EM Employee Eagerly Examines Curiosity, Continuing Decades-Long Role in Space Missions Across Solar System
An EM senior technical advisor was among the scientists and experts who helped assemble Curiosity, the rover that descended on Mars for a mission to assess environmental conditions for microbial life.
Dr. Robert C. Nelson is a scientist and chief safety officer in EM’s Office of Safety, Security and Quality Programs. He has served as an appointed ad hoc member of the Interagency Nuclear Safety Review Panel (INSRP) since 1985. That board, which reports to the Executive Office of the President, reviews risk involved with space missions powered with significant amounts of radioactive material. In the case of Curiosity, the rover included a nuclear battery containing plutonium-238 as a heat source. The mission was made possible by nuclear space power systems developed by the Energy Department.
Nelson eagerly monitored Curiosity’s descent on Mars on Aug. 6. Like the rest of the Curiosity team, he waited anxiously during the “seven minutes of terror,” the period the NASA team used to describe the rover’s landing on the Red Planet. The night before, Nelson stayed up late to watch reports from NASA’s Jet Propulsion Laboratory in Pasadena, Calif., delayed by the 14 minutes required for the radio transmissions to travel from Mars to Earth.
Curiosity’s exploration adds to a long list of missions — including Galileo, Ulysses, Cassini, Pathfinder and New Horizons — Nelson has reviewed as a member of the panel. He had served as the coordinator for the U.S Department of Defense (DOD) during approval of the Galileo mission and worked as a member of the Biomedical and Environments Effects Subpanel. Nelson recalls working on the safety evaluation report for the Galileo and Ulysses missions with a group around a conference table when they were interrupted by these instructions: “Turn on the TV; the Challenger just exploded.”
In its early years, the panel consisted of three coordinators from three federal agencies: NASA, DOE and DOD. Later, additional coordinators joined the panel, including a technical advisor from the U.S. Nuclear Regulatory Commission and a representative from the U.S. Environmental Protection Agency.
Each of the nuclear reviews by the panel is unique. Each nuclear battery, or Multi-Mission Radioisotopic Thermoelectric Generator, is designed to withstand the environment of its destination. Accordingly, each space probe comes with unique challenges. Even though Curiosity contained half the radioactive material of New Horizons, the estimated mission risks were the same because of physical arrangements necessary to land such a large rover on Mars.
Nelson continues to follow the New Horizons mission to Pluto, launched in 2006. New Horizons is not scheduled to reach the vicinity of Pluto until mid-2015.