The Camden County Board of Commissioners has been working diligently to determine a way to increase transparency about the project’s licensing information without complicating the agency’s ongoing review or releasing sensitive or export-controlled information that cannot lawfully be shared with the public. Pursuant to those goals, the County initiated the development of a publicly releasable report, prepared by The Aerospace Corporation, that describes the project’s flight safety analysis.
“We heard from Camden County residents that they wanted to better understand how Spaceport Camden could satisfy the FAA’s safety criteria. This report shows that Spaceport Camden cannot not only meet those requirements, but significantly exceeds them,” said Board of County Commission Chairman, Jimmy Starline.
Certain data used in a flight safety analysis are controlled from public release by the International Traffic in Arms Regulations (ITAR), the Missile Technology Control Regime (MTCR) and other statutes. Prior to the release of report, Camden County received guidance from the Department of Defense Office of Prepublication and Security Review to clear these issues.
The Aerospace Corporation is a nonprofit corporation that operates a Federally Funded Research and Development Center for the United States Air Force and the intelligence community and supports all national security space programs. “The Aerospace Corporation is the gold standard for flight safety analysis,” said Commission Vice-Chairman, Gary Blount. “Their work for the Department of Defense and NASA make some of their methodologies a sensitive national security issue but they are the best at what they do. I am glad we were able to clear the national security hurdles and make this information available to the public.”
There are two primary risk factors that are analyzed in a flight safety analysis: collective risk to all the population in the vicinity of a launch, also referred to as expected casualty (Ec), and individual risk (PInd) which is the risk to any one person in a government defined area (grid square). PInd is not typically required for a spaceport license application but is required for every launch license issued for an actual launch.
The collective risk is quantified in terms of the expected number of casualties for a launch mission, given certain assumptions related to the type of rocket, the trajectory flown, assumed weather and winds, anticipated / potential population in the vicinity, and many other factors, as provided by FAA regulations and generally practiced in the industry. Hundreds of thousands of launch failures are modeled as part of the flight safety analysis to calculate the various risk probabilities.
A concerted effort was made to accurately and conservatively model the design features of the representative rockets and the population in the spaceport vicinity. In addition to the local census data and specific global population density databases required to be used by federal regulation, Camden County added 380 campers, visitors and staff to Cumberland Island (CI), reflecting very conservative (and unlikely) assumptions that every campground was filled to capacity, the island contained the maximum number of visitors (300) allowed by law, and the island and its facilities were fully staffed. Further, 5350 launch spectators were added to viewing locations in and around Camden County. Finally, every habitable structure on Little Cumberland Island (LCI) and north CI near the flight trajectory was assumed to be occupied by a varying number of persons. It was further assumed that every population group in the databases used for the analysis, and citizens of Camden County, including the additional populations just described, were all outside and unsheltered, for every launch failure modeled in the analysis. Additionally, the launch vehicle was assumed to have a 5% failure probability for each stage of flight (ascent, second stage to orbit and first stage landing return, therefore 15% total failure rate). This total failure rate assumption is 50% higher than the rate required by FAA regulations.
The FAA specifies the acceptable level of cumulative risk for a launch to be less than 1 in 10,000 casualties (1x10-4) to one significant figure. This means that estimates of Ec are either rounded down or up to one significant figure when evaluated. Therefore, an estimated Ec of 1.49 per 10,000 passes the FAA requirement. The Spaceport Camden flight safety analysis of the medium-large launcher’s 100-degree reference trajectory demonstrates that it has less than 1.49 expected casualties in 10,000 over all phases of flight assuming up to 5 persons per habitable structure on LCI and north CI, and the numerous other visitors and viewers in the Camden region. If only the outbound launch operation (combined 1st stage and 2nd stage, with no first stage return to landing pad) is considered, then Ec remain less than 1.49 in 10,000 even assuming 10 persons per LCI/CI habitable structure and the additional populations. The results are shown in the table below.
As an additional consideration for operations at Spaceport Camden, an assessment of a small launch vehicle was also performed. No return flight was modeled as all current small launch vehicles are expendable, but the analysis included a higher 10% failure probability per stage of flight. Results indicate that even when assuming the largest surrounding population scenario outlined earlier, and up to 40 people per LCI/CI habitable structure the expected casualty remains less than the FAA requirement of 1.49 in 10,000.
While typically not required for a Launch Site Operator License (LSOL) application, The Aerospace Corporation calculated the Individual Risk (PInd) results for the largest rocket proposed for Spaceport Camden, a medium-large launch vehicle. The FAA requirement for PInd is less than 1 in a million to one significant figure (so less than 1.49 per million). This FAA requirement is two orders of magnitude more stringent that the cumulative risk (Ec) requirement discussed earlier. The individual risk for a representative medium-large launcher on 100-degree azimuth trajectory from Spaceport Camden was calculated to be 0.50 per million on ascent (launch) and 0.66 per million on return (landing) flight.
“Camden County spent a considerable amount of time and resources to make this Flight Safety Analysis available to the public. The report proves definitively that we can launch a wide range of launch vehicles from Spaceport Camden with more than 2000 people on Little Cumberland Island and Cumberland Island,” added Chairman Starline.
A full version of The Aerospace Corporation Flight Safety Analysis is available online at: https://issuu.com/camdencountyboc/docs/vtr-2019-01516?fr=sZjAxMDMzODE2Ng.