What are the risk estimates of a swingby accident?
• The risk to the world population from a swingby reentry accident is very low. • A series of tests and in-depth analyses were conducted to determine and validate design strategies and measures that reduce the probability of an inadvertent Earth swingby reentry accident to less than one in one million. This small probability, which has been validated by experts outside of NASA, is achieved by biasing the spacecraft trajectory away from the Earth. The biasing strategy effects, coupled with redundant spacecraft system design, built-in fault detection and correction systems, and the ability of ground-control to send signals to the spacecraft, lead to the exceedingly small probability of Earth impact. • Even if you assume there is a swingby reentry accident, the radiation that an exposed person would be expected to receive over 50 years is thousands of times smaller than the radiation dose they will receive from natural background radiation such as radon and cosmic rays.
