Year
2006
Abstract
NASA preparations for the January 19, 2006 New Horizons launch of an exploratory probe to Pluto included the development of an extensive Radiation Safety program to monitor for and respond to the potential release of alpha radiation. The exploratory probe’s power source is a radioisotope thermoelectric generator (RTG) containing roughly 11 kilograms of plutonium dioxide. While NASA estimated a 1 in 350 chance of a plutonium release, with the potential for an individual 50-year total effective dose eqivalent not to exceed 1 rem, safety regulations require that a DOE safety analysis be carried out for any mission involving an RTG. A Radiological Working Group including DOE NNSA, NASA, Lockheed Martin Valley Forge, INEL and the USAF began work in 2003 on the comprehensive safety analysis. The completed document, which outlines all equipment and teams necessary for the control of radioactive sources associated with the launch, was submitted to the Office of Science and Technology (OST) in 2005. This document called for the commissioning of a network of Environmental Continuous Air Monitors (ECAM), high volume air samplers, alpha survey meters, and FIDLER probes. In addition to 23 unmanned air sampling sites, 18 manned sites were staffed by RadMon teams from NASA, KSC, Brooks AFB, SRS, and NTS. Nine of the manned sites were equipped with Environmental Continuous Air Monitors (ECAM) allowing staff in the Radiological Control Center (RADCC) access via a wide area wireless network to real-time net plutonium concentration data from monitoring locations throughout the Kennedy Space Center and surrounding Brevard County. The LLNL National Atmospheric Release Advisory Center (NARAC) used a predetermined plutonium source term to estimate the inhalation dose commitment, ground deposition, ECAM limit of sensitivity, and recommend shelter-in-place contours on regional maps. These maps were updated at predetermined times and used to determine optimum shelter-inplace recommendations and to optimize the prepositioning of two mobile ECAMs. In the event of a launch anomaly, positive concentration data would be used by NARAC to create revised estimates of the radiation contour products. This paper will overview the launch preparations from the creation of the Radiation Safety plan, through the deployment of equipment and RadMon teams, to the actual launch day operations on the ground and in the RADCC.