couldn’t work there for a few weeks,” Massey says. But when Sandy, virtually the same strength as Irene, blew past Virginia’s coastline a year later? “There was no island flooding to speak of, and we could have kept the power on the entire time,” Massey says. “The only difference was our shoreline protection program.”