NASA watching waters rise right outside the front door – pt. 1

The coast is the place to be
“NASA is on the coast because that’s the right place to launch from,” said Kim Toufectis, a facilities planner in NASA’s Office of Strategic Infrastructure.

The U.S. government long ago made the choice to fly most of its rockets and experimental aircraft from the coast because failures happen, and they are less dangerous to the public when they happen over water than over land. But launching from the coast requires testing, storage, and spacecraft assembly facilities to be nearby. So if you are going into space from the United States, you are going to have to face down the challenge of rising seas.

As at Kennedy, the launch pads and buildings at Wallops Flight Facility stand just a few hundred feet from the Atlantic Ocean. Langley Research Center is situated along the Back River, near the mouth of Chesapeake Bay. Ames Research Center is tucked into the south end of San Francisco Bay.

Johnson Space Center sits on Clear Lake, an inlet off of Galveston Bay. Those centers all stand between five and forty feet (two and twelve meters) above mean sea level. The math is nearly upside down at Michoud Assembly Facility, which sits behind levees near the Mississippi River and Lake Pontchartrain.

In a review of the agency’s vulnerability to sea level rise, NASA’s Climate Adaptation Science Investigators (CASI) Working Group recently wrote:

Sea level rise of between 13 and 69 centimeters by the 2050s is projected for NASA’s five coastal centers and facilities…Even under lower sea level rise scenarios, the coastal flood event that currently occurs on average once every ten years is projected to occur approximately 50 percent more often by the 2050s in the Galveston/Johnson Space Center area; 2 to 3 times as often near Langley Research Center and Kennedy Space Center; and ten times more frequently in the San Francisco Bay/Ames Research Center area. NASA coastal centers that are already at risk of flooding are virtually certain to become more vulnerable in the future.

If you think about the height of the sea surface like the height of the water in a calm bathtub, then a rise of a few tens of centimeters over a few decades doesn’t sound like much. Sea level does not rise evenly, however; it piles up more in some places because of natural wind and current patterns. Turbulence matters: Think about that bathtub with a child sloshing around in it. Waves can roll up one side and then the other, sometimes splashing over the brim. The higher the flat-water line, the greater the chance that the water will slosh out of the basin when it is stirred up by storms and winds.

Sea level also matters in a horizontal direction. An old rule of thumb is that one inch of vertical change in sea level translates into 100 inches of horizontal beach loss on a flat beach or marsh. In this way, a little bit of sea level rise can translate into a lot of water moving inland with storms or abnormally high tides.

“Sea level is important because it gradually moves the high-tide line farther up the beach and closer to buildable land,” said John Jaeger, a coastal geologist from the University of Florida. “It also allows storm surges to penetrate farther inland.”

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 sixty-six 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 five to eight inches by the 2050s, and nine to fifteen inches by the 2080s. If ice sheets in Greenland and Antarctica continue to melt as quickly as current measurements indicate, those numbers could become twenty-one to twenty-four inches by the 2050s and forty-three to forty-nine 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.

Even as the space center was founded in 1961, management and scientists were aware that seas were rising and could someday pose a threat. But in that era, the challenge was to get to the Moon as soon as possible. There was an established Air Force station nearby with access to orbits that could not be obtained from anywhere else in the United States. The choice was easy, and it was right for the time.

Time has not been kind to this stretch of sand, however. Based on historical records and aerial photos, the beach in front of Kennedy has thinned and moved inland by as much as 200 feet (60 meters). The losses have been most acute and persistent along a stretch near the center’s two most prized launch pads. Complex 39A was recently leased for twenty years to Space X, which intends to use it for its Falcon heavy lift rocket. NASA’s new Space Launch System and Orion spacecraft are slotted for Complex 39B within the next decade. The Atlantic Ocean stands less than a quarter mile from both.

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.

For five years, Jaeger, Adams, and graduate students pulled GPS mapping gear up and down six miles of beach at least once a month — more often in the wake of storms. The goal was to build a three-dimensional model of the area. They found that the beaches were retreating due to the shape of the seafloor just offshore, where gaps between the sandbars channel wave energy toward certain areas.

They also found sand piling up (accreting) in other areas, however, mostly near Launch Complex 41. The beach is migrating south, even if NASA’s infrastructure is not.

In 2012, Hurricane Sandy offered a glimpse of the new normal along the Atlantic coast. The storm passed 200 miles offshore from Kennedy, but it moved so slowly that the heavy surf scoured the beach for three or four high-tide cycles. By the time the skies cleared, the dunes along a 2-mile (3-kilometer) stretch near Complexes 39A and B had retreated as much as 65 feet (20 meters). Nearly 650 feet (200 meters) of railroad track in the vicinity of 39A were undermined by the storm surge.

The high-tide line moved closer to a service road, under which lay some of the center’s natural gas, communications, liquefied rocket fuel, and water lines. That road sits just 4 feet (1.2 meters) above sea level.

“We were surprised that a passing storm could have that much effect. Neither Sandy nor any other recent storm made a direct hit on Kennedy, and yet there has been a lot of damage to the dunes,” said Adams. “The hurricanes get a lot of attention, but it’s the winter nor’easters that take a steady jab at these beaches.”

In the aftermath of Sandy, Kennedy Space Center shored up the beach again. Some of the railroad track was removed, and coastal engineers piled up 90,000 cubic yards of sand to create a 1.2-mile secondary dune. Roughly 180,000 plugs of native dune grasses and other vegetation were planted to hold the sand in place. So far, the dune has performed as designed, providing protection against storm and wave inundation and sea level rise for critical launch infrastructure.

In the longer run, Bray and colleagues at Kennedy are working on what they call a managed retreat. They are building up the shore defenses, while also earmarking land farther inland for additional launch infrastructure should the demand materialize.

“Kennedy Space Center may have decades before waves are lapping at the launch pads,” Jaeger said. “Still, when you put expensive, immovable infrastructure right along the coast, something’s eventually got to give.”

Tomorrow: Different NASA centers, common problems