SRAG

The Space Radiation Analysis Group (SRAG) is the NASA team at Johnson Space Center responsible for protecting astronauts from ionising radiation during spaceflight. Operating around the clock, SRAG monitors the solar and space radiation environment, models crew dose rates in real time, and has the authority to direct operational responses, including shelter-in-place orders, when radiation thresholds are approached. For Artemis II, SRAG is coordinating directly with NOAA's Space Weather Prediction Center to track solar activity during the crew's transit through cislunar space.

SRAG follows the ALARA principle (As Low as Reasonably Achievable) and uses a network of dosimeters, particle detectors, and Space weather feeds to maintain situational awareness throughout a mission. The group provides pre-flight exposure projections, inflight EVA radiation assessments, and post-flight dose reconstruction for each crewed mission. Their data feeds directly into NASA's lifetime radiation exposure limits for individual astronauts.

Beyond individual mission support, SRAG shapes hardware design, operational constraints, and crew scheduling for long-duration deep-space exploration. As Artemis missions venture beyond the Earth's magnetosphere, where astronauts are unshielded from galactic cosmic rays and solar energetic particle events, SRAG's role has grown from a monitoring function into a mission-critical operations team.